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Manual Revisions
Changes which occur after this manual is printed are described in PMRs (Publication Manual
Revisions). These PMRs provide complete replacement pages for all added, changed, and
deleted items, including pertinent parts list data, schematics, and component layout diagrams.
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The Motorola products described in this manual may include copyrighted Motorola computer
programs stored in semiconductor memories or other media. Laws in the United States and other
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Motorola products described in this manual may not be copied, reproduced, modified, reverseengineered, or distributed in any manner without the express written permission of Motorola.
Furthermore, the purchase of Motorola products shall not be deemed to grant either directly or by
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applications of Motorola, except for the normal non-exclusive license to use that arises by
operation of law in the sale of a product.
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No duplication or distribution of this document or any portion thereof shall take place without the
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Disclaimer
The information in this document is carefully examined, and is believed to be entirely reliable.
However no responsibility is assumed for inaccuracies. Furthermore, Motorola reserves the right
to make changes to any products herein to improve readability, function, or design. Motorola does
not assume any liability arising out of the applications or use of any product or circuit described
herein; nor does it cover any license under its patent rights nor the rights of others.
Trademarks
MOTOROLA, Stylized M logo, and MOTOTRBOTM are registered in the US Patent & Trademark
Office. All other products or service names are property of their respective owners.
©2006 – 2010 by Motorola, Inc.
The AMBE+2
property rights including patent rights, copyrights and trade secrets of Digital Voice Systems, Inc.
This voice coding Technology is licensed solely for use within this Communications Equipment.
The user of this Technology is explicitly prohibited from attempting to decompile, reverse
engineer, or disassemble the Object Code, or in any other way convert the Object Code into a
human-readable form.
U.S. Pat. Nos. #5,870,405, #5,826,222, #5,754,974, #5,701,390, #5,715,365, #5,649,050,
#5,630,011, #5,581,656, #5,517,511, #5,491,772, #5,247,579, #5,226,084 and #5,195,166.
TM
voice coding Technology embodied in this product is protected by intellectual
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Section 1 Introduction
1.1 Welcome to MOTOTRBOTM! ................................................................................ 1
1.2 Software Version .................................................................................................. 2
Section 2 System Feature Overview
2.1 MOTOTRBO Digital Radio Technology................................................................ 3
2.1.1 Digital Radio Technology Overview ............................................................ 3
2.1.1.1 Part One: The Analog to Digital Conversion...................................... 3
2.1.1.2 Part Two: The Vocoder and Forward Error Correction (FEC) ........... 3
2.1.1.3 Part Three: Framing........................................................................... 4
2.1.1.4 Part Four: TDMA Transmission ......................................................... 4
2.1.1.5 Standards Compliance ...................................................................... 4
2.1.2 Spectrum Efficiency via Two-Slot TDMA .................................................... 5
2.1.2.1 Frequencies, Channels, and Requirements for
Spectrum Efficiency ............................................................................... 5
2.1.2.2 Delivering Increased Capacity in Existing 12.5kHz Channels ........... 5
2.1.2.3 Two-Slot TDMA Reduces Infrastructure Equipment.......................... 6
2.1.2.4 Two-Slot TDMA Enables System Flexibility....................................... 8
2.1.2.5 Two-Slot TDMA System Planning Considerations ............................ 9
2.1.3 Digital Audio Quality and Coverage Performance....................................... 9
2.1.3.1 Digital Audio Coverage .................................................................... 10
2.1.3.2 Predicting Digital Audio Coverage ................................................... 11
2.1.3.3 User Expectations for Digital Audio Performance............................ 12
2.1.3.4 Audio Balancing............................................................................... 13
2.2 Basic System Topologies for Digital and Analog Operations ............................. 14
2.2.1 Repeater and Direct Mode Configurations................................................ 14
2.2.2 MOTOTRBO Supports Analog and Digital Operation ............................... 20
2.2.3 MOTOTRBO Channel Access .................................................................. 20
2.2.3.1 Impolite Operation (Admit Criteria of “Always”) ............................... 21
2.2.3.2 Polite to All Operation (Admit Criteria of “Channel Free”)................ 22
2.2.3.3 Polite to Own Digital System Operation (Admit Criteria of
“Color Code Free”) ............................................................................... 22
2.2.3.4 Polite to Other Analog System Operation (Admit Criteria of
“Correct PL”) ........................................................................................ 22
2.2.3.5 Polite or Impolite, or Voice Interrupt While Participating in a Call
(In Call Criteria) .................................................................................... 23
2.2.3.6 Repeater Wake-up Provisioning ...................................................... 24
2.3 MOTOTRBO Digital Features ............................................................................ 25
2.3.1 Digital Voice Features ............................................................................... 25
2.3.1.1 Group Calls...................................................................................... 25
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2.3.1.2 Private Calls..................................................................................... 26
2.3.1.3 All Call.............................................................................................. 27
2.3.2 Transmit Interrupt...................................................................................... 28
2.3.2.1 Upgrading a System to be Transmit Interrupt Capable ................... 29
2.3.3 Digital Signaling Features ......................................................................... 30
2.3.3.1 PTT ID and Aliasing......................................................................... 30
2.3.3.2 Radio Disable (Selective Radio Inhibit) ........................................... 30
2.3.3.3 Remote Monitor ............................................................................... 31
2.3.3.4 Radio Check .................................................................................... 31
2.3.3.5 Call Alert .......................................................................................... 32
2.3.3.6 Remote Voice Dekey ....................................................................... 32
2.3.4 Digital Emergency..................................................................................... 32
2.3.4.1 Emergency Alarm Only.................................................................... 35
2.3.4.2 Emergency Alarm and Call .............................................................. 35
2.3.4.3 Emergency Alarm with Voice to Follow ........................................... 36
2.3.4.4 Emergency Voice Interrupt for Emergency Alarm ........................... 37
2.3.4.5 Emergency Voice Interrupt for Emergency Voice ............................ 38
2.4 MOTOTRBO Integrated Data............................................................................. 39
2.4.1 Overview ................................................................................................... 39
2.4.2 Text Messaging Services .......................................................................... 41
2.4.2.1 Built-In Text Messaging Service ...................................................... 41
2.4.2.2 MOTOTRBO Text Messaging Application ....................................... 42
2.4.2.3 Services Provided to a Third Party Text Message Application ........ 44
2.4.3 Location Services ..................................................................................... 45
2.4.3.1 Performance Specifications ............................................................. 46
2.4.3.2 Services Provided to a Radio User.................................................. 47
2.4.3.3 Services Provided to a Location Application.................................... 47
2.4.3.4 Services Provided by the MOTOTRBO Location
Services Application............................................................................. 48
2.4.3.5 GPS Revert Channel ....................................................................... 49
2.4.3.6 Data Revert Channel ....................................................................... 50
2.4.4 Telemetry Services ................................................................................... 51
2.4.4.1 Physical Connection Information ..................................................... 52
2.4.4.2 Telemetry Examples ........................................................................ 52
2.4.5 Data Precedence and Data Over Voice Interrupt...................................... 53
2.5 Scan ................................................................................................................... 54
2.5.1 Priority Sampling ....................................................................................... 55
2.5.2 Channel Marking....................................................................................... 56
2.5.3 Scan Considerations ................................................................................. 57
2.5.3.1 Scanning and Preamble .................................................................. 58
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2.5.3.2 Channel Scan and Last Landed Channel ........................................ 59
2.5.3.3 Scan Members with Similar Receive Parameters............................ 60
2.5.4 Transmit Interrupt and Scan...................................................................... 62
2.6 Site Roaming...................................................................................................... 63
2.6.1 Passive Site Searching ............................................................................. 63
2.6.2 Active Site Searching................................................................................ 64
2.6.3 Roaming Considerations........................................................................... 66
2.6.3.1 Configuring a Roam List .................................................................. 66
2.6.3.2 Scan or Roam.................................................................................. 68
2.6.3.3 Configuring the Roaming RSSI Threshold....................................... 68
2.6.3.4 Setting Beacon Duration and Beacon Interval................................. 73
2.6.3.5 Emergency Revert, GPS Revert, and Roaming Interactions........... 75
2.6.3.6 Performance while Roaming............................................................ 76
2.7 Voice and Data Privacy ...................................................................................... 77
2.7.1 Types of Privacy........................................................................................ 77
2.7.2 Strength of the Protection Mechanism ...................................................... 78
2.7.3 Scope of Protection................................................................................... 78
2.7.4 Effects on Performance............................................................................. 79
2.7.5 User Control Over Privacy ........................................................................ 79
2.7.6 Privacy Indications to User........................................................................ 80
2.7.7 Key Mismatch............................................................................................ 81
2.7.8 Keys and Key Management ...................................................................... 81
2.7.9 Multiple Keys in a Basic Privacy System .................................................. 82
2.7.10 Data Gateway Privacy Settings............................................................... 83
2.7.11 Protecting One Group’s Message from Another ..................................... 84
2.7.12 Updating from Basic Privacy to Enhanced Privacy ................................. 84
2.8 Repeater Diagnostics and Control (RDAC)........................................................ 85
2.8.1 Connecting Remotely via the Network ...................................................... 87
2.8.2 Connecting Locally via the USB................................................................ 87
2.8.3 Connecting Locally via GPIO Lines........................................................... 87
2.8.3.1 RDAC Local Settings Rear Accessory Port CPS
Programmable Pins.............................................................................. 89
2.8.4 Redundant Repeater Setup ...................................................................... 90
2.8.5 Dual Control Considerations ..................................................................... 91
2.9 Voice Operated Transmission (VOX) ................................................................. 92
2.9.1 Operational Description............................................................................. 92
2.9.2 Usage Consideration................................................................................. 92
2.9.2.1 Suspending VOX ............................................................................. 92
2.9.2.2 Talk Permit Tone ............................................................................. 92
2.9.2.3 Emergency Calls.............................................................................. 93
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2.9.2.4 Transmit Interrupt ............................................................................ 93
2.10 Lone Worker..................................................................................................... 93
2.11 One Touch Home Revert Button ...................................................................... 94
2.12 Analog Features ............................................................................................... 94
2.12.1 Analog Voice Features............................................................................ 94
2.12.2 MDC Analog Signaling Features............................................................. 95
2.12.3 Quik-Call II Signaling Features ............................................................... 95
2.12.4 Analog Scan Features ............................................................................ 96
2.12.5 Analog Repeater Interface ...................................................................... 96
2.12.5.1 Analog Repeater Interface Settings............................................... 96
2.12.5.2 Recommended Service Aid for the MTR3000 ............................. 100
2.12.5.3 Configuration Summary Table ..................................................... 100
2.12.5.4 Configuration Considerations ...................................................... 101
2.12.6 Comparison Chart ................................................................................. 105
2.13 Application Developer Program (ADP)........................................................... 107
2.13.1 MOTOTRBO, the Dealer, and the Accredited
Third-Party Developer...................................................................................... 107
2.13.2 MOTOTRBO Applications Interfaces .................................................... 107
2.13.3 Documents of MOTOTRBO ADP.......................................................... 109
2.13.4 Available Levels of Partnership............................................................. 110
Section 3 System Components and Topologies
3.1 System Components ........................................................................................ 113
3.1.1 Fixed End Components........................................................................... 113
3.1.1.1 Repeater ........................................................................................ 113
3.1.1.2 Radio Control Station..................................................................... 115
3.1.1.3 MC1000, MC2000, MC2500 Console............................................ 116
3.1.2 Mobile Components ................................................................................ 116
3.1.2.1 MOTOTRBO Portable.................................................................... 117
3.1.2.2 MOTOTRBO Mobile ...................................................................... 122
3.1.3 Data Applications .................................................................................... 127
3.1.3.1 Application Server.......................................................................... 127
3.1.3.2 Presence Notifier ........................................................................... 127
3.1.3.3 Multi-Channel Device Driver (MCDD)............................................ 128
3.1.3.4 Text Messaging Application........................................................... 128
3.1.3.5 MotoLocator Location Tracking Server
(Not Supported in Capacity Plus)....................................................... 130
3.2 System Topologies........................................................................................... 132
3.2.1 Direct Mode............................................................................................. 132
3.2.1.1 Digital MOTOTRBO Radios in Direct Mode................................... 133
3.2.1.2 Interoperability between Analog MOTOTRBO Radios and Analog
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Radios in Direct Mode........................................................................ 142
3.2.1.3 Interoperability between Digital MOTOTRBO Radios, Mixed Mode
MOTOTRBO Radios, and Analog Radios in Direct Mode.................. 143
3.2.2 Repeater Mode ....................................................................................... 143
3.2.2.1 Digital MOTOTRBO Radios in Repeater Mode ............................. 145
3.2.2.2 Analog MOTOTRBO Radios in Repeater Mode ............................ 156
3.2.3 IP Site Connect Mode ............................................................................. 157
3.2.3.1 Topologies of IP Site Connect System .......................................... 158
3.2.4 Capacity Plus Mode ................................................................................ 168
3.2.4.1 Topologies of Capacity Plus System ............................................. 168
Section 4 System Design Considerations
4.1 Purpose ........................................................................................................... 175
4.2 Migration Plans................................................................................................. 175
4.2.1 Pre-Deployment System Integration ....................................................... 175
4.2.2 Analog to Digital Preparation and Migration............................................ 176
4.2.3 New/Full System Replacement ............................................................... 177
4.3 Frequency Licensing ........................................................................................ 178
4.3.1 Acquiring New Frequencies (Region Specific)........................................ 178
4.3.2 Converting Existing 12.5/25kHz Licenses............................................... 179
4.3.3 Repeater Continuous Wave Identification (CWID).................................. 179
4.4 Digital Repeater Loading.................................................................................. 180
4.4.1 Assumptions and Precautions................................................................. 180
4.4.2 Voice and Data Traffic Profile ................................................................. 181
4.4.3 Estimating Loading (Single Repeater and IP Site Connect) ................... 182
4.4.4 Estimating Loading (For Capacity Plus).................................................. 183
4.4.5 Loading Optimization (For Single Repeater and IP Site Connect).......... 186
4.4.5.1 Distribution of High Usage Users................................................... 186
4.4.5.2 Minimize Location Periodic Update Rate....................................... 187
4.4.5.3 Data Application Retry Attempts and Intervals .............................. 189
4.4.5.4 Optimize Data Application Outbound Message Rate .................... 189
4.4.5.5 GPS Revert and Loading............................................................... 190
4.4.6 Loading Optimization (For Capacity Plus)............................................... 194
4.4.6.1 Preference for Using a Frequency................................................. 194
4.4.6.2 Improving Channel Capacity by Adjusting Hang Times................. 194
4.4.6.3 Call Priority in Capacity Plus Mode................................................ 195
4.4.6.4 Call Initiation in Capacity Plus Mode ............................................. 195
4.5 Multiple Digital Repeaters in Standalone Mode ............................................... 196
4.5.1 Overlapping Coverage Area.................................................................... 196
4.5.2 Color Codes in a Digital System ............................................................. 197
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4.5.3 Additional Considerations for Color Codes ............................................. 198
4.6 Multiple Digital Repeaters in IP Site Connect Mode......................................... 199
4.6.1 System Capacity ..................................................................................... 199
4.6.2 Frequencies and Color Code Considerations ......................................... 199
4.6.3 Considerations for the Backend Network................................................ 200
4.6.3.1 Automatic Reconfiguration............................................................. 201
4.6.3.2 Characteristics of Backend Network.............................................. 202
4.6.4 Flow of Voice/Data/Control Messages.................................................... 209
4.6.5 Security Considerations .......................................................................... 210
4.6.6 General Considerations When Setting Up the Network Connection
for an IP Site Connect System......................................................................... 211
4.6.7 General Considerations When Utilizing the RDAC Application to
Set Up the Network Connection ...................................................................... 212
4.6.8 Considerations for Shared Use of a Channel.......................................... 213
4.6.9 Migration from Single Site Systems ........................................................ 214
4.6.10 Migration from an Older IP Site Connect System ................................. 215
4.7 Multiple Digital Repeaters in Capacity Plus...................................................... 216
4.7.1 System Capacity ..................................................................................... 216
4.7.2 Frequencies and Color Code Considerations ......................................... 216
4.7.3 Considerations for the Backend Network................................................ 217
4.7.4 Behaviors in Presence of Failures .......................................................... 217
4.7.5 Limiting Interference to Other Systems................................................... 218
4.7.6 Plan for Talkaround Mode....................................................................... 218
4.7.7 Ways to Improve Battery Life .................................................................. 219
4.7.8 MOTOTRBO Telemetry Connection Details ........................................... 219
4.7.9 Considerations for Configuring Mixed Firmware Versions...................... 219
4.8 Transmit Interrupt System Design Considerations........................................... 220
4.8.1 Interruptible Radios ................................................................................. 220
4.8.2 Voice Interrupt......................................................................................... 220
4.8.3 Emergency Voice Interrupt...................................................................... 221
4.8.4 Data Over Voice Interrupt ....................................................................... 222
4.8.5 Remote Voice Dekey .............................................................................. 222
4.9 Data Sub-System Design Considerations ........................................................ 223
4.9.1 Computer and IP Network Configurations............................................... 223
4.9.1.1 Radio to Mobile Client Network Connectivity................................. 223
4.9.1.2 Radio to Air Interface Network Connectivity .................................. 224
4.9.1.3 Application Server Control Station Network Connectivity .............. 227
4.9.1.4 Control Station Considerations ...................................................... 228
4.9.1.5 Multi-Channel Device Driver (MCDD) and Required
Static Routes...................................................................................... 230
4.9.1.6 Application Server and Dispatcher Network Connectivity.............. 230
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4.9.1.7 MOTOTRBO Subject Line Usage.................................................. 231
4.9.1.8 MOTOTRBO Example System IP Plan ......................................... 231
4.9.1.9 Application Server Network Connection Considerations ............... 233
4.9.1.10 Reduction in Data Messages (When Radios Power On)............. 233
4.9.1.11 Ways to Improve Data Throughput.............................................. 234
4.9.1.12 Data Revert Channels for Capacity Plus ..................................... 235
4.9.2 Data Application Licensing Considerations............................................. 238
4.9.3 Mobile Terminal and Application Server
Power Management Considerations................................................................ 239
4.9.4 MOTOTRBO Telemetry Connection Details ........................................... 239
4.10 Customer Fleetmap Development.................................................................. 240
4.10.1 Identifying a Functional Fleetmap Design Team................................... 240
4.10.2 Identifying Radio Users......................................................................... 241
4.10.3 Organizing Radio Users into Groups .................................................... 242
4.10.3.1 Configuration of Groups............................................................... 243
4.10.4 Assigning IDs and Aliases..................................................................... 243
4.10.4.1 Identifying Radio IDs.................................................................... 244
4.10.4.2 Assigning Radio Aliases .............................................................. 244
4.10.4.3 Identifying Group IDs ................................................................... 245
4.10.4.4 Assigning Group Aliases.............................................................. 245
4.10.5 Determining Which Channel Operates in Repeater Mode
or Direct Mode ................................................................................................. 246
4.10.6 Determining Feature Assignments........................................................ 246
4.10.6.1 Determining Supervisor Radios ................................................... 246
4.10.6.2 Private Calls................................................................................. 246
4.10.6.3 All Call.......................................................................................... 247
4.10.6.4 Radio Disable .............................................................................. 247
4.10.6.5 Remote Monitor ........................................................................... 247
4.10.6.6 Radio Check ................................................................................ 248
4.10.6.7 Call Alert ...................................................................................... 248
4.10.6.8 RX Only ....................................................................................... 248
4.10.6.9 Remote Voice Dekey ................................................................... 248
4.10.7 Emergency Handling Configuration ...................................................... 249
4.10.7.1 Emergency Handling User Roles................................................. 249
4.10.7.2 Emergency Handling Strategies .................................................. 250
4.10.7.3 Acknowledging Supervisors in Emergency.................................. 252
4.10.7.4 Extended Emergency Call Hang Time......................................... 252
4.10.7.5 Emergency Revert and GPS Revert Considerations................... 252
4.10.8 Channel Access Configuration.............................................................. 257
4.10.9 Zones and Channel Knob Programming............................................... 258
4.11 Base Station Identifications (BSI) Setting
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Considerations ....................................................................................................... 259
4.12 GPS Revert Considerations (For Single Repeater and
IP Site Connect only).............................................................................................. 261
4.13 Failure Preparedness ..................................................................................... 262
4.13.1 Direct Mode Fallback (Talkaround) ....................................................... 262
4.13.2 Uninterrupted Power Supplies (Battery Backup)................................... 262
4.14 Dynamic Mixed Mode System Design Considerations................................... 263
4.14.1 Dynamic Mixed Mode System Configuration Considerations ............... 263
4.14.2 Loading Considerations in a Dynamic Mixed Mode System ................. 265
4.15 Configurable Timers ....................................................................................... 266
Section 5 Sales and Service Support Tools
5.1 Purpose ............................................................................................................ 271
5.2 Applications Overview ...................................................................................... 271
5.3 Service Equipment ........................................................................................... 271
5.3.1 Recommended Test Equipment.............................................................. 271
5.4 Documentation and Trainings .......................................................................... 273
5.4.1 MOTOTRBO Documentation .................................................................. 273
Section A Replacement Parts Ordering
A.1 Basic Ordering Information .............................................................................. 275
A.2 Motorola Online................................................................................................ 275
A.3 Mail Orders ...................................................................................................... 275
A.4 Telephone Orders ............................................................................................ 275
A.5 Fax Orders ....................................................................................................... 275
A.6 Parts Identification ........................................................................................... 275
A.7 Product Customer Service ............................................................................... 276
Section B Control Station Installation
B.1 Data Bearer Service......................................................................................... 277
B.2 Interference...................................................................................................... 278
B.3 Control Station Installation Considerations ...................................................... 279
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Introduction 1
SECTION 1 INTRODUCTION
1.1 Welcome to MOTOTRBOTM!
Improving workforce productivity and operational effectiveness requires superior communications
quality, reliability, and functionality. MOTOTRBO is the first digital two-way radio system from
Motorola specifically designed to meet the requirements of professional organizations that need a
customizable, business critical, private communication solution using licensed spectrum.
MOTOTRBO combines the best in two-way radio functionality with digital technology to deliver
increased capacity and spectral efficiency, integrated data applications and enhanced voice
communications.
MOTOTRBO is an integrated voice and data system solution comprising of mobile and portable
radios, audio and energy accessories, repeaters, text messaging and location tracking
applications, and a third party application developers program.
Figure 1.1 MOTOTRBO System
This system planner will enable the reader to understand the features and capabilities of the
MOTOTRBO system, and will provide guidance on how to deploy and configure the system and its
components to take advantage of its advanced capabilities.
This system planner is divided into 5 sections, with the first being this introduction. Section 2
provides an overview of system level features. Section 3 describes the system components in
more detail. Section 4 provides guidance on system design considerations including configuration
of components. Section 5 provides product sales and support information.
This system planner is complementary to additional training and documentation including:
• Radio Customer Programming Software (CPS) and related training
• System workshop/system service training
• Product specification sheets
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2 Introduction
1.2 Software Version
All the features described in the System Planner are supported by the radio’s software version
R01.06.10 or later.
The initial MTR3000 firmware version 1.00.03 released in 2010 does not support MOTOTRBO
features introduced in XPR 8300 firmware version 1.06.00 onwards.
Example: The Transmit Interrupt feature is not supported in the MTR3000 firmware version
1.00.03.
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System Feature Overview 3
SECTION 2 SYSTEM FEATURE OVERVIEW
2.1 MOTOTRBO Digital Radio Technology
This section provides a brief overview of MOTOTRBO digital radio technology. It addresses two of
the primary benefits delivered by this technology: spectral efficiency and improved audio
performance.
2.1.1 Digital Radio Technology Overview
The digital radio technologies employed by MOTOTRBO can be summarized as follows:
or
1 2 3 4
Figure 2-1 MOTOTRBO Digital Radio Technology
Figure 2-1 “MOTOTRBO Digital Radio Technology” is broken down into four parts which are
described in the following subsections.
2.1.1.1 Part One: The Analog to Digital Conversion
When a radio user presses the Push-To-Talk (PTT) button and begins speaking, his voice is
received by the radio microphone and converted from an acoustic waveform to an analog
electrical waveform. This voice waveform is then sampled by an analog to digital converter. In
typical radio applications, a 16-bit sample is taken every 8kHz, this produces a 128,000bps (bits
per second) digital bitstream, which contains far too much information to send over a 12.5kHz or
25kHz radio channel. Therefore some form of compression is required.
2.1.1.2 Part Two: The Vocoder and Forward Error Correction (FEC)
Vocoding (Voice encoding) compresses speech by breaking it into its most important parts and
encoding them with a small number of bits, while greatly reducing background noise. Vocoding
compresses the voice bitstream to fit the narrow (for MOTOTRBO) 6.25kHz equivalent radio
channel. The MOTOTRBO vocoder is AMBE+2
Inc. (DVSI), a leader in the vocoding industry. This particular vocoder works by dividing speech
into short segments, typically 20 to 30 milliseconds in length. Each segment of speech is analyzed,
and the important parameters such as pitch, level, and frequency response are extracted. These
parameters are then encoded using a small number of digital bits. The AMBE+2
TM
which was developed by Digital Voice System,
TM
vocoder is the
6880309T12 March 2010
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4 System Feature Overview
first to demonstrate very low bit rates while producing toll-quality speech such as traditionally
associated with wireline telephone systems.
Together with the vocoding process, Forward Error Correction (FEC) is also applied. FEC is a
mathematical checksum technique that enables the receiver to both validate the integrity of a
received message and determine which, if any, bits have been corrupted. FEC enables the
receiver to correct bit errors that may have occurred due to radio frequency (RF) channel
impairment. This effectively rejects noise that can distort an analog signal and by comparison
enables more consistent audio performance throughout the coverage area. At this stage, the
vocoder has already compressed the 128,000bps input signal to 3,600bps.
2.1.1.3 Part Three: Framing
In framing, the vocoded speech is formatted for transmission. This includes organizing the voice
and any embedded signaling information (such as color code, group ID, PTT ID, call type, etc.)
into packets. These packets form a header and payload type of structure – the header contains the
call control and ID information, and the payload contains the vocoded speech. This same structure
can also relay Internet Protocol (IP) data packets – the IP packets are simply an alternative form of
payload to the MOTOTRBO radio. The header information is repeated periodically throughout the
transmission, thereby improving the reliability of the signaling information as well as enabling a
receiving radio to join a call that may already be in progress – we refer to this condition as “late
entry”.
2.1.1.4 Part Four: TDMA Transmission
Finally, the signal is encoded for a Frequency Modulation (FM) transmission. The bits contained in
the digital packets are encoded as symbols representing the amplitude and phase of the
modulated carrier frequency, amplified, and then transmitted.
TDMA (Time Division Multiple Access) organizes a channel into 2 time slots: a given radio’s
transmitter is active only for short bursts, which provides longer battery life. By transmitting only on
their alternating time slots, two calls can share the same channel at the same time without
interfering with one another, thereby doubling spectrum efficiency. Using TDMA, a radio transmits
only during its time slot (i.e. it transmits a burst of information, then waits, then transmits the next
burst of information).
2.1.1.5 Standards Compliance
The digital protocols employed in MOTOTRBO (from vocoding and forward error correction to
framing, transmission encoding, and transmission via two-slot TDMA) are fully specified by the
1
ETSI
DMR2 Tier 23 Standard, which is an internationally recognized standard with agreements
among its supporting members. Although formal interoperability testing and verification processes
for this standard have yet to fully mature, Motorola anticipates that MOTOTRBO radio systems will
be interoperable with other solutions that comply to the ETSI DMR Tier 2 standard.
1. European Telecommunications Standards Institute
2. Digital Mobile Radio
3. Tier 2 indicates full power conventional operation in licensed channels for professional and commercial
users.
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System Feature Overview 5
2.1.2 Spectrum Efficiency via Two-Slot TDMA
2.1.2.1 Frequencies, Channels, and Requirements for Spectrum Efficiency
A radio communications channel is defined by its carrier frequency, and its bandwidth. The
spectrum of available carrier frequencies is divided into major bands (such as 800/900 MHz, VHF,
and UHF), and the majority of licensed channels in use today have widths of either 25kHz or
12.5kHz. As the airwaves have become increasingly crowded, new standards and technologies
that allow more radio users to share the available spectrum in any given area are needed. The
demand for greater spectral efficiency is being driven, in part, by regulatory agencies. In the U.S.,
for example, the Federal Communications Commission (FCC) requires manufacturers to offer only
devices that operate within 12.5kHz VHF and UHF channels by 2011. By the year 2013, all VHF
and UHF users are required to operate in 12.5kHz channels.
The next logical step is to further improve the effective capacity of 12.5kHz channels. While there
is no current mandate requiring a move to 6.25kHz, such discussions are on-going at the FCC and
other agencies. It’s only a matter of time before the ability to carry two voice paths in a single
12.5kHz channel, also known as 6.25kHz equivalent efficiency, becomes a requirement in 800/900
MHz, VHF, and UHF bands. Presently, FCC rules are in place to mandate manufacturers to build
radios capable of the 6.25kHz efficiency for 800/900 MHz, VHF, and UHF bands, but the
enforcement of these rules are put on hold. In the meantime, MOTOTRBO offers a way to divide a
12.5kHz channel into two independent time slots, thus achieving 6.25kHz-equivalent efficiency
today.
2.1.2.2 Delivering Increased Capacity in Existing 12.5kHz Channels
MOTOTRBO uses a two-slot TDMA architecture. This architecture divides the channel into two
alternating time slots, thereby creating two logical channels on one physical 12.5kHz channel.
Each voice call utilizes only one of these logical channels, and each user accesses a time slot as if
it is an independent channel. A transmitting radio transmits information only during its selected
slot, and will be idle during the alternate slot. The receiving radio observes the transmissions in
either time slot, and relies on the signaling information included in each time slot to determine
which call it was meant to receive.
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6 System Feature Overview
A
Today’s Analog
MOTOTRBO
By comparison, analog radios operate on the concept of Frequency Division Multiple Access
(FDMA). In FDMA, each transmitting radio transmits continuously on a designated channel, and
the receiving radio receives the relevant transmission by tuning to the desired carrier frequency.
Today’s Analog
Regulatory
emissions
mask
Frequency
12.5KHz channel
12.5kHz Analog
- 1 voice for each 12.5kHz channel
- A single repeater for each channel
TDMA thereby offers a straightforward method for achieving 6.25kHz equivalency in 12.5kHz
repeater channels – a major benefit for users of increasingly crowded licensed bands. Instead of
dividing channels into smaller slices of decreased bandwidth – which is what would be required to
increase spectrum efficiency with FDMA methods, TDMA uses the full 12.5kHz channel
bandwidth, but increases efficiency by dividing it into two alternating time slots. Additionally, this
method preserves the well-known radio frequency (RF) performance characteristics of the
12.5kHz signal. From the perspective of RF physics – that is, actual transmitted power and
radiated emissions – the 12.5kHz signal of two-slot TDMA occupies the channel, propagates, and
performs essentially in the same way as today’s 12.5kHz analog signals. With the added
advantages of digital technology, TDMA-based radios can work within a single repeater channel to
provide roughly twice the traffic capacity, while offering RF coverage performance equivalent to, or
better than, today’s analog radio.
MOTOTRBO
Time
Slot 1
Frequency
12.5KHz channel
12.5kHz TDMA
- Divides existing channel into two timeslots
- Delivers twice the capacity through repeater
- Performance is same or better than 12.5kHz FDM
- Single repeater does work of two repeaters
- Reduces need for combining equipment
- Enables 40% increase in radio battery life
Figure 2-2 Comparison between Today’s Analog and MOTOTRBO
Slot 2
Slot 1
Slot 2
Slot 1
Slot 2
2.1.2.3 Two-Slot TDMA Reduces Infrastructure Equipment
As we have seen, two-slot TDMA essentially doubles repeater capacity. This means that one
MOTOTRBO repeater does the work of two analog repeaters (a MOTOTRBO repeater supports
two calls simultaneously). This saves costs of repeater hardware and maintenance, and also
saves on the cost and complexity of RF combining equipment necessary in multi-channel
configurations. Just as importantly, the two-slot TDMA signal fits cleanly into a customer’s existing,
licensed channels; there is no need to obtain new licenses for the increase in repeater capacity,
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System Feature Overview 7
and compared to alternative technologies that may operate on different bandwidths, there is no
comparative increase in the risk of interference with or from adjacent channels.
Analog 2-Channel System
12.5kHz Analog
Frequency Pair 1
Repeater 1
Tx1
Repeater 2
Repeater 3
Rx1
Tx2
Rx2
Tx3
Rx3
Combining
Equipment
MOTOTRBO 2-Channel System
12.5kHz TDMA
Tx
Rx
Duplexer
Frequency Pair 2
Frequency Pair
Groups
Repeater
Groups
Figure 2-3 MOTOTRBO Requires Less Combining Equipment
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8 System Feature Overview
2.1.2.4 Two-Slot TDMA Enables System Flexibility
The two time slots or logical channels enabled by two-slot TDMA can potentially be used for a
variety of purposes. Many organizations deploying MOTOTRBO systems can use these slots in
the following manner:
• Use both the slots as voice channels. This doubles the voice capacity per licensed
repeater channel, thereby
• increasing the number of users the system can accommodate, and
• increasing the amount of air time the users can consume.
• Use both slots as data channels. This allows the organizations to fully deploy data
transactions
• Use one slot as a voice channel, and the other as a data channel. This is a flexible
solution, that allows customers to equip their voice users with mobile data, messaging,
or location tracking capabilities.
In any of these scenarios, additional benefits are realized within the existing licensed repeater
channel(s).
Voice Call 1 (or Data)
Timeslot 1 Timeslot 1 Timeslot 1Timeslot 2 Timeslot 2 Timeslot 2
Voice Call 2 (or Data)
Figure 2-4 Example of Two-Slot TDMA
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System Feature Overview 9
NOTE: When used in direct mode without a repeater, two-slot TDMA systems on a 12.5kHz
channel do not deliver 6.25kHz equivalent efficiency. This is because the repeater is
necessary to synchronize the time slots to enable independent parties to share them.
Thus, on a direct or talkaround channel, when one radio begins transmitting, the whole
12.5kHz channel is effectively busy, even though the transmitting radio is using only one
time slot. The alternate time slot is unavailable for another, independent voice call.
However, the alternate time slot can potentially be utilized as a signaling path. The ETSI
DMR Tier 2 standard refers to this capability as Reverse Channel signaling, and it is
envisioned to be used to deliver important future benefits to professional users, such as
priority call control, remote-control of the transmitting radio, and emergency call preemption. This future capacity for reverse channel signaling is a unique capability of TDMA
technology and, if supported by your system, may be deployed in both repeater and direct/
talkaround configurations. At this time, the MOTOTRBO system does NOT support
Reverse Channel signaling.
2.1.2.5 Two-Slot TDMA System Planning Considerations
System Planning considerations associated with the increased capacity and the flexibility of the
MOTOTRBO two-slot TDMA architecture include:
• Capacity planning:
• How many voice and data users do you have?
• What usage profiles are anticipated?
• How many channels and repeaters are needed?
These questions are addressed in more detail in “System Design Considerations” on page 175.
• Fleetmapping:
• How to map users, voice services and data services such as messaging or location
tracking to channels.
Voice and data service capabilities are described in more detail in this module and in “System
Components and Topologies” on page 113. Fleetmapping considerations are addressed in more
detail in “System Design Considerations” on page 175, in the MOTOTRBO Systems Training, and
within the MOTOTRBO radio CPS.
• Migration Planning:
• How to migrate existing channels to digital channels?
• What updates to licensing requirements may be needed?
These questions are addressed in mode detail in Section 4 “System Design Considerations” on
page 175.
2.1.3 Digital Audio Quality and Coverage Performance
This section describes how digital audio drives coverage performance. It also sets expectations for
how digital audio behaves and sounds from the end-user’s perspective.
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10 System Feature Overview
2.1.3.1 Digital Audio Coverage
The main difference between analog and digital coverage is how the audio quality degrades
throughout the coverage region. Analog audio degrades linearly throughout the region of
coverage, while digital audio quality performs more consistently in the same region of coverage. A
primary reason for the different degradation characteristics is the use of forward error correction
coding used in digital transmissions, which can accurately deliver both audio and data content with
virtually no loss over a far greater area.
It is this error protection that allows a MOTOTRBO system to provide consistent audio quality
throughout its coverage area. A comparable analog system can never offer such consistency. In
the MOTOTRBO system, the audio quality remains at a high level, because the error protection
minimizes the noise effect.
The figure below graphically illustrates the relationship of delivered system audio quality, while
comparing good to poor audio quality with strong to weak signal strength. Do note that
• In very strong signal areas the analog signal, because there is no processing, may
sound slightly better than the digital audio signal.
• Digital signals increase the effective coverage area above the minimally acceptable
audio quality level.
• Digital signals improve the quality and consistency of the audio throughout the effective
coverage area.
• Digital signals do not necessarily increase the total distance that an RF signal
propagates.
Figure 2-5 Comparison of Audio Quality versus Signal Strength for Analog and Digital
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System Feature Overview 11
2.1.3.2 Predicting Digital Audio Coverage
Predicting coverage for a radio site can be complicated. There are many factors that affect RF
performance prediction, and generally, the more factors that can be considered, the more accurate
the prediction of coverage. Perhaps the most influential factor is the selection of the RF
propagation model and/or RF prediction software tools.
Coverage prediction techniques for analog and digital systems generally follow the same basic
procedures, and require similar sets of input factors. Therefore, if the site’s analog coverage
footprint is already known, it is easier to plan the site’s digital coverage footprint. This approach
allows the system designer to use their existing analog site coverage prediction techniques,
whether simple or complex, and then translate the results of the analog coverage prediction to
predict digital coverage.
Delivered Audio Quality (DAQ) is a method to quantify audio quality. It is a measure of the
intelligibility and quality of voice transported through a communications system, as defined in TIA
TSB-88. DAQ reports audio quality on a 5 point scale, with a DAQ rating of 3 considered as the
minimal acceptable level of audio quality for public safety applications. The definition of DAQ 3 is
“Speech understandable with slight effort and occasional repetition required due to Noise/
Distortion.”.
When comparing an analog site and a MOTOTRBO site, the relative regions of coverage offering
comparable audio quality are illustrated in the figure below.
Analog Digital
Improving Audio Quality
Figure 2-6 Differences in Analog Coverage
For a DAQ 3 audio quality, MOTOTRBO provides a greater usable range than analog, when all
other factors are considered equal (e.g. transmit power level, antenna height, receiver noise
figures, IF filter bandwidths, no audio processing – such as Hear Clear – on the analog radios,
terrain, antenna combining equipment, etc.).
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12 System Feature Overview
For an advanced, more comprehensive understanding of RF coverage prediction for the
MOTOTRBO site, the reader is encouraged to obtain the TIA Telecommunications Service Bulletin
TSB-88 – “Wireless Communications Systems-Performance in Noise and Interference-Limited
Situations, Recommended Methods for Technology-Independent Modeling, Simulation, and
Verification.”
A copy of TSB-88 can be obtained from http://www.tiaonline.org
2.1.3.3 User Expectations for Digital Audio Performance
There are a number of differences between how digital audio behaves compared to analog audio
from the end user (listener’s) perspective. Motorola has found that setting proper end user
expectations in this regard is an important aspect of system planning.
What End-Users will Experience with Digital Audio
• Consistent performance throughout coverage area with no gradual fade at the
fringes: While analog signals slowly degrade as the receiver moves away from the
transmitter, digital signals perform more consistently throughout the coverage area.
However, digital signals, more abruptly, shift from “good” to “no signal”, when crossing
the fringe of the coverage area. This means, users cannot rely on degrading audio
quality to warn them that they are approaching the fringe of coverage. On the other
hand, just prior to the fringe of the coverage area, digital audio is still crisp and clean,
whereas analog audio has excessive noise and static.
• Digital Sounds Different: The vocoding process is designed to deliver optimum audio
quality with a very small number of bits. Some listeners find the resulting tonal qualities
of digital speech somewhat different from what they have experienced with analog
speech. Because the vocoding process is highly specialized for reproducing human
speech, other sounds like music and tones are not reproduced accurately. Additionally,
digital audio can introduce end-to-end audio delays. When overwhelming errors or
dropouts are encountered, digital radios can generate some unique-sounding audio
“artifacts”.
• Background Noise Reduction: The advanced vocoding capabilities in MOTOTRBO
also include background noise reduction. Regardless of what is happening in the
environment of the transmitting radio, only voice is reconstructed at the receiving radio –
background noise, like machine noise, wind noise, and traffic noise, is not
reconstructed, and thus, not heard. This is a key advantage of the MOTOTRBO digital
voice solution over typical analog solutions, because noisy environments like factories,
stores, work sites, and windy locations do NOT significantly degrade communication
intelligibility.
What End-Users will NOT Experience with Digital Audio:
• Digital radio is not “CD Quality.” MOTOTRBO is the first radio in the industry to use
the AMBE+2
users should not be misled into thinking that “communications grade” digital audio
quality in radio systems is analogous to the high fidelity audio quality of CD’s and DVD’s.
• Digital cannot solve historic problems. System issues with coverage and
interference are not necessarily eliminated by switching to digital. Adjacent or cochannel interference may sound different to a digital user, but digital technology does
not solve interference issues. For example, analog interference will not be heard as
voice to a digital radio and vice versa, but disruption of system performance can still
occur.
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TM
low bit rate vocoder to deliver communications grade voice quality. End
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System Feature Overview 13
2.1.3.4 Audio Balancing
Transmitting voice over a digital air interface requires a voice coder, or vocoder for short. The
TM
vocoder used by MOTOTRBO is the Digital Voice Systems Inc. (DVSI) AMBE+2
delivers excellent voice quality with robustness to both background noise and RF channel bit
errors in a 6.25kHz equivalent channel bandwidth. In order to produce optimal voice quality, the
input level into the vocoder must fall within a specific amplitude range.
The diverse nature of users with respect to mouth-to-microphone distance as well as voice level
and directivity can make this a bit problematic. In an effort to produce optimal voice quality over
these diverse input conditions, MOTOTRBO digital always employs Automatic Gain Control (AGC)
in the audio transmit path. The primary function of the transmit AGC is to produce the best voice
quality possible under real life conditions. Since voice is still the main application of a two-way
radio, this is a primary goal.
A secondary result of the AGC is to produce flat received speech loudness level over a range of
input levels at the microphone. The usage of IMPRES Accessories extends this input range so
optimal voice quality occurs over an even greater input range. Figure 2-7 “Transmit Audio
Sensitivity”illustrates this extended range flat response in the curve titled MOTOTRBO with
IMPRES RSM (Digital). This same response curve can also be produced in analog mode by using
a IMPRES Accessory and enabling Analog Mic AGC in the CPS General Settings. Figure 2-7
illustrates this type of response in the curve titled MOTOTRBO with IMPRES RSM (AGC on,
Analog). An advantage of this type of response is that soft talkers and users that turn away from
the microphone while speaking will still come through loud and clear.
. This vocoder
100
95
90
85
80
Receiver Output Speech Loudness
75
80 85 90 95 100 105 110
Transmitter Input [dB SPL]
Pr of ess ional Series
MOTOTRBO with IMPRES RSM (AGC off, A nalog)
MOTOTRBO with IMPRES RSM (AGC on, Analog)
MOTOTRBO with IMPRES RSM (Digital)
Figure 2-7 Transmit Audio Sensitivity
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14 System Feature Overview
The flat audio response of digital is different from the traditional analog audio response. The
traditional response is a linear response and the louder one speaks, then the louder the received
volume. Figure 2-7 illustrates a traditional analog response in the curves titled Professional Series
and MOTOTRBO with IMPRES RSM (AGC off, Analog). When Analog Mic AGC is disabled, then
the Analog Mic Gain (dB) is adjustable in the CPS General Settings. Therefore, MOTOTRBO in
analog mode is able to deliver the traditional analog response and is adjustable to fit into existing
systems.
Examination of Figure 2-7 indicates that digital and traditional analog responses are similar at an
input Sound Pressure Level (SPL) of 98 dB. Below this level, analog is quieter than digital. This is
important to note as a system requiring MOTOTRBO to function as a digital radio and also as an
analog radio during migration, may experience received audio level differences that are mode
dependant. This could occur when scanning both digital and analog channels and the analog
talker is located in a quiet environment such as an office. In quiet environments many users tend
to speak softly and therefore the input will fall below the equivalent response level of 98 dB SPL.
Therefore, during the migration period, the analog response may be quieter than the digital
response.
2.2 Basic System Topologies for Digital and Analog Operations
MOTOTRBO is a conventional radio system. In its most basic form, a MOTOTRBO system is
comprised of radios that communicate to each other directly in direct mode, through a repeater in
repeater mode, or through a set of repeaters in IP Site Connect Mode. The MOTOTRBO system
can be configured to operate in analog mode, digital mode, or in both modes.
2.2.1 Repeater and Direct Mode Configurations
In direct mode, receive and transmit functions are both carried out on the same physical channel
(i.e. transmit and receive frequencies are the same).
1. When operating in Analog Direct Mode, MOTOTRBO supports one voice path (transmit
and receive) on one physical channel, and can be configured to operate in 25kHz channel
bandwidth systems and/or 12.5kHz channel bandwidth systems.
2. When operating in Digital Direct Mode, MOTOTRBO uses one physical channel
configured for a 12.5kHz channel bandwidth. On that one direct 12.5kHz physical channel
bandwidth, a MOTOTRBO digital system can support only one voice (or data) path at a
time. Without a repeater in place to coordinate the time slot sequence among radios, only
one radio can transmit at a time in order to guarantee transmissions do not overlap.
In repeater-based radio communications systems, a voice path requires a pair of channels: one for
transmission, the other for reception.
1. When operating in Analog Repeater Mode, MOTOTRBO operates similar to existing
analog repeaters by supporting one voice path (transmit and receive) on one pair of
physical channels, and can be configured to operate in 25kHz channel bandwidth systems
and/or 12.5kHz channel bandwidth systems.
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System Feature Overview 15
2. When operating in Digital Repeater Mode, MOTOTRBO uses a pair of physical channels
configured for 12.5kHz channel bandwidth. Through the use of Time Division Multiple
Access (TDMA) technology and the synchronization provided by the repeater,
MOTOTRBO splits each 12.5kHz channel (one transmit and one receive) into two
independent time slots or logical channels within the 12.5kHz physical channel bandwidth.
This allows the user to assign voice or data traffic to either of the time slots independently.
To the end user, this means they now have two voice or data channels that can be
managed independently, instead of one. These two logical channels (two time slots) can
transmit and receive independently of each other.
3. When operating in Dynamic Mixed Mode, MOTOTRBO uses a pair of physical channels
configured for 12.5kHz channel bandwidth for digital operation and 25kHz and/or 12.5kHz
channel bandwidth for analog operation. The repeater dynamically switches between
analog and digital modes based on the call it receives from radios. If an analog radio
transmits, the repeater switches to analog mode to repeat the analog call. However, the
repeater only repeats analog calls that are qualified by PL (DPL/TPL). If a digital radio
transmits, then the repeater switches to digital mode to repeat the digital call. While the
repeater repeats one analog call at a time, it can repeat 2 digital calls at a time, one on
each logical channel.
When a repeater repeats a new digital call that starts on one of the logical channels, the
repeater does not qualify any analog call including an emergency call until the digital call
(both the transmission and call hang time) is over and the corresponding channel hang
time has expired. Upon the expiry of channel hang time, only then does the repeater start
qualifying both analog and digital calls simultaneously. Similarly, if an analog call is being
repeated, the repeater does not qualify any digital call including digital data and
emergency calls on any of the two logical channels until the analog call is over and the
corresponding hang time has expired.
Analog console device(s) are supported only when the repeater has not qualified an OTA
digital call. Once a digital call has been qualified, an audible alert (channel busy tone) is
generated over the speaker and Rx audio pins on the 4-wire repeater interface, if the
analog console tries to key up to indicate that the channel is busy and that the console
access has been denied.
Dynamic Mixed Mode (DMM) is a repeater only configuration and the main functions of
this feature are:
• The system requires one pair of physical channels (one Tx frequency and one Rx
frequency) for both analog and digital calls, one MOTOTRBO repeater, and one set of
RF equipment (antenna, combiners, couplers, LNA, etc) to enable analog and digital
radio users to communicate.
• This configuration allows the user to have a mix of legacy analog radios and the digital
MOTOTRBO radios in a MOTOTRBO system.
• The repeater supports two independent time slots or logical channels within the
12.5kHz physical channel bandwidth while repeating digital calls. However, the
repeater supports one voice path (transmit and receive) on a 25kHz or 12.5kHz
channel while repeating analog calls.
Dynamic Mixed Mode does not support the following configurations/features.
• IP Site Connect configuration - This means that in Dynamic Mixed Mode, the
repeater can only repeat the digital calls Over-the-Air and cannot send the voice/
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16 System Feature Overview
data packets over the IP network. The status of the repeater and the control of the
repeater cannot be performed from a remote PC application like RDAC-IP.
• Capacity Plus configuration - This means that in Dynamic Mixed Mode, trunking
the logical channels of multiple MOTOTRBO repeaters as per Capacity Plus is not
supported.
• FCC Type-I and Type-II monitoring - Since FCC Type-I and Type-II monitoring are
not supported in single site analog operation in any of the earlier MOTOTRBO
releases, it is also not supported in Dynamic Mixed Mode single site operation.
• Transmit Interrupt feature - The Voice Interrupt, Emergency Voice Interrupt,
Remote Voice Dekey, and Data Over Voice Interrupt features are presently not
supported in Dynamic Mixed Mode systems.
• RDAC over IP feature - RDAC over local USB and connections via GPIO are
supported. RDAC over the network is NOT supported.
• Repeater Knockdown - In Dynamic Mixed Mode systems, this feature is not
supported during an ongoing digital transmission.
• PTT on a 4-wire interface - In Dynamic Mixed Mode systems, this feature is not
supported during a digital repeat operation.
4. When operating in IP Site Connect Mode, MOTOTRBO combines the logical channels of
multiple MOTOTRBO systems (operating in digital repeater mode at dispersed locations)
into one logical channel covering all locations. In this mode, repeaters across dispersed
locations exchange voice and data packets over an IPv4-based back-end network. There
are three main functions of this mode.
• To increase the RF coverage area of a MOTOTRBO system.
• To provide voice and data communication between two or more MOTOTRBO single
site systems located at geographically separate locations.
• To provide voice and data communication between two or more MOTOTRBO single
site systems operating in different frequency bands (e.g. 800/900 MHz, VHF, and
UHF).
The backend network of an IP Site Connect system is designed to work seamlessly with
internet connectivity provided by an Internet Service Provider (ISP). The system only
requires that one of the repeaters have a static IPv4 address, while the others may be
dynamic. Also, the system avoids the need for reconfiguration of a customer’s network
such as reprogramming of firewalls.
When a new call starts at one of the logical channel of a repeater, the repeater sends the
call to all the repeaters and all these repeaters repeat the call on their corresponding
logical channel. This allows a radio in the coverage area of any repeater to participate in
the call. Thus, the coverage area of an IP Site Connect system is the sum of the coverage
areas of all the repeaters. However, note that an IP Site Connect configuration does not
increase the capacity (i.e. number of calls per hour) of the system. The capacity of one
Wide Area Channel of an IP Site Connect system is approximately the same as that of a
single repeater working in digital repeater mode.
In an IP Site Connect configuration, MOTOTRBO radios support all the features that they
already support in digital repeater mode; with the exception of the Transmit Interrupt
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System Feature Overview 17
features, that are presently not supported on logical channels configured over wide area.
Additionally, the radios are capable of automatically roaming from one site to another.
The IP Site Connect configuration of MOTOTRBO does not require any new hardware
besides backend network devices such as routers. If a customer has multiple
MOTOTRBO systems working in digital repeater mode at dispersed sites and wants to
convert them into an IP Site Connect system then the repeaters and the radios should be
updated with new software and the repeaters need to be connected to an IPv4-based
backend network. It is possible to configure a repeater such that
• Both logical channels work in IP Site Connect mode (i.e. over wide area). Neither of
the logical channels are capable of supporting the Transmit Interrupt features in this
configuration. However, both are capable of repeating interruptible voice calls.
• Both logical channels work in digital repeater mode (i.e. single site over local area).
Both logical channels are capable of supporting the Transmit Interrupt features in this
configuration.
• One of its logical channels works in IP Site Connect mode (i.e. over wide area) and
the other logical channel works in digital repeater mode (i.e. single site over local
area). The logical channel operating in IP Site Connect mode (i.e., over wide area) is
not capable of supporting the Transmit Interrupt features in this configuration.
However, it is capable of repeating interruptible voice calls. The logical channel
operating in digital repeater mode (i.e., single site over local area) is capable of
supporting the Transmit Interrupt features.
MOTOTRBO has three security features in the IP Site Connect configuration.
• Provides the confidentiality of voice and data payloads by extending the privacy
feature, whether Basic or Enhanced, to cover the communication over the backend
network.
• Ensures that all the messages between repeaters are authentic.
• Supports Secure VPN (Virtual Private Network) based communication between the
repeaters for customers needing higher level of security (protection against replay
attack).
The IP Site Connect configuration of MOTOTRBO provides a mechanism and a tool to
remotely manage repeaters. The tool (called RDAC) receives alarms from all the
repeaters, helps in diagnosis of repeaters, and provides some controls over the repeaters.
5. When operating in Capacity Plus Mode, MOTOTRBO trunks the logical channels of
multiple MOTOTRBO repeaters (operating in digital repeater mode) at the same location.
This allows the radios to share the logical channels, resulting in less waiting time to
access the system and increased channel capacity for a given quality of service. Another
advantage is that the probability of all channels being busy at the same instant is low,
therefore the probability of a call being blocked is lower than when only one channel can
be accessed.
Capacity Plus is a single site trunking configuration of the MOTOTRBO system. In a
Capacity Plus configuration, all the “idle” radios (i.e. radios neither receiving nor
transmitting) are on an idle channel called the rest channel. Therefore, a new call always
starts on the rest channel. At the start of a call, the rest channel repeater selects one of the
idle channels as the new rest channel, informs the radios on the current rest channel
about the new rest channel, converts the current rest channel to a traffic channel, and
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18 System Feature Overview
starts repeating the bursts sent by the radio. The radios that are not participating in the call
(i.e. destination of the call is not of their interest) move to the new rest channel.
If the current rest channel is the last idle channel (i.e. all the other available channels are
in use), the current rest channel remains as the rest channel. The call starts on the
channel and non-participating radios stay on the channel. In this condition, nonparticipating radios indicate that the channel is busy via its yellow LED. If all channels are
busy and a radio user initiates a call, then the radio generates a distinct tone to indicate
that the system is busy. As soon as a channel becomes free in the Capacity Plus system,
the non-participating radios are informed, and move to the free channel.
At the end of the call (i.e. after the call hang time), the repeater also broadcasts the status
of all other available channels. This triggers any radio on the channel to move to the
current rest channel or to a channel where a Group Call of interest is active.
The Capacity Plus system has no central controller to manage the rest channel. The rest
channel is managed collectively by all the trunked repeaters. A trunked repeater
periodically informs the status of its channels to other trunked repeaters whenever the
status of its channels change. When a new rest channel is selected, the selecting repeater
informs all the other repeaters. The new rest channel is selected based on the following
conditions:
• At the start of a call, the repeater of the current rest channel selects the new rest
channel.
• On detection of interference or before starting CWID (i.e. BSI) transmission, the
repeater of the current rest channel selects the new rest channel.
• On detection of no rest channel (in the event of a failure of the current rest channel
repeater or the backend network), the repeater with the lowest ID selects the new rest
channel.
• When a call ends on a system, if a call is in progress on the current rest channel, then
the repeater of the current rest channel selects the new rest channel.
The Capacity Plus system does not require an exclusive control channel. The rest channel
changes on every call; in case of an interference or if the repeater becomes unavailable
due to failure. This results in the following advantages:
• Non-exclusive channels make it easier to satisfy regulator frequency coordination
(where exclusive use of channels is not possible).
• Capacity Plus does not use “request and grant” mechanism to allocate channels and
does not require any central controller to trunk the channels.
• The dynamic rest channel mechanism makes Capacity Plus very suitable for an
environment where channels are shared by multiple radio systems.
• The dynamic rest channel mechanism also improves the reliability of the Capacity
Plus system. In the event of a repeater failure, the other available repeaters
automatically reconfigure themselves and continue to work as the Capacity Plus
system.
The Capacity Plus system configuration of MOTOTRBO does not require any new
hardware apart from backend network devices such as routers. If a customer has multiple
MOTOTRBO systems working in digital repeater mode at the same site and wants to
convert to a Capacity Plus system, then the repeaters and radios should be updated with
the new software, and the repeaters need to be connected to an IPv4-based backend
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System Feature Overview 19
network. If one logical channel of a repeater is configured to the Capacity Plus mode, then
the other logical channel will also be in the same mode.
In a Capacity Plus configuration, MOTOTRBO systems support all previous digital
repeater mode features, with the exception of the following:
• Scan: Capacity Plus supports Group Scan but does not support scanning channels of
another system. As the radios are in a trunked system, scanning the Trunked channels
is not required.
• Emergency Revert Channel: Capacity Plus does not support a revert channel for
emergency because probability of all Trunked channels becoming busy is low. However,
reverting to an emergency group is supported. This promotes a centralized handling of
an emergency situation.
• IP Site Connect configuration: Capacity Plus is a single site system and therefore
does not support features related to IP Site Connect configuration such as wide-area
coverage and automatic roaming. However, a radio can be programmed with multiple
channels in multiple zones, one of which could be a Capacity Plus system, another an
IP Site Connect System, and others could be MOTOTRBO conventional channels or
Analog conventional channels.
• Impolite calls: Capacity Plus supports impolite emergency call and impolite
transmissions (i.e. Group members can transmit over an ongoing call). A new call
always starts on an idle channel and therefore, a radio does not start a non-emergency
call impolitely.
• Talkaround mode: A radio can have a talkaround personality but in Capacity Plus
mode, there is no talkaround option.
• Monitoring of channels status: Monitoring is important in a conventional system,
where a radio stays on a channel. In Capacity Plus, a radio moves from one rest
channel to another. Most of the rest channels are in an idle state and therefore,
monitoring is not necessarily needed.
• Fragmentation of a Data Packet: Capacity Plus does not fragment a data packet
before transmitting Over-the-Air. Thus, the size of an IP datagram (including IP and UDP
headers) should be less than the maximum size of the Packet Data Unit. The value of
the Packet Data Unit is a CPS programmable parameter with a maximum size of 1500
bytes.
• Option Board: If the Option Board feature is enabled for Capacity Plus, then the feature
is automatically enabled for all trunked and revert channels of a Capacity Plus system.
On a Capacity Plus personality, the Option Board is not aware of the transmit or receive
channel. Additionally, an Option Board does not use or create Virtual Personalities in a
Capacity Plus system. Hence, an Option Board will not be able to customize the current
working personality.
• Transmit Interrupt: The Voice Interrupt, Emergency Voice Interrupt, Remote Voice
Dekey, and Data Over Voice Interrupt features are presently not supported on Capacity
Plus systems.
Capacity Plus does not provide the following features:
• Coverage of multiple sites,
• Call queuing, priority, and preemption,
• Priority Monitor: Capacity Plus provides higher priority only to an All Call,
• Radio access control.
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Greater detail on system services available in direct-mode and repeater-based system
topologies is described in “System Components and Topologies” on page 113.
2.2.2 MOTOTRBO Supports Analog and Digital Operation
The MOTOTRBO system can be configured to operate in analog mode, digital mode, or in
Dynamic Mixed Mode. The system can consist of multiple repeaters. A single MOTOTRBO
repeater configured to operate in Dynamic Mixed Mode can dynamically switch between analog
and digital modes depending on the type of call it receives. A repeater in Dynamic Mixed Mode
system cannot be part of multiple repeater system in which the repeaters are connected over the
network for IP Site Connect or Capacity Plus operation.
MOTOTRBO portable and mobile radios can communicate in analog and digital. The mobile or
portable radio user selects the mode of operation (analog or digital), and physical and logical
channel using his channel selector knob (each channel selection position is configured for a
particular call type on either a digital channel that specifies both frequency and time slot, or an
analog channel that specifies both frequency and 25kHz or 12.5kHz bandwidth). Radio channels
are either analog or digital. This is configured by the CPS. The radio can scan between analog and
digital channels.
Greater detail on channel planning and configuration is provided in “System Design
Considerations” on page 175.
2.2.3 MOTOTRBO Channel Access
Channel access dictates what conditions a radio is allowed to initiate a transmission on a channel.
The channel access rules of MOTOTRBO are governed by the mobile and portable radios. It is the
radio’s responsibility to assess the state of the system, and utilize its channel access rules to
decide whether to grant the call to the user.
In repeater systems, it is the repeater’s responsibility to:
• Identify if a channel is busy, or
• Identify if a channel is idle, or
• Inform for which radio the channel is reserved.
The repeater does not block or deny any channel access from radios on its system, but will not
repeat transmissions from another system.
There are two main types of channel access in a MOTOTRBO system: Polite and Impolite access.
In the configuration software, channel access is referred to as the Admit Criteria. MOTOTRBO
supports the following Admit Criteria:
• Always: This criteria is often referred to as “Impolite” channel access, and can be
applied to analog and digital channels.
• Channel Free: This criteria is often referred to as “Polite to All”, and can be applied to
analog and digital channels
• Color Code Free: This criteria is sometimes referred to as “Polite to Own Color Code”
or “Polite to Own System”, and is applied only to digital channels.
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System Feature Overview 21
• Correct PL: This criteria is sometimes referred to as “Polite to Other System”, and is
applied only to analog channels. The radio checks for a PL match prior to allowing a
transmission.
Channel access methods must be specified for each channel in the radio CPS. The TX (Transmit)
parameters for each defined channel contains an “Admit Criteria” selection that must be set to one
of the values described above.
All these channel access options govern how standard group voice calls and private calls access
the system. Not all transmission types utilize these settings. For example, emergency voice calls
always operate impolitely. This gives emergency voice calls a slightly higher priority over existing
traffic on the channel. Data calls are always polite. Since a data call can be queued and retried, its
priority is considered lower than voice.
Note that a “polite” radio user attempting a voice call will be polite to data, but an impolite user may
not. Control messages (used for signaling features) are also always polite. The exception is the
emergency alarm. Emergency alarms are sent with a mix of impolite and polite channel access, in
order to optimize the likelihood of successful transmission.
When the Admit Criteria is either Channel Free or Correct PL, a configurable RSSI threshold is
provided per channel in the radio. If the received signal strength is less than the configured RSSI
threshold, the signal is considered as an interference and the radio gets channel access when the
user initiates a new call. However, if the received signal strength is greater or equal to the
configured threshold, the channel is considered busy and the radio does not get channel access
when the user initiates a new call. It is the responsibility of the site planner or the service provider
to set the RSSI Threshold to an appropriate value considering the RF interference and also ensure
that the desired signal strength is more than the configured threshold. The default value of RSSI
Threshold is -124 dBm. The configurable range is between -124 dBm to -80 dBm. When a value of
-124 dBm is selected, subscriber does not get channel access if carrier activity is detected due to
interference on the channel when the user initiates a new call. A value of -124 dBm is very
sensitive to RF interference.
When operating in IP Site Connect mode, the repeaters also check the channel for interference
before transmitting. This is required since even though the source radio checks the channel at one
site, it does not mean there is no interference at another site. Therefore, a repeater will check for
Over-the-Air interference before waking up and transmitting. The repeater always acts with an
Admit Criteria of Channel Free and has a configurable signal strength threshold. Note that
although one site may be busy, the other non-busy sites will continue with the call.
2.2.3.1 Impolite Operation (Admit Criteria of “Always”)
When configured for impolite operation, a radio does not check for an idle channel prior to allowing
a transmission. From the user’s perspective, the radio simply transmits when the PTT is pressed.
However, on a digital repeater channel, the radio checks if the repeater is hibernating.
Transmission will not proceed, if the repeater is hibernating and the radio is unable to wake it.
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NOTE: It is very important to note that when a radio is utilizing impolite operation, it is possible that
it is transmitting on top of another user’s transmission. This causes RF contention at the
target. When RF contention occurs between digital transmissions, it is impossible to
predict which signal is usable. If one transmission is much stronger than the other, it is
received instead of the weaker signal. But in most cases, the two transmissions on the
same frequency and time slot results in both transmissions being unusable. Thus, it is
recommended that only disciplined users are granted the right to use impolite operation.
Further, those impolite users are encouraged to utilize the busy channel LED on their radio
to determine, if the channel is idle prior to transmitting.
When operating in IP Site Connect mode, it is important to understand that impolite channel
access only occurs at the local site. If a call is taking place on the IP Site Connect system, and the
original source of that call is at the same site as the interrupting “impolite” radio, RF contention will
occur and it is unclear which source will be successful. If the original source of the call is at a
different site from the interrupting radio, the original call continues at all other sites except where
the interrupting radio is located.
When operating in Capacity Plus mode, the impolite operation is supported only in emergency
calls.
2.2.3.2 Polite to All Operation (Admit Criteria of “Channel Free”)
When configured for Polite to All operation, the radio checks if channels are idle or busy, prior to
allowing a transmission. The radio is polite to all analog or digital transmissions, another system’s
transmission, or other traffic on your system. This option is often used, when there are neighboring
communications systems, to prevent radio users from disrupting each other’s transmissions.
However, when this option is used, any strong signal on the channel blocks other users from
transmitting.
2.2.3.3 Polite to Own Digital System Operation (Admit Criteria of “Color Code Free”)
This criteria applies only to digital channels. When configured for Polite to Own Digital System
operation, the radio checks for an idle or busy channel, prior to allowing a transmission. This
operation is similar to the Polite to All operation with exception that the radio is not polite to analog
systems or other system’s transmissions. It is only polite to other traffic in its own system. This
option is often used when there are no neighboring communications systems, or when there is no
concern about interfering with radios in neighboring communication systems.
2.2.3.4 Polite to Other Analog System Operation (Admit Criteria of
“Correct PL”)
This criteria applies only to analog channels. When configured for Polite to Other Analog System
operation, the radio checks for an Idle or busy channel, prior to allowing a transmission. This
operation is similar to the Polite to All operation with exception that the radio is not polite to analog
systems with the same PL. It is polite to other system’s transmissions. The radio checks for a PL
match prior to allowing a transmission.
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System Feature Overview 23
2.2.3.5 Polite or Impolite, or Voice Interrupt While Participating in a Call (In
Call Criteria)
The In Call Criteria applies only when the radio is participating in an active call. The radio can
optionally allow others that are part of the call to transmit impolitely (Always), to automatically clear
the channel using the Voice Interrupt feature prior to beginning the voice transmission (Voice
Interrupt), or to follow the previously configured channel access (Follow Admit Criteria). If
configured for an In Call Criteria of Always, the user will receive a Talk Permit Tone when they
press the PTT while receiving a transmission for them. In other words, a radio has the ability to
transmit over another user while listening to their transmission. However, when this happens, the
other party does not stop transmitting and therefore RF contention can occur which may corrupt
both transmissions. The In Call Criteria of Voice Interrupt is an alternative to the In Call Criteria of
Impolite.
The Voice Interrupt option has advantages including the ability to avoid the previously described
RF contention issue by clearing the channel prior to beginning a transmission, which yields a
higher probability of successfully communicating with the intended target radio(s), as compared
with the RF contention encountered with impolite transmissions. However, Voice Interrupt has
disadvantages including a longer channel access time when an interruption is necessary, due to
the signaling having to complete the interruption and handoff.
If configured for an In Call Criteria of Voice Interrupt, the radio user receives a Talk Permit Tone
when PTT is pressed while receiving an interruptible voice transmission and the channel is
successfully cleared down. In other words, a radio user has the ability to clear the channel of
another user’s interruptible voice transmission before beginning their own voice transmission
when both radios are participating in the same voice call (e.g., both are members of the same
group during a group call, or both are participating in the same individual call). The radio user
whose transmission was interrupted, receives a Talk Prohibit Tone until the user releases the PTT.
If the channel is not successfully cleared down, the user typically receives a Channel Busy Tone
until the PTT is released.
NOTE: For the Voice Interrupt feature to operate consistently, all radios using the channel should
be provisioned with the ability to be interrupted. However, not all need to be provisioned
with the Voice Interrupt capability.
If some radios are provisioned without the ability to be interrupted (e.g., normally desirable for a
supervisor’s radio), then those transmissions cannot be interrupted and the radio user receives a
Channel Busy tone if the Voice Interrupt feature is attempted while receiving an uninterruptible
voice transmission.
If configured for Follow Admit Criteria and the previously configured channel access (Admit
Criteria) is set to either Channel Free or Color Code Free, the user will receive a Transmit Denial
Tone when they press the PTT while receiving a transmission for them. Users must wait until the
user stops transmitting and call hangtime starts before they are granted a transmission. Utilizing
the Channel Free Tone helps train users from transmitting too early. Although a setting of Always
may be useful for speeding up conversations for well disciplined users, it may cause undisciplined
users to “step over” other users. Therefore, it is recommended that most users are provisioned
with an In Call Criteria of Follow Admit Criteria.
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2.2.3.6 Repeater Wake-up Provisioning
When there is no inbound traffic for a specified duration (Subscriber Inactivity Timer), the repeater
stops transmitting and enters an inactive state. In this inactive state, the repeater is not
transmitting, but instead it is listening for transmissions. When the user or radio needs to transmit
through the repeater, the radio sends a wake-up message to the repeater.
Upon receiving the wake-up message, the repeater activates and begins transmitting idle
messages. The radio then synchronizes with the repeater before it begins its transmission.
The repeater wake-up sequence is configurable within the radio. The number of wake-up attempts
(“TX Wakeup Message Limit“) and the time between the attempts (“TX Sync Wakeup Time Out
Timer”) may be altered if required to operate with other vendor’s systems. It is recommended that
these values remain at default while operating on MOTOTRBO systems.
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2.3 MOTOTRBO Digital Features
2.3.1 Digital Voice Features
2.3.1.1 Group Calls
The digital group is a way of enabling groups to share a channel without distracting and disrupting
one another. Because two-way radios are well suited for “one-to-many” types of calls, the Group
Call is the most common call in a MOTOTRBO system. Hence, the majority of conversations takes
place within a group.
The Capacity Plus system allows a radio user to leave a Group Call and start another voice or
emergency or control call (e.g. Call Alert, Radio Check, Radio Inhibit/Uninhibit, etc.) while the radio
is busy listening in to a Group Call. The radio moves to the current rest channel and starts a new
call on the rest channel. If a user starts a non-emergency call when all channels are busy, then the
call fails, and the radio stays on the channel.
Individual radios that need to communicate with one another are grouped together, and configured
to be members of a group. A transmitting radio can be heard by all the radios within the same
group, and on the same logical channel (frequency and time slot.) Two radios cannot hear each
other, if they are on the same logical channel (frequency and time slot) but on different groups.
Two radios on different logical channels cannot hear each other, even if they are placed in the
same group.
In MOTOTRBO systems, capabilities for Group Calls are configured with the portable and mobile
radio CPS. The repeater does not require any specific configuration for groups. Radios can be
configured to enable the user to select among multiple groups using the radio channel selector
knob or buttons, or using the radio menu contacts list. Which group a radio user hears on a given
channel depends on a configurable parameter called the RX Group List. A call preceding tone can
be provisioned to alert the target user of the incoming Group Call. This can be enabled or disabled
per Group. An introduction to configuring Group Calls and RX Group Lists is provided in “System
Design Considerations” on page 175 of this document.
Groups are defined according to the organizational structure of the end user. When planning for
groups, customers should think about:
• which members of the functional workgroups in their organization that need to talk with
one another,
• how those workgroups interact with members of other workgroups, and
• how users will collectively share the channel resources.
Greater detail on the fleetmapping process is provided in “System Design Considerations” on
page 175 of this document.
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2.3.1.2 Private Calls
MOTOTRBO provides the capability for a user to place a Private Call (also known as an “Individual
Call”) directly to another radio, even if they are not in the same group. However, for this action to
take place both radios need to be on the same channel and time slot. This feature allows a radio
user to carry a one-to-one conversation that is only heard by the two parties involved. For
example, an employee may use a Private Call to privately alert a specific manager about a
security incident, rather than placing a Group Call that would be heard by the whole group. Though
Private Calls utilize the signaling capabilities in MOTOTRBO systems to govern which radios are
allowed to participate, the use of a Private Call does not necessarily imply the use of encryption or
scrambling.
Private Calls can be configured as confirmed or unconfirmed on a per channel basis. For
confirmed private calls, the calling radio transmits a short control signal message to the target
radio. This signaling verifies the presence of the target radio before being allowed to start the call.
The receiving user does not need to manually “answer” this signal, but rather the receiving radio
automatically responds to the setup request. Once the receiving radio replies to the setup request,
the initiating radio sounds a Talk Permit tone and starts the call. The receiving radio sounds a
Private Call indication to the user, prior to relaying the received voice. Once a Private Call is set
up, subsequent transmissions do not require the call setup messaging. For unconfirmed private
calls, the calling radio does not transmit any control signaling before being allowed to start the call.
Although there is no confirmation the radio is present on the system, an audible indication from the
target user may act as confirmation. For example, “Joe are you there?”, “Yes, go ahead.”.
It is important to understand the advantages and disadvantages of confirmed and unconfirmed
operation as it relates to performance. In general, confirming radio presence increases the setup
time (voice access time) of a private call since the user must wait for the control signaling to go
through the radio network before acquiring a talk permit tone. Although this may take more time, it
does guarantee that the target radio is present prior to providing the talk permit tone. When
operating on an IP Site Connect system that is connected through the public internet, this time
may be longer than when operating on a single site since the control messaging may be traversing
through the internet. If the target radio is scanning or roaming, the setup time of a confirmed
Private Call may increase due to the fact that the first control message may not successfully reach
the scanning or roaming radio. The second attempt, which contains a preamble, has a higher
likelihood of reaching the scanning or roaming radio.
Since unconfirmed Private Calls do not transmit any control signaling, the additional setup time is
not required and therefore the voice access time is shorter. Because setup messaging is not used
prior to starting the call, it is possible that scanning or roaming radios may arrive late to a call. This
could cause the user to miss the first few words of the transmission (no more than what is lost
while scanning for a Group Call). In addition, the user must utilize an audible acknowledgement to
validate presence when configured with unconfirmed Private Calls since no control messaging is
used to confirm radio presence.
In MOTOTRBO systems, capabilities for Private Calls are configured with the portable and mobile
radio CPS. The repeater does not require any specific configurations for Private Calls. Radios can
be configured to allow the user to select the recipient of a Private Call using the radio menu
contacts list. Private calls can also be mapped to a channel selection or a programmable button.
Users can also manually dial the destination radio ID with the radio keypad. This means a radio
can make a Private Call to any other radio that is on the channel, regardless of whether the radio
has created a CPS Private Call entry for the target radio. A call receive tone, or call preceding
tone, can be configured to alert the target user of the incoming Private Call. This can be enabled or
disabled per individual radio. Greater detail on the fleetmapping process that governs who is
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System Feature Overview 27
allowed to make Private Calls and to whom, as well as an introduction to the CPS configuration
section for Private Calls, is provided in “System Design Considerations” on page 175 of this
document.
2.3.1.3 All Call
All Call is a one way voice call between a privileged operator and all users on a logical channel.
The transmitting radio utilizes a special All Call group that every radio on the same system and
logical channel (regardless of group) will receive.
In a Capacity Plus system, all the radios (including radios on busy channels, except the
transmitting radio(s) and radios listening to emergency calls) listen to an All Call. The listening
radios on a busy channel may take up to 350 ms to leave their channels and enter the All Call late.
The transmitting radio on a busy channel only enters the All Call late, after finishing the ongoing
transmission. If a radio initiates emergency while participating in an All Call, then the emergency
transmissions are made on the rest channel and the radios interested to participate in the
emergency call, leave the All Call to join the emergency call.
Example: An All Call is occurring on Channel 1, and Channel 2 is the rest channel. The radio
initiating an emergency call leaves Channel 1, moves to Channel 2, and starts the
emergency call. The start of the emergency call is announced on Channel 1. This
triggers the radios that want to participate in the emergency call to leave Channel 1 and
move to Channel 2.
As an All Call is considered a one-way transmission, users cannot talk back to an All Call. If the
user transmits after receiving an All Call, he transmits using his currently selected group. An All
Call follows the Admit Criteria of the selected channel. More information on the Admit Criteria is
provided in “Channel Access Configuration” on page 257.
All Calls do not communicate across different time slots or channels within the system. The ability
to initiate an All Call is only programmed into radios that are used in supervisory roles. All other
radios monitor All Call transmissions by default. This feature is very useful when a supervisor
needs to communicate with all the users on a logical channel, rather than just a particular group or
individual.
In MOTOTRBO systems, capabilities for All Calls are configured with the portable and mobile
CPS. The repeater does not require any specific configurations for All Calls. Radios can be
configured to enable the user to select an All Call via the radio menu contacts list. All Calls can
also be mapped to a channel selection or a programmable button. A call receive tone, or call
preceding tone, can be configured to alert the target user of the incoming All Call. Greater detail on
the fleetmapping process governs who is allowed to make All Calls, as well as an introduction to
CPS configuration section for All Calls, is provided in “System Design Considerations” on
page 175 of this document.
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2.3.2 Transmit Interrupt
The Transmit Interrupt feature is a suite of features proprietary to Motorola. This feature generally
allows a radio to shut down an ongoing clear, basic privacy, or enhanced privacy interruptible voice
transmission, and potentially initiate a new transmission. Because this is independent of call type,
therefore it applies to Group Calls, Individual Calls, Emergency Calls and All Calls. This feature
also applies to individual calls that are initiated via remote monitor command, and group calls that
are initiated via emergency remote monitor. To support different use cases, Transmit Interrupt has
four unique variations:
• Voice Interrupt: This feature allows a radio that is unmuted to an interruptible voice call,
to stop the ongoing voice transmission and initiate its own voice transmission to the
same call membership. Voice Interrupt is typically used during a prolonged voice
transmission when “late-breaking” or urgent information becomes available, and it is
necessary to disseminate the information to the group as quickly as possible.
• Emergency Voice Interrupt: This feature allows a radio to stop any ongoing
interruptible voice transmission, and initiate its own emergency transmission.
Emergency Voice Interrupt gives a radio an improved access to the radio channel, in an
emergency condition.
• Remote Voice Dekey: This feature allows a radio to stop an ongoing interruptible voice
transmission. It is typically used by a supervisor to remotely dekey a radio that is
inadvertently transmitting (e.g., the PTT is inadvertently pressed for an extended period
of time) and occupying the radio channel.
• Data Over Voice Interrupt: This feature allows a third-party data application on an
option board or attached PC to control the radio in order to stop any ongoing
interruptible voice transmission and initiate its own data transmission. This feature is
useful in situations where data traffic is more important than voice traffic. Data Over
Voice Interrupt is not used by any data applications native to the radio (e.g., Text
Message, Location, and Telemetry do not use Data Over Voice Interrupt).
While receiving a Direct Mode transmission, a radio may use the Transmit Interrupt feature to
remotely dekey the transmitting radio and begin its own Direct Mode or Repeater Mode
transmission. Similarly, while receiving a Repeater Mode transmission, a radio may use the
Transmit Interrupt feature to remotely dekey the transmitting radio, and begin its own Repeater
Mode transmission. However, the radio may not use the Transmit Interrupt feature to remotely
dekey the transmitting radio’s Repeater Mode transmission and begin its own Direct Mode
transmission. This scenario is not supported because Transmit Interrupt dekeys only the radio’s
transmission within a channel (timeslot), but does not dekey the repeater which remains keyed on
the Direct Mode carrier frequency, and supports two channels (timeslots). The repeater is not
dekeyed because this may interfere undesirably with a call in the other channel (timeslot)
supported by that repeater.
Provisioning of the Transmit Interrupt feature in general, is separated into two basic categories:
1. Radios that have the ability for voice transmissions to be interrupted.
2. Radios that have the ability to initiate transmit interrupt commands.
NOTE: The radios may be provisioned with none, one, or both of these capabilities.
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System Feature Overview 29
There are a few important items to consider before provisioning of the Transmit Interrupt feature:
• The Transmit Interrupt feature is supported in digital direct mode, single site repeater
mode, and only local slots of the IP Site Connect mode. This feature is currently not
supported on Capacity Plus system configurations.
• Because the Transmit Interrupt features are proprietary to Motorola and use some
proprietary signaling (i.e., manufacturer-specific extensions that comply to the ETSI
DMR Tier 2 standards), non-Motorola radios may not be able to unmute to an
interruptible voice transmission and Motorola radios may not be able to interrupt a nonMotorola radio’s voice transmission. Hence, it is highly recommended to assign radios to
separate groups and/or channels. This classifies radios provisioned with Transmit
Interrupt capability from the radios that are not provisioned with the capability.
•In Direct Mode, Transmit Interrupt can typically clear an interruptible voice transmission
from the channel in less than two seconds. In Single Site Repeater Mode, Transmit
Interrupt can typically clear an interruptible voice transmission from the channel in less
than three seconds. The Transmit Interrupt feature provides one automatic retry in the
event that the first interrupt attempt fails due to corrupt signaling (e.g., RF coverage
degradation, signaling collisions with other radios, etc.). The retry essentially doubles
the times shown above. If the radio user still needs to interrupt after the failed retry, the
user needs to initiate another service request.
• VOX is not compatible with the Transmit Interrupt feature. Therefore, VOX is prevented
from operating when any of the Transmit Interrupt features are enabled.
NOTE: For the Transmit Interrupt feature to operate consistently, all radios using the channel
should be provisioned with the ability to be interrupted. If some radios are provisioned
without the ability to be interrupted (e.g. normally desirable for a supervisor’s radio), then
those radios’ transmissions cannot be interrupted.
2.3.2.1 Upgrading a System to be Transmit Interrupt Capable
There are several considerations when upgrading a deployed system that presently do not support
1
the Transmit Interrupt feature,
Firstly, for systems that use a XPR 8300 repeater, the repeater software version must be upgraded
to R01.06.00, or later.
Secondly, for systems that use a MTR3000 repeater, Transmit Interrupt is not supported.
For systems that do not use privacy exclusively (See “Voice and Data Privacy” on page 77), radio
transmissions with privacy disabled and interruptible voice enabled cannot be received by radios
using software versions before R01.06.00. For systems that use privacy exclusively, there are no
major concerns with software versions before R01.06.00 receiving radio transmissions with both
privacy and interruptible voice enabled; provided the older release supports the type of privacy
being used by the radio provisioned with software version R01.06.00 or later.
To minimize service disruption during the upgrade period, systems that do not use privacy
exclusively may be upgraded using the following approach:
to become Transmit Interrupt capable.
1. Systems that are running on software versions R01.01.00 – R01.05.00, or software version R01.06.00 or
later which has the Transmit Interrupt feature disabled in the CPS configuration, or non-Motorola
equipment, etc.
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30 System Feature Overview
• Provision new radios with software version R01.06.00 or later. Configure two channels;
one channel with Transmit Interrupt features enabled, and the other channel with all
Transmit Interrupt features disabled. During the upgrade, the channel with all Transmit
Interrupt features disabled is used.
• Upgrade previously deployed radios using software versions before R01.06.00 to
software version R01.06.00 or later, individually, and provision with the two channels
described above. The channel with all Transmit Interrupt features disabled is then used
during the upgrade.
• For systems that use a repeater, the repeater may be upgraded to be Transmit Interrupt
capable at any time. Finally, once all radios have been upgraded to software version
R01.06.00 or later, the channel with the Transmit Interrupt features enabled is used by
all radios on the system.
2.3.3 Digital Signaling Features
We have already described how digital calls utilize digital vocoding and error correction coding
processes, and that a given digital call occupies a single logical channel (frequency and TDMA
time slot). Within a given time slot, the digital call is organized into voice information and signaling
information. Included in the signaling information is an identifier used to describe the type of call
that is transmitted within the time slot (e.g. group call, all call, or private call). Signaling information
also includes identification information and/or control information, which is used to notify listeners
on a voice call of system events and status (e.g. the ID of the transmitting radio and the group ID).
Because this information is repeated periodically during the course of the call, this embedded
signaling allows users to join a voice transmission that is already in progress and still participate in
the call. This is referred to as Late Entry, and is an advantage over analog signaling schemes.
2.3.3.1 PTT ID and Aliasing
This feature allows the target radio to identify the originator of a call. If programmed with the radio
CPS (Customer Programming Software), a user friendly alphanumeric name or “alias” can also be
displayed. These user friendly aliases are also used when initiating voice calls and digital signaling
features. The alias information in the transmitting radio should correspond with the alias
information in the receiving radio. The transmitting radio ID is sent Over-the-Air and, if there is an
alias for that ID in the receiving radio, the receiving radio displays the alias. If no alias is configured
at the receiving radio for that ID, then only the transmitting radio's ID is shown.
2.3.3.2 Radio Disable (Selective Radio Inhibit)
This feature allows for a radio, typically in a supervisory role, to disable another radio via Over-theAir signaling. The disabled radio's display blanks and the radio is no longer able to make or
receive calls. The radio can still be turned on and off; this indicates that the radio has not failed, but
is disabled. Once disabled, a radio can only be enabled via the CPS, or by a Radio Enable
(Uninhibit) command from another supervisor radio. All radios are configured to accept inhibit
commands by default, but this can be disabled via the CPS. The target radio must be turned on
and be within coverage of the site it was disabled at for this action to be completed successfully.
This is important when disabling radios that roam or scan since the radio locks onto the site or
channel on which it was disabled, even after a power cycle. It may be required to return the radio
to the site in which it was disabled before it can receive an enable command Over-the-Air. This
may also be accomplished by communicating with the radio on the talkaround frequency of the site
in which it was disabled. The Radio Disable feature can be used to stop any inappropriate use of a
radio, or to prevent a stolen radio from functioning.
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System Feature Overview 31
In MOTOTRBO systems, Radio Disable is configured in the portable and mobile radios with the
CPS. To allow a radio to use this function, it must be enabled in the CPS “Menu” settings. To
permit (or prevent) a radio from receiving and responding to this command, go to the “Signaling
Systems” settings in the CPS.
2.3.3.3 Remote Monitor
The Remote Monitor feature allows a remote user to activate a target radio’s microphone and
transmitter for a period of time. A call is silently set up on the target radio, and its PTT is controlled
remotely without any indications given to the end user. The duration that the target radio transmits
after receiving a Remote Monitor command is set in the target radio through the CPS. When
receiving the Remote Monitor command, the target radio initiates a Private Call back to the
originator of the Remote Monitor command.
This feature is used to ascertain the situation of a target radio which is powered-on, but is
unresponsive. This is beneficial in a number of situations including:
•theft,
• incapacity of the radio user, or
• allowing the initiator of an emergency call to communicate hands-free in an emergency
situation.
In MOTOTRBO systems, Remote Monitor is configured in portable and mobile radio CPS. To allow
a radio to use this function, it must be enabled in the CPS “Menu” settings. To permit (or prevent) a
radio from receiving and responding to this command, go to the “Signaling Systems” settings in the
CPS. When a radio is configured to decode the remote monitor command, the duration that the
target radio transmits after receiving a Remote Monitor command is also set in the CPS “Signaling
Systems” settings of the target radio.
The Remote Monitor feature may be activated on a disabled radio. Remote Monitor could also be
programmed to be activated on radios that are in emergency mode only.
2.3.3.4 Radio Check
The Radio Check feature checks if a radio is active in a system without notifying the user of the
target radio. Besides the Busy LED, there is no other audible or visual indication on the checked
radio. The receiving radio automatically and silently responds with an acknowledgement to the
initiating radio.
This feature is used to discreetly determine if a target radio is available. For example, if a radio
user is non-responsive, Radio Check could be used to determine if the target radio is switched on
and monitoring the channel. If the target radio responds with an acknowledgement, the initiator
could then take additional action such as using the Remote Monitor command to activate the
target radio’s PTT.
In MOTOTRBO systems, Radio Check is configured in portable and mobile radio CPS. To allow a
radio to use this function, it must be enabled in the CPS “Menu” settings. All MOTOTRBO radios
will receive and respond to a Radio Check, i.e. this feature cannot be turned off in the CPS.
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32 System Feature Overview
2.3.3.5 Call Alert
The Call Alert feature allows a radio user to essentially page another user. When a radio receives
a Call Alert, a persistent audible and visual alert is presented to the user. The initiator of the Call
Alert is also displayed. If a user is away from his radio at the time of the reception, the alert
remains until the user clears the Call Alert screen. If the user presses the PTT while the Call Alert
screen is active, he starts an Individual Call to the originator of the Call Alert. For in-vehicle
applications, this is often used in conjunction with the Horn and Lights option. When a user is away
from his vehicle, a Call Alert can initiate the vehicle’s horn and lights to sound and flash, which
notifies the user to return to the vehicle and call the originator.
In MOTOTRBO systems, Call Alert is configured in portable and mobile radio CPS. To allow a
radio to use this function, it must be enabled in the CPS “Menu” settings. All MOTOTRBO radios
will receive and respond to a Call Alert (i.e. you cannot disable this feature by using the CPS).
2.3.3.6 Remote Voice Dekey
The Remote Voice Dekey feature allows a radio user to stop any interruptible voice transmission,
except for All Calls. This ability to remotely stop an interruptible voice transmission is provisioned
into the radio via the CPS and accessed via a programmable button.
NOTE: For the Remote Voice Dekey feature to operate consistently, all radios using the channel
should be provisioned with the ability to be interrupted. However, not all need to be
provisioned with the Remote Voice Dekey capability.
If some radios are provisioned without the ability to be interrupted (e.g., normally desirable for a
supervisor’s radio), then those radios’ transmissions cannot be interrupted and the radio user
receives a Remote Voice Dekey Failure Tone if Remote Voice Dekey is attempted while receiving
an uninterruptible transmission. The radios that are provisioned without the ability to be interrupted
(e.g., a supervisor’s radio) may still be provisioned with the Remote Voice Dekey feature, which
gives those radios the ability to interrupt another radio’s interruptible voice transmission.
For this feature, the initiating radio is not required to be a member of the voice call that is being
interrupted. Therefore, it is possible to interrupt a voice call, and then initiate a new call to a
different group or individual. Once the original voice transmission is terminated via the Remote
Voice Dekey feature, the interrupting radio user can initiate a new call via any of the available call
initiation methods.
When the programmable button is pressed and an interruptible voice transmission is on the
channel, the radio attempts to stop the interruptible voice transmission. If the radio succeeds at
interrupting the voice transmission, the radio user receives a Remote Voice Dekey Success Tone
when the channel is successfully cleared down. If the radio fails to interrupt the voice transmission,
then the radio user typically receives a Remote Voice Dekey Failure Tone. The radio user whose
transmission was interrupted receives a Talk Prohibit Tone until the PTT is released.
2.3.4 Digital Emergency
MOTOTRBO offers a variety of emergency handling strategies that will fit the customer’s
organizational needs. In its basic form, MOTOTRBO provides the ability for a radio user in distress
to send a confirmed emergency alarm message, and emergency voice to a user on a supervisory
radio. The emergency alarm message contains the individual radio ID of the initiator. Upon
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System Feature Overview 33
reception of an emergency alarm, the supervisor receives audible and visual indications of the
emergency and the initiating radio ID is displayed. Depending on configuration, emergency voice
may follow between the initiator and the supervisor. Once the supervisor handles the emergency
situation (i.e. solves the problem), he clears the emergency on the supervisor radio. Once the
initiator clears his emergency on the initiator radio, the emergency is considered over.
NOTE: A radio will not roam while reverted to a channel due to an emergency or when Active Site
Search is disabled. Reference the site roaming section for details on the interactions
between emergency and roaming.
Each mobile radio can program the Emergency Alarm to any of the programmable buttons,
whereas for the portable radio the Emergency Alarm can only be programmed to the orange
button. The Emergency Alarm can also be triggered externally through a footswitch for a mobile
application or any other applicable accessory. Pressing the emergency button causes the radio to
enter emergency mode, and begin its emergency process.
When a user presses the Emergency button, the radio gives audible and visual indications to show
that it has entered emergency mode. There is a CPS configurable option available, referred to as
Silent Emergency, which suppresses all indications of the emergency status on the user’s radio.
This feature is valuable in situations where an indication of an emergency state is not desirable.
Once the user breaks radio silence by pressing the PTT and speaking, the Silent Emergency
ends, and audible and visual indications return.
When the user’s radio is in the emergency mode, various other features are blocked that may
distract him from his communication with the supervisor. For example, the user will not be able to
initiate other features such as scan, private call, or other command and control functions.
Once the emergency is complete (e.g. turn off and turn on the radio, or long/short press of the
emergency button depending on the radio configuration) these abilities will return.
The emergency sequence is generally made up of two major parts:
• the signaling and
• the following voice call.
The emergency alarm is sent first, and depending on configuration is commonly followed up by an
emergency call.
An emergency alarm is not a data service, but rather a confirmed command and control signaling
that is sent to a group. More than one radio can be configured on the system to monitor that group,
and be designated to acknowledge emergency alarms for that group. These radios are considered
acknowledging supervisors. There is no user level acknowledgement. The supervisor radio
automatically acknowledges the emergency, and provides an alert to the supervisor radio user.
There are other radios that are designated to only monitor emergency alarms, but are not
permitted to acknowledge them; these users are commonly referred to as non-acknowledging
supervisors. Thus, sending the emergency alarm to a group allows for multiple supervisors to
receive the emergency alarm indication. It is important that only one acknowledging supervisor
should be configured per group and slot; otherwise there may be contention between the
acknowledgements.
The supervisors retain a list of received emergency alarms so that they can keep track of multiple
emergencies. Once cleared, the emergency alarm is removed from the list, and the next one is
displayed. These emergencies are displayed in a last-in-first-out sequence. The supervisor has
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34 System Feature Overview
the ability to hide the emergency alarm list, so he can contact service personnel to attend to the
received emergency situation. The channel where the emergency alarm was received is displayed
to aid the supervisor when changing channels.
If the user follows up the Emergency Alarm with a voice call while in the emergency mode, his
transmission contains an embedded emergency indication. Any radio user can be configured to
display this embedded emergency indication. Emergency calls are always processed with an
admit criteria of Always. This allows the emergency call to transmit regardless of the current
channel activity. If there is another radio currently transmitting, contention may occur.
The initiating radio supports a feature that is tied to silent emergency and the emergency call. The
“Unmute Option” prevents the radio from receiving voice traffic after initiation of a Silent
Emergency. In situations where an indication of an emergency state is not desirable, it is important
to be able to mute incoming voice, that may give away the initiators emergency state. Once the
user breaks radio silence by pressing the PTT and speaking, the radio returns to its normal
unmute rules.
Silent emergency and the unmute options have no effect on data. It is the responsibility of the end
user to make sure data is not sent to a terminal that would divulge any emergency state.
Transmission of data does not clear Silent Emergency.
The channel and group on which a user transmits his emergency is crucial to properly contacting a
supervisor. MOTOTRBO offers the ability for a user to transmit the emergency on a selected
channel or to automatically change to a predetermined channel to transmit his emergency.
Transmitting an emergency on a selected channel (referred to as a “tactical” emergency) is often
useful on small systems where there are only a few groups of users. Each group has its own
specified user that handles emergencies.
Automatically changing to a predetermined channel, referred to as “reverting”, is often useful in
systems that have a dispatch style emergency strategy. Users in various groups and channels are
configured to revert to a specific channel and group to process an emergency. This allows one
user to monitor an “Emergency” group, and all other users revert to him in case of an emergency.
This minimizes the possibility of supervisors missing emergencies on one channel, while
monitoring another channels. After the emergency is cleared, all users revert back to the selected
channel they were on before the emergency. In MOTOTRBO systems, the Emergency Revert
Channel is configured in portable and mobile radio CPS at the Digital Emergency Systems
settings.
The Capacity Plus system does not support a revert channel for emergency. The system does the
following to ensure that an emergency call should start on a channel where the user monitoring the
“Emergency” group is on.
• If at least one channel is idle, then the radio starts the emergency call on the rest
channel.
• If all channels are busy, then the radio moves to the current rest channel and transmits
the emergency call impolitely over the call in progress.
• The start of an emergency call is announced over all the busy channels. This allows a
listening radio that is interested in joining the emergency call, to leave its channel and
join the emergency call. A radio is interested in an emergency call if the emergency
group is either the Tx-Group, or is in the Rx-Group list of the radio. A radio listening to
an emergency call (e.g., e1) joins another emergency call (e.g., e2), only if the e2’s
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System Feature Overview 35
group has a higher priority than the e1’s group. The priority, in decreasing order, is first
the Tx-Group, followed by the group of the Rx-Group list of the radio.
NOTE: A radio does not provide any audible indication to the user when the radio switch channels.
However, the group display on the radio changes.
There are three major methods to process the emergency alarm and the emergency call; all are
configurable through the CPS. They are Emergency Alarm Only, Emergency Alarm and Call, and
Emergency Alarm with Voice to Follow.
2.3.4.1 Emergency Alarm Only
When configured for Emergency Alarm Only, the emergency process only consists of the
emergency alarm part. The number of emergency alarm attempts and their admit criteria are
configurable, and can even be set to retry indefinitely. The number of alarm attempts are controlled
by CPS parameters in the Digital Emergency System settings; these parameters include the
number of polite and impolite retries. The alarm is initially sent regardless of channel activity, and
once the configured impolite attempts are exhausted, the polite retries are executed when the
channel is idle. Emergency ends when:
• an acknowledgement is received,
• all retries are exhausted,
• the user manually clears the emergency, or
• the user pushes the PTT.
No voice call is associated with the emergency when operating as Emergency Alarm Only.
Pressing the PTT clears the emergency, and a standard voice call is processed.
2.3.4.2 Emergency Alarm and Call
When configured for Emergency Alarm and Call, the emergency consists of the emergency alarm
process followed by the ability to perform an Emergency Call. The number of emergency alarm
attempts and their admit criteria are configurable, and can even be set to retry indefinitely. The
alarm is initially sent regardless of channel activity, and once the configured impolite retries are
exhausted, the polite retries are executed when the channel is idle.
Emergency alarm stops when:
• an acknowledgement is received, or
• all retries are exhausted.
The radio still remains in an emergency state. Any follow up PTT initiates an emergency call, and
the call includes an embedded emergency indication. If the user presses the PTT before the radio
sends an emergency alarm, the radio stops sending the alarm, and starts the emergency call.
While in the emergency mode, all subsequent voice transmissions are emergency calls. The user
remains in emergency mode until he manually clears emergency. The only way to reinitiate the
emergency alarm process is to reinitiate the emergency.
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2.3.4.3 Emergency Alarm with Voice to Follow
When configured for Emergency Alarm and with Voice to Follow, the emergency consists of
sending a single emergency alarm, and followed by an automatic transmission of an Emergency
Call. This is referred to as hot microphone. The radio only sends one emergency alarm regardless
if there is channel activity, and then without waiting for an acknowledgement the radio immediately
activates the microphone and initiates an emergency call without the need of the user pressing the
PTT. The duration of the hot microphone state is configurable through the CPS in the Digital
Emergency Systems settings. This transmission is considered an emergency call, and therefore
includes the embedded emergency indication. Once this hot microphone duration expires, the
radio stops transmitting, but remains in the emergency mode. Any follow up PTT initiates an
emergency call, and includes the embedded emergency indication. The user remains in the
emergency mode until he manually clears his emergency. The only way to reinitiate the
emergency alarm and the hot microphone is to re-initiate the emergency.
It is important to note that when configured for Emergency Alarm with Voice to Follow, the radio will
continue to transmit voice for the duration of the provisioned hot microphone timer. Since voice
has priority over data, any data is queued while voice is transmitting, including the GPS update
that was triggered by the emergency. The GPS data cannot be delivered until after the radio stops
transmitting voice, and after the repeater hangtime has expired. The GPS data has no additional
priority over other data queued in the radios, or over any traffic on the channel. Therefore, its
delivery may be delayed if the radio in emergency has pending data queued or if the channel is
busy processing other traffic.
It is recommended when utilizing Emergency Alarm with Voice to Follow and GPS, that the hot
microphone timer be at maximum 30 seconds. There are a few reasons for this. First of all, data
messages will not stay in the queue for ever, 30 seconds is short enough so to give the GPS data
a chance to be transmitted without timing out. Second, if the hot microphone timer is longer than
30 seconds, and the GPS update rate is around the same value, then other GPS messages may
start to fill up in the queue while the voice transmission is processing. This not only occurs with the
radio in emergency, but with all other radios since the channel is busy. Therefore when the voice
call ends, all radios will be attempting to access the channel with their GPS data which increases
the likelihood of collisions and lost messages. Finally, it is important to understand that while the
user is transmitting due to its hot microphone timer, there is no way to communicate back to him.
Most users can explain their situation in less than 30 seconds and require some feedback from the
emergency dispatcher much sooner. That is why it is recommended to keep this value low and if
additional monitoring is required, the remote monitor feature can be utilized. Only use a long hot
microphone timer in specialized applications.
Also, since the emergency alarm itself is not acknowledged nor retried, its reliability is less than
that of the standard Emergency Alarm and Emergency Alarm Only and Call. These considerations
should be taken into account when choosing to operate with Emergency Alarm with Voice to
Follow.
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2.3.4.4 Emergency Voice Interrupt for Emergency Alarm
The Emergency Voice Interrupt feature, when enabled in a radio, is used during the initiation of an
emergency condition when an interruptible voice transmission is already taking place on the
channel.
When an emergency is initiated with Emergency Voice Interrupt enabled, the radio attempts to
interrupt an ongoing, interruptible voice transmission on the channel. The radio then uses the
established procedures for either Emergency Alarm or Emergency Alarm with Call, depending
upon the CPS configuration. For the Emergency Voice Interrupt for Emergency Alarm feature, the
radio is not required to be a member of the voice call being interrupted.
NOTE: For the Emergency Voice Interrupt for Emergency Alarm feature to operate consistently,
all radios using the channel should be provisioned with the ability to be interrupted.
However, not all need to be provisioned with the Emergency Voice Interrupt for Emergency
Alarm capability.
If some radios are provisioned without the ability to be interrupted (e.g., normally desirable for a
supervisor’s radio), then those radios’ transmissions cannot be interrupted and the radio user
instead transmits the Emergency Alarm in accordance with the configuration of the polite and
impolite Emergency Alarm fields in the CPS, if Emergency Alarm is attempted while receiving
another radio’s uninterruptible transmission.
If the interruption of the voice transmission is successful, the radio uses the established
procedures for either Emergency Alarm or Emergency Alarm with Call, depending upon the CPS
configuration, once the channel has been cleared. The radio user whose transmission was
interrupted receives a Talk Prohibit Tone until the PTT is released.
If the interruption of the voice transmission fails, the radio then uses the established procedures for
either Emergency Alarm or Emergency Alarm with Call, depending upon the CPS configuration.
However, the probability of success diminishes because the original voice transmission had not
been successfully cleared from the channel.
If the voice call on the channel is not transmitting an interruptible voice signal, the radio uses the
established procedures for either Emergency Alarm or Emergency Alarm with Call, depending
upon the CPS configuration, again with a lower probability of success.
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38 System Feature Overview
2.3.4.5 Emergency Voice Interrupt for Emergency Voice
The Emergency Voice Interrupt feature, when enabled in a radio, is used during the initiation of an
emergency voice transmission, primarily when an interruptible voice transmission takes place on
the channel and the radio does not belong to that voice transmission.
The radio attempts to interrupt the voice transmission, and then uses the established procedures
for Emergency Voice Transmissions, when all of the following conditions are met:
• Emergency Voice Interrupt is enabled.
• The radio is in an emergency condition (e.g., the designated Emergency button was
pressed previously).
• Another radio’s interruptible voice transmission is taking place on the channel.
• The radio in the emergency condition does not belong to the other radio’s voice
transmission (i.e., the radio in the emergency condition is not receiving the other radio’s
voice transmission).
• The radio user in the emergency condition requests an Emergency Voice Transmission.
The Emergency Voice Interrupt for Emergency Voice feature is not used when the radio belongs to
the voice call is being interrupted. Instead, when the radio belongs to the call on the channel (i.e.,
the radio that is receiving the voice transmission), the “In Call Criteria” is used rather than the
Emergency Voice Interrupt feature. This is because some systems may disallow radios to interrupt
any call to which they belong. In this case, the user must wait until the receiving transmission has
finished, before beginning their Emergency Voice transmission.
The Emergency Voice Interrupt for Emergency Voice feature is also capable of interrupting an All
Call provided the All Call is transmitting interruptible voice.
NOTE: For this feature to operate consistently, all radios using the channel should be provisioned
with the ability to be interrupted. However, not all need to be provisioned with the
Emergency Voice Interrupt for Emergency Voice capability.
If the radio succeeds at interrupting the voice transmission, the radio uses the established
procedures for Emergency Voice Transmissions, once the channel has been cleared. The radio
user whose transmission was interrupted, receives a Talk Prohibit Tone until the PTT is released. If
the radio fails to interrupt the voice transmission or the voice transmission is not interruptible, the
radio also uses the established procedures for Emergency Voice Transmissions. However, the
probability of success diminishes because the original voice transmission had not been
successfully cleared from the channel.
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2.4 MOTOTRBO Integrated Data
2.4.1 Overview
When performing in digital mode, any MOTOTRBO radio can be used as an integrated voice and
data radio, where the radio can send voice as well as data messages on a given logical channel.
This does not refer to data services like enabling users to surf the web, send video images, or
synchronize their office desktops. This is not the right technology for such bandwidth-hungry
applications. However, it is a great technology for productivity-enhancing applications like
messaging, location based services, simple database queries, bar code reading, and fill-in-theform type of applications. Additionally, it is built into the MOTOTRBO system, so there are no
monthly fees or dependencies on public carrier services, and customers control what applications
their users can access.
The MOTOTRBO system provides reliable data communications throughout the same areas
where the system provides readily usable voice communications. However, there is a trade-off
between the desired RF coverage area for data and the data throughput of the system. Extending
the range of a system's operation requires more data message retries to successfully complete
confirmed transactions, thus lowering throughput.
Integrating voice and data on the same channel brings several benefits. These include:
• Use of one RF channel for both voice and data.
• Use of one system infrastructure for both voice and data.
• Use of one subscriber to send and retrieve both voice and data messages Over-the-Air.
Integrating voice and data on the same channel also brings several considerations. These include
the following:
• Traffic loading
• Customer application requirements
• Contention of voice and data.
“System Design Considerations” on page 175 of this document provides practical guidance on the
above considerations.
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MOTOTRBO supports data services in a number of ways.
• MOTOTRBO allows radios to send “unit to-unit” and “unit-to-group” data packets. It
supports confirmed and unconfirmed delivery of a data packet. The table below shows
the confirmed and unconfirmed mode for all the software versions.
Call Type/Release
Unit-to-Unit
Unit-to-Group Unconfirmed
NOTE: If some of the radios in R01.05.00 and above, are still running on older software versions
like R01.00.00 or R01.01.00, then the radios must select the unit-to-unit data as confirmed
mode.
• MOTOTRBO also enables infrastructure and/or PC based applications by supporting
Internet Protocol (IP) addressing and IP packet data services. Rather than relying upon
external modems, MOTOTRBO radios can connect directly to computer equipment with
standard USB interfaces. This simplifies and lowers the cost of integrating with
applications, and at the same time expands the universe of potential applications that
organizations can deploy. Depending upon availability in your region, Motorola offers
two PC based MOTOTRBO applications:
• MOTOTRBO Location Services and
• MOTOTRBO Text Messaging.
• MOTOTRBO supports an Application Developers Program. This program includes a
complete application developer’s kit that fully describes interfaces for IP data services,
command and control of the radio, and for option boards that can be installed in the
radio.
R01.01.00 / R01.02.00 /
R01.03.00
Confirmed Confirmed CPS selectable
R01.04.00
Exception: In IP Site Connect, location
data is always sent unconfirmed.
R01.05.00 /
R01.06.00
for a personality.
Confirmed (by
default)
For some infrastructure based data applications, such as MOTOTRBO Location Services and
MOTOTRBO Text Messaging, the radio must first complete a registration process before data
messages can be exchanged between the radio and the infrastructure based application.
Registration has no impact on voice operation, aside from utilizing the same channel. Polite voice
calls will have to wait until an in-progress registration completes before it can use the channel,
while impolite voice calls can transmit on top of a registration transmission. A radio does not have
to register for voice services. A radio registers when the radio powers up in a data capable mode,
or changes into a data capable mode. A radio registers with a Presence Notifier, which is
incorporated within the MOTOTRBO Location Services and MOTOTRBO Text Messaging
applications, but may also be utilized with third
the data application servers that the registered radio is “on the system” and available for services.
In MOTOTRBO systems, the codeplug configuration determines whether or not a radio attempts to
register on the selected channel. This is defined via the ARS parameter which is enabled or
disabled through the settings within each channel. It must be set to enabled for those channels
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System Feature Overview 41
that are utilized for data communications with infrastructure based applications, such as
MOTOTRBO Location Services and MOTOTRBO Text Messaging.
2.4.2 Text Messaging Services
Multiple MOTOTRBO system components interact together to deliver text messaging services.
These include the built-in text messaging capabilities of MOTOTRBO subscriber radios and the
MOTOTRBO Text Messaging Services application. The MOTOTRBO Text Messaging Services
application in turn consists of several components, including the MOTOTRBO Mobile Text
Messaging Client used with fielded radios, the MOTOTRBO Text Messaging Client used with
dispatch-oriented positions, and the MOTOTRBO Text Messaging Server. The services provided
by each of these components are described in the following subsections.
Internet
Mobile Radios
Mobile Radios
Mobile RadiosMobile Radios
Tx
Tx
TxRxTx
USB
USB
Rx
Rx
Rx
USB
USB
USB
InternetInternet
Cell phone or e-mail
Cell phone or e-mail
addressable device
addressable device
USB
USB
USB
Portable Radios
Portable Radios
Portable RadiosPortable Radios
MOTOTRBO Text Messaging
MOTOTRBO Text Messaging
MOTOTRBO Text Messaging
Mobile Client
Mobile Client
Mobile Client
Tx
Tx
TxRxTx
Control Stations
Control Stations
Control StationsControl Stations
Rx
Rx
Rx
Figure 2-8 Text Messaging Services
Figure 2-8 shows a sample MOTOTRBO Text Messaging system configuration. See “System
Components and Topologies” on page 113 for more details on setting up your MOTOTRBO
system.
2.4.2.1 Built-In Text Messaging Service
The built-in text messaging feature allows MOTOTRBO portable and mobile radio users to send
and receive information in a text format. This feature provides a useful alternative to voice on the
MOTOTRBO system. The built-in text message service is fully accessed from the menu system on
MOTOTRBO radio models with keypads and displays. Some aspects of this service are also
available to non-display models.
Application Server
Application Server
•Presence Notifier
•Presence Notifier
•Text Messaging Server
•Text Messaging Server
•Text Messaging Dispatch
•Text Messaging Dispatch
•MCDD
•MCDD
USB
USB
LAN
LAN
LAN
LAN
USB
USB
USB
USB
USB
USB
USB
USB
Fixed Clients (Dispatcher)
Fixed Clients (Dispatcher)
MOTOTRBO Text Messaging Client
MOTOTRBO Text Messaging Client
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42 System Feature Overview
2.4.2.1.1 Services Provided to a Radio User
Using the built-in text messaging services, a radio user can create, send, receive, store and
display a text message. The following capabilities are included:
• A radio user can create a text message in one of two ways: Quick text or limited freeform text messages. Quick text messages are pre-defined using CPS. This allows a
user to choose from commonly sent messages without having to retype the content.
Once selected, the user is allowed to edit any part of the Quick text message prior to
sending. The CPS allows you to define 10 Quick Text messages.
• A radio user can select to send a text message to other radios. Messages can be sent to
an individual or to a group. When a message is sent to an individual, the sender
receives an acknowledgement once the recipient receives the message. If all delivery
retry attempts were exhausted, a failure indication will be generated. With messages
addressed to a group, the sender only receives confirmation that the message was
transmitted and does not receive confirmation from any of the intended recipients.
• When receiving a text message, the user is notified of a new message by an icon,
display string, and an audible tone if enabled in the codeplug via the CPS.
• Messages are received only if the radio is currently in digital mode of operation. A radio
user should enter scan mode to receive messages if multiple channels are being
utilized. System planning considerations associated with data and scan are discussed in
“System Design Considerations” on page 175 of this document.
• A user can store up to 30 received or sent text messages at a time. The user is notified
once the Inbox and sent folder storage becomes full. Once full, subsequent new
messages automatically cause the oldest messages to be deleted. Messages are not
deleted when the radio is turned off.
• A user can store up to 30 draft text messages in the Drafts folder at a time. Once full,
subsequent new drafts automatically cause the oldest draft(s) to be deleted. A user can
opt to Send, Edit, or Delete the drafts in the Drafts folder. The user can opt to Save a text
message that is being written or edited to the Drafts folder. If a high priority event causes
the radio to exit the text message editing screen, the current text message is
automatically saved into the Drafts folder. A draft that is sent is deleted from the Drafts
folder and stored to the Sent folder.
• The user can scroll through messages and select any message to read, reply to,
forward, save or delete.
2.4.2.2 MOTOTRBO Text Messaging Application
Depending upon availability in your region, Motorola offers MOTOTRBO Text Messaging, a
Windows PC-based application. It extends the system’s text messaging services to mobile and
central dispatch PC users. It also provides access to an important additional service: e-mail
messaging to radio users. The MOTOTRBO Text Messing application consists of the Text
Messaging Server, the Dispatch Text Messaging Client, and the Mobile Text Messaging Client.
2.4.2.2.1 Services Provided to a Radio User
Leveraging on the built-in text messaging services, a user can create, send, receive, store and
display a text message. The capabilities include the same ones available for “Built-In Text
Messaging Service” on page 41.
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System Feature Overview 43
• E-mail text messaging. A user is capable of sending and receiving text messages to and
from any pre-configured e-mail address. These pre-configured e-mail addresses must
be configured in the radio using the CPS and also in the Text Messaging Server. Thus,
the user can select e-mail addresses from the radio contacts menu, and send short
messages to any of those addresses.
• E-mail text messaging is only available to users when the radio is configured to interact
with the MOTOTRBO Text Messaging Server application.
• Both the radio and the application server must be configured for e-mail. Greater detail is
provided in “System Design Considerations” on page 175.
2.4.2.2.2 Services Provided to a Mobile Client
A Mobile PC user is located in the field and utilizes the MOTOTRBO Mobile Text Messaging Client
application to create and view the text messages. In MOTOTRBO systems, portable or mobile
radios can be configured through the CPS to route text messages to an attached mobile PC user.
The services offered by the text message mobile clients are as follows:
• Direct Routing – The mobile client provides the ability to text message other mobile
clients or radio users without going through the text messaging server, provided they are
on the same channel as the originating mobile client. This is also applicable if the
destination mobile clients or radios are scanning the channel that the originating mobile
client is on.
• Indirect Routing – The mobile client sends all text messages for e-mail and dispatch
destinations through the MOTOTRBO Text Messaging Server. The Text Messaging
Server can route the text message to a destination radio that is on a different channel.
• Extended Messaging Length – The Mobile client application user interface contains
two messaging composition panes; one for sending short messages to radio
destinations and the other for long messages to e-mail, dispatch destinations, and other
mobile clients. Text messages of up to 681 characters are supported.
• Local mailbox storage – The mobile client provides individual access to the local
storage of mailboxes.
2.4.2.2.3 Services Provided to a Dispatcher
A PC-based Dispatcher utilizes the MOTOTRBO Text Messaging Client and is connected to the
text messaging application server, either on the same machine or on the same Local Area
Network.
The services offered by the MOTOTRBO Text Messaging Client are as follows:
• Full Messaging Features – The local clients provide services such as Send/Reply/
Forward text messages to radio users, dispatch users and e-mail destinations. The
clients also support common mail folders such as Inbox, Outbox, Sent Items, Trash,
Drafts, and addressing from Address Books.
• Group Messaging – The local client is capable of sending messages to a group of
users (system groups), in addition to Text Groups which serve as customized
distribution lists.
• Extended Messaging Length – The local client application user interface contains two
messaging composition panes; one for sending short messages to radio destinations
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44 System Feature Overview
and the other for long messages to e-mail and dispatch destinations. Text messages of
up to 681 characters are supported.
• Support for Workgroups – Workgroups allow multiple individuals to send/receive
messages as a common dispatcher entity simultaneously. This provides a central
storage of Inbox and Sent Items mailboxes on the server for shared access among
users of same workgroup.
• Presence Status – The local client provides the dispatch user with the display of the
presence status for all radios of interest.
2.4.2.2.4 Services Provided by the MOTOTRBO Text Messaging Server
Application
The backbone of the MOTOTRBO text message application is the server application. It is located
on the customer’s Local Area Network (LAN). The server application sends, receives, and stores
the text messages that involve the dispatcher clients, mobile clients, and e-mail addresses.
The services offered by the MOTOTRBO text message server application are as follows:
• Communication gateway – The server acts as a gateway between the radios on the
system and the dispatcher clients. Configurable parameters within the codeplug include
the number of retries desired, and the duration between attempts.
• E-mail Gateway (SMTP) – The server provides the functionality of an e-mail server
using Simple Mail Transfer Protocol (SMTP). This enables text messaging users across
the MOTOTRBO system to communicate with an e-mail user located anywhere on the
internet. The e-mail addresses which a radio user wishes to use must be configured on
the server application for proper routing. Alternatively, a radio user can send a text
message to the dispatcher requesting that the message be forwarded to an e-mail
address.
• Presence Notification – The Presence Service notifies a subscribing text message
server application when a radio powers on/off, thus providing the status of radios to
Dispatch users. When utilizing the Presence Services, the text message server
application does not send any text messages to a user that is known to be absent from
the system. To preserve bandwidth, such message are discarded, and a failure
notification is returned to the original sender. Group messages do not receive a failure
notification; group messages are sent as unconfirmed messages.
• Central Device Management – The server provides a central configuration point for all
text messaging client address books.
• Authentication – The server provides an authentication gateway for dispatch users
during login to their clients.
• Management of Messaging Data – The server provides a central storage location for
shared mailboxes for dispatch users and the management of concurrent access for
these mailboxes. The archiving and backup of dispatch user mailboxes and the logging
of message exchanges on all interfaces are also provided.
2.4.2.3 Services Provided to a Third Party Text Message Application
Motorola provides an Application Development Kit (ADK) which documents how a text message
application interfaces with the text message protocol used for MOTOTRBO. A list of available
ADKs is available on page 109 of this manual.
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2.4.3 Location Services
GPS Radios
GPS RadiosGPS Radios
GPS Radios
GPS RadiosGPS Radios
Rx
Rx
Rx
Tx
Tx
TxRxTx
Tx
Tx
TxRxTx
Rx
Rx
Rx
Control Stations
Control Stations Control Stations Control Stations
Application Server
Application Server
Application Server
• Presence Notifier
• Presence Notifier
• Presence Notifier
• Location Server
• Location Server
• Location Server
• Location Dispatch
• Location Dispatch
• Location Dispatch
LAN LAN LAN
Fixed Clients (Dispatcher)
Fixed Clients (Dispatcher)
MOTOTRBO Location Client
MOTOTRBO Location Client
Figure 2-9 Location Services
The MOTOTRBO location feature allows a dispatcher to determine the current location of a radio
on a display map. The dispatcher can obtain the radio’s location alone (latitude/longitude) or the
location combined with other information about the environment (horizontal speed, direction, etc.)
that allows value-added services, such as tracking of resources.
MOTOTRBO systems enable location services via two complementary functions. First, the
MOTOTRBO mobile and portable radio portfolio includes models that are equipped with a built-in
GPS receiver. The acquisition of location data is done by a GPS receiver inside the radio and is
dependent on the GPS receiver receiving accurate signals from the earth-orbiting Global
Positioning System (GPS) satellites. However, the GPS receiver may not work well indoors or in
environments where the sky is largely obscured. Using the integrated data services capability of
the MOTOTRBO system, GPS equipped mobiles and portables are able to transmit their location
coordinates, over the radio system, to a receiving application that displays the radios’ geographic
locations on a high resolution map. This receiving application is the second part of the system.
NOTE: Depending upon availability in your region, Motorola offers the MOTOTRBO Location
Services application.
Third party location services applications are also supported. For more information regarding third
party applications, please see “Application Developer Program (ADP)” on page 107.
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46 System Feature Overview
2.4.3.1 Performance Specifications
GPS Transmitter Portable Mobile
TTFF (Time to First Fix) Cold Start < 2 minutes < 1 minute
TTFF (Time to First Fix) Hot Start < 10 seconds
Horizontal Accuracy < 10 meters
Note: Accuracy specifications are for long-term tracking (95th percentile values > 5 satellites visible at
a nominal -130 dBm signal strength).
The definitions for some of the terms stated in the table above are as below:
• Cold start – A cold start scenario occurs when the radio is first powered up, and the
GPS receiver is attempting to acquire its first position lock. In this scenario, the GPS
receiver only has a valid almanac stored; it does not have any valid satellite ephemeris
data nor valid real-time clock synchronization. Almanac data is stored in a non-volatile
(persistent) memory, and is valid for approximately one year. The GPS receiver regularly
updates the almanac data; therefore it will always be valid unless the radio is powered
off for more than one year. The almanac data provides a mapping of the GPS satellites’
position in the sky in relation to a real-time clock.
• Hot start – A hot start scenario occurs when the GPS receiver attempts to acquire a
new location fix after a previous fix had occurred recently. In this scenario, the GPS
receiver has valid satellite ephemeris data, a valid almanac, and valid real-time clock
synchronization.
• TTFF – Time to First Fix indicates the time the GPS receiver takes to determine its first
or subsequent position lock. This is determined largely by the time taken to download a
full satellite ephemeris or satellite orientation packet with a data rate of 50 bits per
second (bps), as well as, how long it takes for the GPS receiver to reach the relevant
satellite in its scan list. In a cold start, the scan list includes all of the 24 orbiting
satellites. The GPS receiver samples each satellite for a certain amount of time to
determine if it is visible or not before moving to the next satellite. The receiver continues
to do this until it detects a certain number of visible satellites and can determine an
approximate location, thus helping the receiver to truncate the scan list. In a hot start,
the receiver already has most, if not all, the data needed to calculate its position.
Therefore, no scanning is needed and minimal downloading is necessary to calculate
position, resulting in a lower time to acquire a positional fix.
• Horizontal Accuracy – Horizontal Accuracy indicates a radius length from the reported
point location. The latitude and longitude reported is equivalent to a point in the center of
a circle, with the horizontal accuracy value as the radius of the circle. The true position
should be within this location range.
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System Feature Overview 47
2.4.3.2 Services Provided to a Radio User
When the location service is disabled, the radio does not provide any location updates to a
location application server. An icon is displayed on the radio if the location service is enabled. The
absence of this icon indicates that the location service is disabled. The icon shows a full satellite
dish when good GPS signals are detected and an empty satellite dish when the radio is receiving
poor GPS signals.
Good Signal Poor Signal
The radio does not display its current location on its screen. With the exception of pressing the
Emergency button, a radio user cannot trigger a location update to a location application server. In
general, the radio user does not have to take any action in this process; the radio transmits the
location coordinates automatically over the system.
2.4.3.3 Services Provided to a Location Application
For all the services, a location application server is required to send an explicit request to the
radio. A radio does not provide unsolicited location update to a location application server. When
the radio turns on and/or selects a properly configured channel (i.e. the previously mentioned
“ARS Parameter”), the radio registers with the presence service. The location application thus
learns that this radio is on the air, and will make an explicit request for location updates if it is
configured to track the location of the radio.
Disabled
no icon
The GPS equipped radios transmit an update of their location coordinates over the radio system in
response to 3 service methods.
• Single Location Update – The location application server wants to know the current
location of a radio user. In this case, the application sends a request for a single location
update.
• Periodic Location Updates – Single location update is used to track the location of a
radio user by a location application server, but is an inefficient use of air interface.
Location tracking allows a location application server to periodically get the location of a
radio user by sending a single location request that contains the time interval between
updates. The radio continues to update its location periodically at the specified time
interval until the request is cancelled by the location application server. The location
tracking application can configure the radio to provide updates as frequently as once
every 10 seconds. The default value is once every 10 minutes. The rate of update is
configurable in increments of 1 second and must be matched with the resource
capabilities of the radio system and the needs of the end-user. This is discussed further
in “System Design Considerations” on page 175.
• On Emergency – A radio will send its location after the user triggers an emergency
alarm or an emergency alarm and call request. The location update is sent only to the
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48 System Feature Overview
location application server which had previously sent an active location request for
location updates from that radio upon an emergency event. This location update is sent
by the radio only after the processing of emergency is completed. For example, for
Emergency Alarm with Call, the location data is only sent after the emergency alarm is
acknowledged and the initial emergency call is completed. This happens because the
location data is sent as a data burst which has lower priority than the voice call.
2.4.3.4 Services Provided by the MOTOTRBO Location Services Application
The MOTOTRBO Location Services application consists of a server called MotoLocator and a set
of clients called Location Clients. The MotoLocator server requests, receives, and stores the
location data of the radios. The Location Clients get the location data from the MotoLocator server
and display the radios’ locations on a map.
The services offered by the MotoLocator are as follows:
• Tracked radio management: MotoLocator provides a way to edit (insert and delete) the
list of the radios that it is currently tracking. It also allows modifying the attributes of
those radios (e.g. a unique identifier and the name of the radio) and the parameters
associated with the tracking of a radio (e.g. elapsed time or distance after which the
location is sent by the radio, and content of the location data).
• Storage of Location Data.
• Viewing of Location Data: MotoLocator provides a user interface to view the current or
historical location data of a radio.
• Radio Group Management: This service allows grouping of a set of radios, so that they
can be tracked together.
• Resource Management.
• Dispatcher Capability Management: This service allows configuring the radio groups
that a dispatcher can track.
The services offered by a Location Client are as follows:
• Display location on a map of targeted radio/group/resource including polling and
historical data.
• Map Operations: This feature allows zooming, panning, and scrolling of the map on
display. It also allows adding and editing the point of interests, and selecting the layers
of the map for display.
• Map Data Setup: This feature allows changing the setting of a map by allowing
selection of the layers of the map, allowing geocoding, and customization of the search.
• Searching: This feature allows searching the map based on the address or common
place (e.g. hospital, or school), or point of interest.
• Routing: This feature allows finding the shortest path between two points on a map.
• Geofencing: This feature allows the defining of multiple boundaries. A notice is
provided, and a tone is heard when a resource enters or leaves any defined boundary.
The notice indicates the device that has crossed the boundary, the boundary name (if
the radio has more than one active boundary), and also if the device has entered or left
the boundary.
• Text Messaging: A Location Client integrates with MOTOTRBO Text Messaging Client
for sending and receiving text messages to/from other resources.
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2.4.3.5 GPS Revert Channel
The GPS Revert Channel feature allows system operators a configurable option to off load radio
transmitted location updates onto a programmed digital channel that differs from the digital
Selected Channel. This feature effectively removes Location Update traffic from the Selected
Channel in order to free up that channel to accommodate increased voice loads and/or to enhance
the user experience by reducing the number of channel busies during voice call requests. This
feature also allows a large group to communicate on a single voice channel while sending location
updates on multiple GPS Revert Channels to accommodate larger Location Update loads. This
increases the Location Update throughput associated with radios belonging to a single group.
Each channel programmed into the radio has a configurable CPS option to designate the GPS
transmission channel on which it transmits Location Update messages. The CPS options for the
GPS transmission channel are Selected, All, and None. Choosing Selected means that the GPS
updates are transmitted on the current channel. In the case of All, a single channel must be
chosen from the list of all channels. This chosen channel is known as the GPS Revert Channel
and this is where GPS updates are transmitted on. It is understood that there may be instances
when the radio is known to be out of range of any control station accepting location updates. In
order to extend battery life, minimize time away from the Selected Channel, and/or to efficiently
use frequency resources in these situations, the radio can also be configured to disable the
transmission of Location Update messages on a per channel basis by using the selection None. It
should be noted that a radio will be shown as present to the dispatcher when a radio is switched
from a GPS enabled channel to a GPS disabled channel until the presence indication duration is
exceeded.
To configure the radio to support location updates, there are a few parameters that must be
managed correctly. How these parameters interact to dictate the radio’s performance is shown in
the table that follows. These parameters are the radio wide GPS setting that resides in the General
Settings CPS folder, and the ARS and GPS Revert settings that are present for each channel
defined in CPS. In this case the channel being defined is titled “Channel1”. Also, in the case where
a GPS Revert Channel (GPS1) is selected, this requires that GPS1 has already been defined as a
channel in CPS.
Channels:
General
Settings: GPS
Zone1
Channel1
ARS
Not Enabled Not Enabled Not Selectable
Not Enabled Enabled Not Selectable
Enabled Not Enabled Not Selectable
Channels:
Zone1
Channel1
GPS Revert
Result
GPS Chip: Disabled
Presence: Disabled
Location: Disabled
GPS Chip: Disabled
Presence: Enabled
Location: Disabled
GPS Chip: Enabled
Presence: Disabled
Location: Disabled
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50 System Feature Overview
Channels:
General
Settings: GPS
Zone1
Channel1
ARS
Enabled Enabled None
Enabled Enabled
Note: Not Selectable means the setting cannot be configured as the option is grayed out.
Channels:
Zone1
Channel1
GPS Revert
Selected (Channel1)
GPS1
Result
GPS Chip: Enabled
Presence: Enabled
Location: Disabled
GPS Chip: Enabled
Presence: Enabled
Location: TX on Channel1
GPS Chip: Enabled
Presence: Enabled
Location: TX on GPS1
2.4.3.6 Data Revert Channel
A Capacity Plus system extends the “GPS Revert Channel” feature to the “Data Revert Channel”
feature. This feature is available only in Capacity Plus mode as a configurable option. The Data
Revert Channel feature allows system operators to offload all data messages from radios to a
Server (e.g. registration messages, location responses, text messages to the Server, and their
Over-the-Air acknowledgements, etc.) onto programmed digital channels (called Data Revert
Channels). Data messages (including their Over-the-Air acknowledgements) from radio-to-radio
and from the Application Server to radios are always sent over the Trunked channels.
The Data Revert Channel feature is optional. In the absence of this feature, data messages are
sent over the Trunked channels. This feature should be used when there is a need to reduce data
traffic from the Trunked channels. Data Revert Channels will free up the Trunked channels and the
Trunked channels can accommodate increased voice loads. This also enhances the user
experience by reducing the number of busy channels during voice calls.
Data Revert Channels are exclusively used by the system for transporting data packets. They are
not used for voice communication. As Data Revert Channels offload most of the data
communication from the Trunked channels, they facilitate more voice communication over these
channels. Data Revert Channels are especially useful for transporting location responses.
Each channel programmed into a radio has a configurable CPS option to designate the GPS
transmission channel on which the radio transmits Location Update messages. The CPS options
for the GPS transmission channel are Trunked, Revert, and None. Choosing Trunk ed means that
the data messages to the Server are transmitted on the rest channel. In the case of Revert, data
messages to the Server are transmitted over one of the revert channels that are programmed into
the subscriber. There may be instances when the radio is known to be out of range of any control
station accepting location updates. In order to extend battery life, minimize time away from the rest
channel, and/or to efficiently use frequency resources in these situations, the radio can also be
configured to disable the transmission of data messages on revert channels by using the selection
None.
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To configure a radio to support data messages, there are a few parameters that must be managed
correctly. How these parameters interact to dictate the radio’s performance is shown in the table in
section 2.4.3.5 “GPS Revert Channel”.
2.4.4 Telemetry Services
The MOTOTRBO radios incorporate telemetry functionality that is only supported in the digital
mode of operation. Both the MOTOTRBO portable and mobile radio support General Purpose
Input/Output (GPIO) lines on the radio accessory connector.
With this telemetry functionality, the originating radio can send a telemetry command to another
radio at the press of a programmable button. Telemetry commands instruct GPIO pins on the
target radio to be set, clear, toggle or pulse. The telemetry commands can also be used to query
the status of GPIO pins at the target radio.
At the receiving end, the basic built-in telemetry functionality allows the target radio to translate the
received telemetry command and to trigger GPIO action. It also enables the target radio to display
a programmed Text Status Message or act on a telemetry command received from the originating
radio responding to an event at the originating radio's GPIO pins. The Telemetry Text Status
Message is provisioned in the source telemetry radio and is displayed as a popup alert at a target
radio via the telemetry application. Since the Telemetry Text Status Message is not sent as a
standard text message, it is not saved in the Inbox or indexed. Furthermore, its target can only be
another radio since it must be received and processed by the telemetry application within the
radio.
It is possible for the message to be forwarded to an external computer connected to the radio, or
the option board, where a customer supplied application could monitor and take an action.
MOTOTRBO provides a telemetry interface for third party telemetry applications. Further
information is available in the Telemetry Services ADK listed under “MOTOTRBO Applications
Interfaces” on page 107.
Telemetry Over-the-Air signaling utilizes the data service similar to the way that text messaging
works. It can co-exist with voice and text messaging. If telemetry messages are expected to occur
often, for example 30 radios sending telemetry once every 5 minutes, this may affect performance
of other services on the channel. This should be taken into consideration when determining the
data load versus quality of service of a channel.
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2.4.4.1 Physical Connection Information
The MOTOTRBO portable offers three GPIO pins, and the MOTOTRBO mobile offers five GPIO
pins for telemetry. These GPIO pins can be set to high or low, toggled, or pulsed for a configured
duration. A pin can be configured to be active high or active low. It is recommended to use an ACpowered MOTOTRBO mobile for most extended telemetry applications. Motorola does not
currently offer external hardware for telemetry configuration.
The GPIO lines have a 4.7k ohm pull-up resistor tied to a regulated 5 V
radio. The regulated supply remains on as long as power is supplied to the mobile, even if the
mobile is turned off so the pull-ups are active even when the radio is off.
When configured as input, the voltages of the GPIO lines should be within the range of 0 V
5.5 V
.
DC
•0 V
• 2.2 V
to 0.8 VDC are interpreted as low level
DC
to 5.5 VDC are interpreted as high level
DC
When configured as output, the GPIO will be able to source a current of 1mA maximum at the
following levels:
• 4.7 V
•0 V
to 5.5 VDC for a high level
DC
to 0.8 VDC for a low level
DC
2.4.4.2 Telemetry Examples
See section 3.2.1.1.2 and section 3.2.2.1.2 for diagrams and descriptions of the following simple
telemetry examples in both direct and repeater mode.
• Send Telemetry Command from Radio to Another Radio to Toggle an Output Pin
• Send Telemetry Message from Radio to Another Radio when Input Pin State Changes
• Send Telemetry Command to Toggle an Output Pin from Radio to Another Radio when
Input Pin State Changes
supply within the mobile
DC
DC
to
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2.4.5 Data Precedence and Data Over Voice Interrupt
Data applications on the internal option board, or running on an attached PC, are able to request
priority treatment of data messages, and Data Over Voice Interrupt independently. To facilitate this,
the data application designates the precedence of each data message as being Immediate,
Priority, or Routine. When the radio receives a data message for transmission from an internal
option board or attached PC application, the radio determines the precedence requested for the
data message, and processes the data message accordingly.
The use of the precedence designators can be summarized as such:
• Immediate precedence is used to place data near the top of the queue and request the
Data Over Voice Interrupt feature.
• Priority precedence is used to place the data near the top of the queue without
invoking the Data Over Voice Interrupt feature.
• Routine precedence is used to place the data at the bottom of the queue.
Immediate precedence is used to automatically clear the channel of voice calls by using the Data
Over Voice Interrupt feature prior to beginning the data transmission. This capability departs from
the typical behavior of a radio system, which normally gives priority to voice calls over pending
data calls. The radio user whose transmission was interrupted receives a Talk Prohibit Tone until
the user releases the PTT.
For the Data Over Voice Interrupt feature to operate consistently, all radios using the channel
should be provisioned with the ability to be interrupted. If some radios are provisioned without the
ability to be interrupted (e.g., normally desirable for a supervisor’s radio), then those radios’
transmissions cannot be interrupted, and the data message will be placed near the top of the data
queue (behind any existing queues for Immediate precedence data messages). When Immediate
precedence is designated and a data (or control) transmission occupies the channel, the radio
must wait for the channel to become clear before initiating the data transmission.
Priority precedence is used to ensure that the data message is transmitted before any Routine
precedence data messages, and after any existing Immediate precedence data messages.
Priority precedence does not use the Data Over Voice Interrupt capability. When either Priority or
Routine precedence is designated, the radio must wait for the channel to become clear before
initiating the data transmission.
NOTE: The Data Precedence and Data Over Voice Interrupt features do not need to be configured
in the radio or repeater via the CPS because these features are always available.
For more information on the Data Precedence and Data Over Voice Interrupt features, please refer
to the MOTOTRBO Option Board ADK Development Guide on the MOTODEV Application
Developers website.
http://developer.motorola.com
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54 System Feature Overview
2.5 Scan
MOTOTRBO supports scanning of analog voice, digital voice, data, and digital signaling through a
repeater or directly from another radio. MOTOTRBO radios scan channels or groups, or both. In
Capacity Plus mode, it scans the groups only.
When scanning channels, the radio continuously searches a list of channels for activity of interest.
When activity of interest is found, the radio stops and switches to that channel. When finished, the
radio continues scanning the channels in the list.
The set of channels to be scanned (or scan members) are determined by a configured Scan List. A
radio can have multiple Scan Lists, and each channel in a radio can be associated with a different
Scan List. Scan Lists can contain only analog channels, only digital channels, or a mixture of both
analog and digital channels. Once scan is started, the radio scans through each scan member of
the associated Scan List for the selected channel.
The CPS allows a user to create, edit, or delete scan members in a Scan List, as well as associate
a Scan List to a channel. The user can start or stop scan, and also add or remove scan members
of a Scan List using the radio’s interface. Changes to the Scan List made by the radio are
persistent until the radio is turned off. Note that Scan and Roam are mutually exclusive on a
channel within CPS.
When the radio is scanning, and it detects a digital scan member in its Scan List, it looks for
transmissions targeted towards the group(s) associated with that channel. The radio also looks for
transmissions targeted towards itself (e.g. private calls or signaling commands). The radio can be
configured such that replies that occur within a specified duration is transmitted to the same group
and channel (this reply is called talkback). If the reply occurs outside of this duration, it is
considered a new transmission.
There are also options for where new voice transmissions (outside of the previously mentioned
duration) are transmitted while scanning. Voice can be configured to transmit on the selected
channel (the channel from which scan was started), another predetermined channel, or on the last
landed channel for voice (the last channel that scan “locked-on-to”). Data and digital signaling are
always transmitted on the selected channel. The last landed channel is not updated for data and
digital signaling.
Priority levels can also be configured for members of a Scan List. There are three levels of priority
within a scan list – Priority-1, Priority-2, and Non-Priority. The Priority-1 and Priority-2 channels are
scanned more often than the Non-Priority scan members. Priority scan is available with any mix of
analog, digital, talkaround or repeater channels.
The Scan List can be configured to have one Priority-1 member and one Priority-2 member; the
remaining are considered Non-Priority. When scanning, these priorities affect the order of
scanning. The following represents the scan order of Scan List: Priority-1, Priority-2, Non-Priority1, Priority-1, Priority-2, Non-Priority-2, Priority-1, Priority-2, Non-Priority-3, etc. However, the radio
may reorder Non-Priority scan members in order to optimize the efficiency of the scan.
In the CPS, there are two parameters associated with scan lists - Set/Clear Priority-1 and Set/
Clear Priority-2. These are used to mark a scan list member as Priority 1 and Priority 2; unmarked
list members are “non priority”.
While scanning, the radio can accept data (e.g., text message, location, telemetry, or terminal (PC)
data). However this is only applicable if the data is received on its selected (home) channel.
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NOTE: In MOTOTRBO radio’s with software versions R01.04.00 or later, various enhancements
were made to the scan engine to improve scanning performance. This has caused some
features, such as scanning for Group Text Messaging and Emergency Alarms, to no longer
be backward compatible with older software versions. All equipment must be upgraded for
these features to perform correctly.
2.5.1 Priority Sampling
When scanning, if some activity of interest is found, the radio stops and switches to that channel. If
the activity of interest is incoming data addressed to the scanning radio, an individual voice call, or
it is on a Priority-1 scan member, scanning completely stops for the duration of the call. But if the
activity is a voice group call on a Priority-2 or a Non-Priority scan member, the radio continues to
periodically scan higher priority scan members.
For example, if the radio is receiving voice on a Non-Priority scan member, then the Priority-1 and
Priority-2 scan members are scanned periodically. In this case, the order of scan will be: Priority-1,
Priority-2, Priority-1, Priority-2, etc. If the radio is receiving voice on a Priority-2 scan member, then
only the Priority-1 scan member is scanned periodically. If a transmission of interest is found on
the higher priority member, the radio switches to that member to monitor the transmission. If it is
not of interest, it returns to the previously monitored member. Priority Sampling does not occur
when transmitting.
Because the radio is currently receiving voice, leaving the current scan member to scan a higher
priority member will cause the radio to temporarily leave the current transmission. This causes an
audio hole in received audio that is being played through the radio’s speaker. Thus, the intervals
during which the radio samples the higher priority members, essentially, becomes the audio holes
that are introduced into the currently monitored voice. If there are two priority channels configured,
this time is how often a sample is taken of either one. Therefore, one particular channel is sampled
at a rate of double the priority sampling duration. A balance between how often an audio hole is
introduced and how often a channel is sampled needs to be achieved to ensure that transmissions
are not missed and to prevent introducing too many audio holes. This interval is CPS configurable
via the “Priority Sample Time” interval parameter. Since the radio only samples at the rate of the
Priority Sample Time, it is important to understand that if sampling for data, the Scan Preamble
must be set to double the Priority Sample Time.
The user experiences few to no audio holes if he is currently unmuted to a lower priority voice
while the priority member is in the other timeslot of the same repeater. In this situation, the radio
uses the embedded signaling in the repeater to monitor activity in the other timeslot. This should
be taken into consideration when deciding which identifiers are assigned to which channels and
slots.
Not all identifiers are uniquely identified in the embedded signaling because they are compressed
into smaller identifiers. If the system contains two or more identifiers that share the same
compressed identifier, the radio incurs additional audio holes to validate the actual uncompressed
identifier matches.
Duplicate compressed identifiers can be avoided if kept within a 256 ID range where the first ID of
the range is an integer multiple of 256. For example if group and individual identifiers are kept
between 0 and 255, or 256 and 511, or 512 and 767, etc., they will have unique compressed
identifiers and no audio hole will be experienced while priority sampling the other timeslot.
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56 System Feature Overview
Setting a busy channel as a priority channel can cause excessive audio holes in non-priority audio
as the radio checks each new transmission on the priority channel to determine if it is call of
interest. If the priority channel has many short transmissions that are not of interest, the radio will
be forced to incur at least one audio hole for each. Therefore, it is recommended, that if possible,
high priority transmissions should be isolated on channels that are not overly utilized by other
traffic.
2.5.2 Channel Marking
In addition to configuring the sampling interval for Priority Sampling, MOTOTRBO offers a way to
mitigate the duration of the audio hole itself with a feature called Channel Marking. Although
relatively short, it does take time to determine if a transmission is of interest on a particular scan
member. During this time, there is an audio hole in the scanned audio.
The Channel Marking feature introduces logic that assumes that if a transmission was recently
identified as not of interest, there is no need to fully review it at every scan interval. Additionally, if
the type of transmission is of the same type as the transmission identified as not of interest before,
there is a high likelihood it is the same transmission. Therefore, the radio only needs to identify the
type of transmission taking place, which is beneficial as identifying a transmission type takes much
less time than fully identifying if a transmission is not of interest. This assumption is made for a
pre-determined number of times, after which, the scan member is fully reviewed again. This
method changes the experienced audio holes from long audio holes every priority scan interval to
one long audio hole followed by numerous short audio holes, and then another long audio hole,
and so on.
This feature can greatly increase audio quality while a radio is in priority sampling mode. The
drawback to channel marking is the assumption that the target of a transmission has not changed.
The scanning radio will not know if the target has changed until the next full inspection. The
system should be configured in such a way using CPS parameters to achieve a balance which
delivers improved audio quality without sacrificing too much flexibility to consistently locate new
transmissions which otherwise would be of interest. It is recommended that Channel Marking is
set as Enabled in most scenarios.
However, if there is an analog signal on a digital priority channel, the radio will incur a medium size
audio hole on every sample even if channel marking is enabled. The radio spends this time
searching for synchronization that is not present. It is recommended that the priority traffic be
placed on a channel that has limited analog interference (i.e. shared use).
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2.5.3 Scan Considerations
The ability to scan multiple channels is an advantage when a user must be aware of activity on
numerous channels. MOTOTRBO offers the ability to scan a list of analog and digital channels
(frequency and slot) within the same scan list (often referred to as a Channel Scan List). This
feature is incredibly useful when planning to migrate from analog to digital, or when a user must
monitor multiple repeater frequencies and slots at the same time. When operating in digital,
MOTOTRBO also provides the ability to scan multiple groups on a channel (slot). This is often
referred to as a Group Scan.
A Group Scan is an optimized way to scan for multiple groups on the same channel (slot). The
radio monitors the channel from either the repeater or directly from another radio to determine
which group is currently transmitting. If the group transmitting is one specified in the Group Scan
List, the radio will stop and listen. The radio is allowed to talkback to the group for the duration of
the call hang time. This call hang time overrides the TX Contact Name setting of the channel.
Because only one call takes place on a channel (slot) at any given time, the scanning radio will not
miss a transmission of interest, regardless of the length of the group list. A Group Scan is
configured by creating a group list and adding groups already in the Contacts folder. This group list
can then be selected as the RX Group List of a particular Channel. The Group Scan does not have
the advanced features and configuration options of a channel scan. For example, once configured
via CPS, the Group Scan cannot be turned on or off and members cannot be added or removed.
Furthermore, the configurable scan options (Scan Hang time Timer, Talkback, etc.) do not control
the Group Scan. The Group Scan should be used in simple systems where no advanced scan
options are required. If advanced scan options and features are required, a Channel Scan should
be configured instead.
In Capacity Plus mode, MOTOTRBO radios only support Group Scan.
• All idle radios can perform a Group Scan at the start of a call. A call always starts on the
rest channel and all idle radios are on the rest channel.
• At the end of a call, the participating radios are informed about the ongoing calls,
allowing them to perform a Group Scan.
• When a radio powers on or when it comes into coverage, it searches the channels and
joins a call of interest (if any). If all the channels are busy, then a radio may not join an
ongoing call of interest.
A Channel Scan will scan a list of different channels within a system – analog or digital. A Channel
Scan is different from a Group Scan since the radio must change frequencies and sometimes even
modulations (analog to digital) in order to scan for activity. Unlike a Group Scan where only one
call occurs at any given time, when scanning different channels (analog or multiple digital slots),
there can be calls taking place on any or all of the channels. Because the radio cannot be
everywhere at once, there is a possibility that the radio will miss a transmission of interest.
Because of this, it is recommended that the number of channels in a Channel Scan list is kept to a
minimum. The larger the scan list, the more likely a user will miss, or join late, a transmission of
interest during busy times.
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58 System Feature Overview
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-
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- -
2.5.3.1 Scanning and Preamble
Since data and digital signaling messages are typically shorter in duration than voice
transmissions, it can be difficult for a scanning radio to detect such messages. This is especially
true as the number of scan list members increases because the amount of time between a
scanning radio’s repeated visits to a particular scan list member increases, making it less likely to
be on the channel at the exact moment that the data or digital signaling message begins. Another
factor is the amount of activity on each scan list member; basically, the more active each scan list
member is, the more likely that the radio is suspending its scan operations to receive on each of
those scan list members, further increasing the likelihood that the radio will not receive the data or
digital signaling on another scan list member. To improve the likelihood of receiving data and
digital signaling messages, the duration of these message types can be extended by preceding
the message with special preamble signaling. The amount of preamble signaling to use can be
configured into the initiating radio and the amount of preamble to use is dependent upon the
number of scan list members in the target radios’ scan list and whether priority scan is being used.
Since this added signaling increases the amount of airtime used for data and digital signaling
messages, there is a trade-off between increased channel loading and increased likelihood of
receiving data and digital signaling messages while scanning.
Suggested guidelines for the amount of preamble duration to use with scan lists not using priority
is provided in the following table. Scan preambles are not required for Capacity Plus.
Number of Analog Scan List Members
Number of Digital Scan List Members
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
0 480 480 480 720 720 720 960 960 960 960 1200 1200 12 00 1440 1440
1 720 720 720 960 960 960 960 1200 1200 1200 1440 14 40 1440 1440
2 480 720 720 96 0 960 960 960 1200 1200 12 00 1440 1440 1440 1680 1680
3 720 960 960 960 1200 1200 1200 1200 1440 1440 1440 1680 16 80 1680
4 960 960 1200 1200 1200 1200 1440 14 40 1440 1680 1680 1680 1680
5 960 1200 1200 1200 14 40 1440 1440 1680 1680 1680 1680 1920
6 1200 12 00 1440 1440 1440 1680 1680 1680 1680 1920 1920
7 1200 14 40 1440 1680 1680 1680 1680 1920 1920 1920
8 1440 16 80 1680 1680 1920 1920 1920 1920 2160
9 1680 16 80 1920 1920 1920 1920 2160 2160
10 1680 1920 1920 1920 2160 2160 2160
11 1920 1920 2160 2160 2160 2400
12 1920 2160 2160 2400 2400
13 2160 2400 2400 2400
14 2400 2400 2640
15 2400 2640
16 2640
The preamble duration should be increased when scan list members tend to carry lots of traffic or
long transmissions. If no radios in the system will use the scan feature, then the amount of
preamble may be set to zero.
March 2010 6880309T12
The preamble duration also should be increased when priority scan is being used. Since the
preamble signaling is used in conjunction with data and digital signaling messages, and directmode, and since digital-only scan lists support both priority scan and data and digital signaling
messages, the following table suggests guidelines for the amount of preamble duration to use with
direct-mode, digital-only scan lists using priority.
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System Feature Overview 59
Number of Priority Members
012
---
---
480 960 1200
720 1440 1920
960 1920 2640
960 1920 2640
1200 2400 3360
1200 2400 3360
1440 2880 4080
1680 3360 4800
1680 3360 4800
1920 3840 5520
1920 3840 5520
2160 4320 6240
2400 4800 6960
2400 4800 6960
2640 5280 7680
10
11
12
Number of Digital Scan List Members
13
14
15
16
0
1
2
3
4
5
6
7
8
9
If data and digital signaling is not carried on any of the non-priority channels and is only carried on
one of the priority channels (which must be the selected channel for data messages), then the
amount of scan preamble to use can be as specified in the first row of the Priority Scan table,
above, regardless of the number of non-priority scan list members.
2.5.3.2 Channel Scan and Last Landed Channel
A Channel Scan can be configured by selecting a group of already configured channels within a
radio using the CPS, and adding them to a Scan List. Each channel is then configured to use this
Scan List of channels. When scan is activated on a channel that contains a Channel Scan List, the
MOTOTRBO radio checks for activity on each of the channels on the list.
While scanning a digital channel for activity, all Groups specified in the channel’s RX Group List
will be monitored.However if the radio is configured with a Channel Scan that contains channels
that are configured with a RX Group List (a Group Scan), then only the Last Landed Channel is
remembered by the radio, not the Last Landed Channel and Group. This means that voice
transmissions are transmitted on the TX Call Member configured for the channel that was the Last
Landed Channel, not the Group in the Receive Group List of channel that was the Last Landed
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60 System Feature Overview
Channel. Note that if a transmission is made within the call hang time of the scanned transmission,
it will be targeted towards the landed channel and group. If it occurs after the call hang time has
expired, it will be targeted towards the TX Call Member.
When using the Last Landed Channel option, it is recommended for each group to have its own
configured channel. This way there is only one group associated with a channel, essentially
making the Last Landed Channel and the Last Landed Group the same.
2.5.3.3 Scan Members with Similar Receive Parameters
When adding members to a scan list, it is important to be conscious of the differences and
similarities between their receive parameters. A scan list that contains scan members with the
same receive parameters but different transmit parameters may result in misdirected reply
transmissions. This is best explained by first describing the simplest example of such a scenario.
F2
F2
F1
F1
Radio 1
Radio 2
Scanning
Radio
Channel 1
F1
F1
F3
F3
Channel 2
Figure 2-10 Misdirected Response while Scanning
In this example, a scan list contains two scan members, Channel 1 and Channel 2. Channel 1 is
an analog channel configured for carrier squelch with a receive frequency of F1 and a transmit
frequency of F2. Channel 2 is an analog channel configured for carrier squelch with a receive
frequency of F1, but with a transmit frequency of F3. A scan list such as this implies that there is a
repeater that is transmitting on F1 and receiving on F2, and another that is transmitting on F1 and
receiving on F3 (See Figure 2-10 “Misdirected Response while Scanning”). Since the radio only
listens and qualifies using the receive parameters while scanning, the scanning radio could
monitor a transmission from either repeater on either scan member. It does not know if it has
actually landed on the correct channel or not. It only knows that the receive parameters have been
qualified for the current channel being scanned. In other words, it does not know if the transmit
parameters of the channel it has landed on matches the receive parameters of the radio that is has
monitored. If the radio has landed on the wrong channel, when the radio user replies, the radio will
transmit on the wrong frequency. The result will be a misdirected reply about half the time. This
scenario can be avoided by making at least one of the receive parameters unique. In an analog
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System Feature Overview 61
system, this could be done with the use of PL or DPL. In a digital system, this can be done by
using a unique color code or unique group per channel. This will allow the scanning radio to only
“land” on the channel where all receive parameters match and therefore properly direct the user’s
reply.
F2
F2
F1
F1
Radio 1
Channel 1
Scanning
Radio
F1
Radio 2
Figure 2-11 Misdirected Response while Scanning
Similar problems can occur if one scan member has fewer qualifiers than the others. Taking the
example in Figure 2-10 “Misdirected Response while Scanning” again, Channel 1 is still an analog
channel configured for carrier squelch with a receive frequency of F1 and a transmit frequency of
F2. However, Channel 2 is now a digital channel configured for Color Code 1 and Group 10 with a
receive frequency of F1 and a transmit frequency of F3. The receive parameters in this example
are different, but Channel 1 has few qualifiers. Channel 1 is configured to land on any transmission
that breaks squelch. This means that any transmission that occurs on Channel 2 will be heard on
Channel 1 as an analog signal. This scan list will not only result in misdirected replies, but it also
results in a digital transmission being played out the speaker as analog. The net result is
undesirable sounds presented through the user’s speaker. This type of configuration should be
avoided at all times. This could be avoided by utilizing a PL or DPL on the analog channel instead
of only carrier squelch.
Another similar problem occurs when the unique receive parameters between scan members are
missing or cannot be determined. One scenario where this occurs is while scanning two slots of a
repeater and a transmission is received directly from a subscriber on the same frequency. A radio
in repeater mode can receive a transmission directly from a radio. However, in direct mode, slot
numbering is not utilized. Therefore, if a radio is scanning two scan members with the same
qualifiers with the exception of the unique slot number, when it receives a transmission without a
slot number, either scan member will monitor it and “land”. When the user replies, the transmission
will be returned through the repeater on whichever slot assigned to the scan member it was
monitored on. Depending on the configuration of the direct mode radio and its proximity to the
repeater, the transmission may or may not be monitored. This can be managed by having different
groups configured for each slot. This ensures that each slot has unique identifiers besides just the
slot number. However, this does not help if the subscriber in direct mode is out of range of the
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62 System Feature Overview
repeater. This is why it is not good practice to transmit in direct mode in the RF range of the
repeater.
Generally, these scenarios can be avoided if scan lists are created with scan members that have
unique receive parameters.
2.5.4 Transmit Interrupt and Scan
Some of the Transmit Interrupt features and scan can be used together. However, there are a few
interactions that need to be taken into consideration, as discussed in the following paragraphs.
Firstly, since scan is not permitted when the radio is in an emergency mode of operation,
Emergency Voice Interrupt and scan do not have any direct interactions to consider because these
two features are mutually exclusive. However, if a radio is in scan mode when the radio user
initiates an emergency condition, the radio first exits the scan mode of operation, and then enters
the emergency mode of operation (optionally following emergency revert procedures). At this
point, Emergency Voice Interrupt could be invoked, if the feature has been configured in
accordance with the Emergency Voice Interrupt operation as described previously.
The second interaction to consider occurs when the radio is provisioned for both the Scan Priority
Sampling and a Transmit Interrupt feature. Priority Sampling is temporarily suspended when a
Transmit Interrupt request is pending. This is necessary to ensure that the radio user’s transmit
request takes priority over the radio’s receive activities.
Thirdly, the radio can be configured with the scan feature such that replies occurring within a
specified duration are transmitted to the same group and channel (this reply is called talkback). A
reply that occurs outside of this duration is considered a new transmission.
If the radio is provisioned for Transmit Interrupt and talkback, then Transmit Interrupt is applied to
the same group and channel, when the radio user invokes a Transmit Interrupt feature while
receiving. If the designated transmit channel is busy and the radio is not a member of the ongoing
call, then the Voice Interrupt request is simply denied.
Recall the options for new voice transmissions – outside of the previously mentioned duration –
are transmitted while scanning; include the selected channel (the channel from which scan was
started), another predetermined channel, or on the last landed channel for voice. Data and digital
signaling are always transmitted on the selected channel. The last landed channel is not updated
for data and digital signaling. In the event that the channel selected for a new transmission is busy,
a Transmit Interrupt feature may be invoked on that channel if so provisioned on that channel.
However, the radio must additionally be a member of the call in progress for Voice Interrupt to be
invoked.
Finally, a radio’s interruptible voice transmission periodically stops transmitting momentarily, and
“listens” to the channel to determine whether it is being requested to stop its transmission. When a
radio is scanning channels and testing the channel for presence of a carrier while another
transmitting radio is listening to the channel for Transmit Interrupt signaling, the scanning radio
may conclude that the channel has no activity and moves on to the next channel in the scan list.
However, this occurrence should happen only occasionally. It is most likely that the next time the
scanning radio visits the channel, it will not occur at the moment that the transmitting radio has
suspended its transmission. The net result is that the time taken to detect channel activity for an
interruptible voice transmission may increase slightly, versus uninterruptible voice transmissions.
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System Feature Overview 63
Since the repeater is transmitting continuously even during interruptible voice calls, this is only a
concern when scanning channels that may contain interruptible voice Direct Mode transmissions.
2.6 Site Roaming
MOTOTRBO supports the ability to automatically roam between sites of an IP Site Connect
system.
The portable and mobile can be configured with a roam list that contains a list of channels, each of
which is one site (one repeater) of an IP Site Connect system (wide area system). The radio
searches through the list of sites and selects the one with the strongest signal, and identifies this
site as its current home site. The radio remains on this home site until the signal strength has
dropped below a programmable threshold or when it has lost communications with the home site,
at which time it attempts to find a better home site. If a better home site is not found, it remains on
the previous home site and continues searching. Note that roaming occurs while the user is not in
a call. Roaming is not supported while the user is in a call.
Although site roaming functions automatically, the radio user can be provided the ability to control
when and where the radio roams. The radio user can lock on to a particular site, or remain
unlocked and allow the radio to choose the appropriate site. To manually change sites, the user
can either change their radio dial position to the desired channel or site, or they can initiate the
Manual Site Roam feature and have the radio find the next available site. When the user changes
radio dial positions, the radio always begins on the selected channel. The Site Lock On/Off and
Manual Site Roam controls can be configured to be accessible through a button or the menu.
The radio user is provided indications via the LED on when the radio is roaming. They are also
provided an indication on which site the radio is currently on when the user enables Site Lock via
button press.
The radio has two methods in which it accomplishes the act of roaming; a passive method and an
active method.
2.6.1 Passive Site Searching
The Passive Site Search method has the radio searching through a list of sites and selecting the
one with the strongest signal. This method is utilized whenever the site is unlocked. It relies on
repeater transmissions in order for the subscriber to determine which site has the strongest signal
strength. Since it is expected that the radio will encounter other activity while performing the
Passive Site Search, it qualifies the signal using the sites’ programmed color code prior to
selecting it as the new home. In addition, it sorts the sites in the roam list according to their signal
strength in order to optimize follow up roams. Sites that have been detected in previous roam
attempts and are assumed to be near by are searched before those that have not been detected
before. Also, while roaming, the radio inspects the current home site in between other sites in
order to minimize the time away. This strategy provides priority to the last home site and minimizes
missing any transmissions while performing the roam attempt.
While passively roaming, the radio temporarily leaves the current home channel and inspects
other sites to decide if a better site is available. It is important to note that since the radio is
temporarily away from the home channel, it is possible to miss the beginning of a transmission
(late entry). Because of this, it is not advisable or required to perform passive roaming all the time.
Therefore, the radio should only passively search for a better site when the current home site is no
longer desirable. If the radio is within good coverage of a site, there is no need to search for a
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64 System Feature Overview
better site. In other words, the radio should only passively roam when the radio has moved far
enough away from the site that its signal strength has degraded below an acceptable value or
when its signal is no longer present. The signal strength threshold to initiate the Passive Site
Search (Roaming RSSI Threshold) is configurable via the CPS. See “Configuring the Roaming
RSSI Threshold” on page 68 for suggestions on setting the Roaming RSSI Threshold for various
site configurations and scenarios.
Initiating Passive Site Search and selecting sites based on signal strength works well when the
repeater is transmitting, but the MOTOTRBO repeater does perform in a shared-use environment
and is required to de-key when not in use. If there is no activity on a system, the Passive Site
Search cannot detect any repeaters and therefore is unable to determine at which site the radio
should be on. Therefore, the repeater can be configured to transmit a beacon, which is a periodic
short transmission when there is no interference, when not transmitting. Both the beacon duration
and interval are programmable.
During times of no activity, the radio utilizes the signal strength of the beacon to determine when it
should roam and which site it should roam to. If the radio does not receive a beacon in the
expected duration, it assumes it is out of range of the repeater or that the repeater has failed and
roams to another site. The duration of the beacon is a function of the number of sites in the IP Site
Connect system and therefore in the roam list. The interval of the beacon is a function of the
shared use rules of the channel and how quickly a radio is required to roam when there is no
activity. See “Setting Beacon Duration and Beacon Interval” on page 73 for suggestions on setting
the beacon duration and interval for various site configurations and scenarios.
The radio does not perform Passive Site Search while:
• transmitting,
• receiving a call of interest,
• in emergency,
• in good RF coverage,
• in talkaround (direct) mode,
• radio disabled,
• received call alert,
• monitor mode,
• microphone is off hook,
• while in active menu, or
• while on a channel that has a scan list
2.6.2 Active Site Searching
The Active Site Search method consists of the radio sending a repeater wake-up message to each
repeater in its sorted roam list until it finds an active site. This method is utilized when the user or
radio initiates a transmission and the home site repeater cannot be awoken, or when the user
initiates a Manual Site Roam.
In most cases, the Passive Site Search determines and selects the correct site if the radio is in the
unlocked state. If the repeater’s beacon interval is set too long then it may be possible that the
radio has roamed into a new site and has yet to receive a beacon. Note that the beacon interval is
usually in the range of minutes and it typically takes more than a minute for a radio user to move
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out of range of one site and into the range of another. Until a new site is found, the radio considers
the previous site as the home site.
If the user presses the PTT or a data transmission is requested at this time, the radio will first
attempt to wake-up the home repeater. If the repeater does not wake up, the radio repeats this
process for each roam list member. If the repeater does wake up, the radio synchronizes itself with
the repeater, completes the transmission and make the new site the home site. If the end of the
roam list is reached and a site is not found, the user receives a failure indication.
This entire process of discovering and synchronizing with an active repeater increases the voice
access time of the transmission (time from PTT to Tal k Pe rm it To n e ) . H o w e ver, this increase only
occurs for one transmission since the next transmission proceeds regularly on the new site.
NOTE: Wake-up messages are always sent politely. This means that if the radio detects an
interfering signal, the radio does not transmit a wakeup message on that roam list member.
Instead, it continues performing an Active Site Search on the next roam list member.
If the user requests a Manual Site Roam, be it through a button press or menu item, the radio
actively searches for the next available site using the process described above. The Manual Site
Roam does not necessarily find the best site, but rather allows the user to move to the next site
that is in range and transmitting. If no site is found, a negative indication is provided to the user. If
in direct mode, a successful site search changes the new channel found to repeater mode. An
unsuccessful site search remains in direct mode.
NOTE: Generally, the radio does not perform any Passive Site Search during an emergency. No
automatic roaming is performed when the radio is reverted during an emergency.
However, when configured to a non-revert emergency channel and with Active Site Search
enabled, the radio will perform Active Site Search automatically whenever the RSSI of the
repeater drops below the programmed threshold or if it no longer detects repeater
beacons. Note that Manual Site Roam is supported while in an emergency. See
“Emergency Revert, GPS Revert, and Roaming Interactions” on page 75 for more details.
It is important to note that Active Site Search causes wake-up messages to be transmitted on each
roam list member’s frequencies until a site is found. This may not be agreeable in some areas
where frequency overlap and sharing is common. In order to minimize the number of unwanted
transmissions, the radio shall only transmit one polite wake-up message. If sending frequent GPS
location updates while out of range, the radio shall limit the Active Site Search to only occur once
every 30 seconds.
If this is still not acceptable in the area of operation, the radios should have automatic Active Site
Search disabled, the Manual Site Roam button removed, and the beacon interval should be
configured as short as possible. This ensures that the Passive Site Search finds new sites quickly
and the user has no method to initiate an Active Site Search. Note that if Active Site Search is
disabled, there will be no roaming while in an emergency.
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2.6.3 Roaming Considerations
2.6.3.1 Configuring a Roam List
When configuring a Roam List it is important to keep in mind that a system can contain more than
one IP Site Connect system, or also known here as a wide area system. A wide area system is
made up of one or two wide area channels. Each wide area channel is an individual voice path, in
other words, the users on the same wide area channel monitors each other on any site.
Figure 2-12 shows a system with 2 sites, 2 wide area systems, each with 2 wide area channels.
Wide Area System 1, Channel 1 (WAS1 CH1) represents a wide area channel in wide area system
1.
Site 1
WAS1 CH1
WAS1 CH2
WAS2 CH1
WAS2 CH2
Network
Site 2
WAS1 CH1
WAS1 CH2
WAS2 CH1
WAS2 CH2
Figure 2-12 Two Wide-Area Systems, Each with Two Wide-Area Channels
Each wide area channel should have its own roam list. The roam list should contain one logical
channel from each site that corresponds to the wide area channel. A logical channel is defined as
the frequency pair, color code, timeslot combination. If there are multiple personalities (CPS
Channels) that reference the same logical channel, only one should be added to the wide area
channel roam list. Only wide area channels should be added to the roam list.
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The table below shows an example of the two site configuration in CPS. The colors match those of
Figure 2-12 to help clarify.
Zone/
Folder
(Alias)
Zone 1
(Site 1)
Zone 2
(Site 2)
The roam lists are configured as shown below:
Personality
(CPS Channel)
# - Alias
1 – SITE 1 TGA 1 1 1 TGA 1 – WAS1 CH1
2 – SITE 1 TGB 1 1 2 TGB 2 – WAS1 CH2
3 – SITE 1 TGC 2 1 1 TGC 3 – WAS2 CH1
4 – SITE 1 TGD 2 1 2 TGD 4 – WAS2 CH2
5 – SITE 2 TGA 3 2 1 TGA 1 – WAS1 CH1
6 – SITE 2 TGB 3 2 2 TGB 2 – WAS1 CH2
7 – SITE 2 TGC 4 2 1 TGC 3 – WAS2 CH1
8 – SITE 2 TGD 4 2 2 TGD 4 – WAS2 CH2
Roam List
# - Alias
1 – WAS1 CH1
Freq Pair
Logical Channel
Color
Code
Personality (CPS Channel)
Time Slot
# - Alias
1 – SITE 1 TGA
5 – SITE 2 TGA
Group
Roam List
# - Alias
2 – WAS1 CH2
3 – WAS2 CH1
4 – WAS2 CH2
As can be seen there are 4 roam lists required for the 4 wide area channels. Each roam list
contains only one personality that references the desired logical channel at each site. Although not
necessary, personalities that correspond to a site can be placed together in their own zone (or
folder). This will help further remove the concept of site from the radio user and allow the site
roaming feature to choose the appropriate site. If they must manually choose a site, they can
change zones. Using the actual name of the site as the zone alias will help clarify this to the end
user, but it is not required. Since the same group is mapped to the same dial position in each zone,
the user will have the same group selected as they change through the sites (zones). In this
example the personalities are aliased with the group names, but other aliases that define Site,
Channel, or Group name can be used. If there are more than one group per wide area channel, a
roam list can be created for each group to utilize.
2 – SITE 1 TGB
6 – SITE 2 TGB
3 – SITE 1 TGC
7 – SITE 2 TGC
4 – SITE 1 TGD
8 – SITE 2 TGD
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It is important to understand that when the radio determines a new home site to be one of the roam
list members, it will only utilize the logical channel attributes of the roam list member. The
remaining attributes will be used from the selected personality.
The following logical channel attributes of the home site are utilized:
• Transmit Frequency and Transmit Reference Frequency,
• Receive Frequency and Receive Reference Frequency,
• Color Code,
• Time Slot,
• Talkaround Setting,
• GPS Revert Channel
• Emergency System (Including Emergency Revert Channel)
Take specific note of the GPS Revert and Emergency Revert channels. Because physical
channels will be different per site, the revert channels must change when the radio roams to
another site. It is recommended that emergency settings (other than revert channel) should be the
same for all personalities within a roam list. Otherwise the radio may perform an emergency
differently as it moves from one site to another.
The remaining personality attributes (Transmit and Receive Group List, Channel Access, etc.) will
be used from the currently selected channel regardless of which site the radio is currently roamed
to. It is good practice to make these parameters identical for personalities within a roam list so that
the radio acts the same regardless if it roams to the personality or if the user selects the
personality.
2.6.3.2 Scan or Roam
When selecting a roam list for a personality to utilize, one will notice that a personality cannot
contain a roam list and a scan list. MOTOTRBO does not currently support the ability to roam
between sites and then scan channels at a particular site. Therefore while on a particular
personality, a user has the ability to roam or scan, not both.
2.6.3.3 Configuring the Roaming RSSI Threshold
The Roaming RSSI Threshold is a CPS configurable parameter that controls the signal strength a
subscriber needs to reach before searching for another site. If the RSSI measurement of the
currently determined home site is above the specified Roaming RSSI Threshold, then the radio will
remain on that site and not roam. Once the RSSI measurement drops below the threshold it will
begin a Passive Site Search process to find a site with higher signal strength. This parameter
essentially controls the distance away from a site a subscriber will begin looking for another site. In
real life environments RF coverage is seldom a perfect circle, but to simplify this explanation,
coverage will be abstracted as a circle.
It is important to note that while passively roaming the radio temporarily leaves the current home
site to determine if a stronger site is available. Since the radio is temporarily away from the home
channel, it is possible to miss the beginning of a transmission (i.e. enter the call late). Because of
this, it is not advisable to perform passive roaming all the time.
The setting of the Roaming RSSI Threshold is a balance between when a radio will leave one site
and look for the next versus how often the radio will perform roam and therefore increase the
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chances of late entry to voice calls. If the Roaming RSSI Threshold is too low, the radio will remain
on a low signal strength home site even though there might be a stronger site available. If the
Roaming RSSI Threshold is too high, the radio will be roaming in full coverage of a repeater and
causing late entry when not required. Figure 2-13 shows the impact of the Roaming RSSI
Threshold value in relationship to the good coverage line (dotted) which most system coverage is
designed to meet. Note that the Roaming RSSI Threshold is a negative number therefore a high
value is -80dBm and a low value is -120dBm. The colored area is where the radio would roam.
Good Coverage
Low Roaming RSSI Threshold
High Roaming RSSI Threshold
Not Roaming
Roaming
Figure 2-13 Roaming Triggered by Roaming RSSI Threshold Value
The default value of the Roaming RSSI Threshold is -108dBm. It can be programmed for anything
between -80dBm and -120 dBm. A value of -108dBm is approximately 80% of the good coverage.
Therefore roaming will occur in the outer 20% of coverage. The default value is acceptable for
most configurations but may not be optimal in a some particular configurations. Before setting the
Roaming RSSI Threshold, one must consider the customer’s site configuration.
Consider the following four basic site configurations:
1.Dense Overlapping Coverage (Urban) – This type of coverage consists of dense sites
with generous overlap. This coverage type is often found in large cities or highly populated
areas. Overlapping sites utilize different frequencies. Non-overlapping sites may share
frequencies, but those that do share frequencies need to have different color codes if they
need to be distinguished while roaming. This type of coverage is highly likely to
encountered shared use on one or all of its sites. A radio user may be within coverage of
three to four sites at a time. The time it takes a radio user to move from the coverage of
one site to another is in the range of 10 minutes.
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2.Isolated No Overlapping Coverage (Rural) – This type of coverage consists of isolated
sites with little to no overlap. This coverage type is often used for isolated sites in rural
areas, although could be used to cover a single part of a small city. Non-overlapping sites
may share frequencies, but those that do share frequencies need to have different color
codes if they need to be distinguished while roaming. This type of coverage is less likely to
encountered shared use although possible. A radio user will only be within coverage of
one site at any time. The time it takes a radio user to move from the coverage of one site
to another is in the range of multiple hours.
3.Corridor Coverage – This type of coverage consists of in-series slightly overlapping sites.
This coverage type is often used for covering highways, train tracks, shore lines, or rivers.
Frequency re-use is common in this configuration since one site only overlaps with its two
adjacent sites. Non-overlapping sites may share frequencies, but those that do share
frequencies need to have different color codes if they need to be distinguished while
roaming. A radio will only be within coverage of one to two sites at a time. The time it takes
a radio user to move from the coverage of one site to another is in the range of an hour.
4.Multi-Floor Coverage – This type of coverage consists of dense extremely close sites
with short range coverage and generous overlap. This coverage type is often used for
covering tall buildings, or deep tunnels. Frequency re-use is not common due to the small
coverage footprint usually implemented with in-building radiax antenna systems. This
coverage type also often encounters quick signal strength drop offs due to the nature of in
building coverage. Non-overlapping sites may share frequencies, but those that do share
frequencies need to have different color codes if they need to be distinguished while
roaming. A radio will only be within coverage of one to two sites at a time. The time it takes
a radio user to move from the coverage of one site to another is in the range of one
minute.
Reference the following diagrams.
TX = F1
RX = F2
CC = 1
TX = F5
RX = F6
CC = 4
TX = F3
RX = F4
CC = 2
TX = F1
RX = F2
CC = 3
Figure 2-14 Dense Overlapping Coverage (Urban)
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TX = F1
RX = F2
CC = 1
TX = F5
RX = F6
CC = 4
Figure 2-15 Isolated No Overlapping Coverage (Rural)
TX = F1
RX = F2
CC = 1
TX = F3
RX = F4
CC = 2
TX = F1
RX = F2
CC = 3
TX = F3
RX = F4
CC = 2
TX = F1
RX = F2
CC = 3
Figure 2-16 Corridor Coverage
TX = F5
RX = F6
CC = 4
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72 System Feature Overview
TX = F1
RX = F2
CC = 1
TX = F3
RX = F4
CC = 1
TX = F5
RX = F6
CC = 1
TX = F7
RX = F8
CC = 1
Figure 2-17 Multi-Floor Coverage
The site configuration should be taken under consideration when the Roaming RSSI Threshold is
set. For example if the customer has a “Isolated No Overlapping Coverage” the threshold can be
set to its lowest value of -120dBm. Because there is no overlap, there is no reason for the radio to
start roaming until well outside of the coverage range of the repeater. For extremely close sites
with large overlaps and quick signal drop off like the “Multi-Floor Coverage”, it might be better to
set to it to a higher value so that the radios search for stronger sites closer to the repeater. The
following table is the suggested setting for each basic site configuration. Many radio systems will
have a combination of site configurations so the system designer will need to take all
configurations into consideration and choose an appropriate value.
Site Configuration
Recommended
Roaming RSSI Threshold
% of Outer Range
Radio Will Roam
Isolated No Overlapping Coverage (Rural) –120 dBm Out of Range
Corridor Coverage –110 dBm 10%
Dense Overlapping Coverage (Urban) –108 dBm 20%
Multi-Floor Coverage –102 dBm 50%
It is important to note that the preceding Roaming RSSI Thresholds assume the outbound and
inbound RF coverage of the system is balanced. In other words, when a radio is within good
outbound coverage of the repeater the radio’s inbound transmission can reach the repeater. Since
the roaming algorithm uses the outbound transmission to determine when to roam, having an
unbalanced system can cause radios not to roam even though they can no longer reach the
repeater. This can lead to radio transmissions that do not reach the repeater and are therefore not
repeated.
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One method to rectify this problem is to lower the output power of the repeater. This decreases the
outbound coverage area, but ensures that if a subscriber can hear the repeater well, it can
respond successfully. If lowering the output power is not desirable, the Roaming RSSI Threshold
needs to be raised higher (less negative) than the recommended values. This forces the radios to
roam to another site within very good RF coverage of another. This value may be different for
portables and mobiles since they have different output power and therefore different inbound
coverage. Portables may need a higher (less negative) Roaming RSSI Threshold than mobiles.
Also note that there is one Roaming RSSI Threshold per roam list. This means that if one site has
an inbound outbound imbalance and another does not, it may be difficult to find the correct
Roaming RSSI Threshold to exactly accommodate both sites. In other words if you set the
threshold to roam correctly on the imbalanced site, it may end up roaming too early on a balanced
site.
2.6.3.4 Setting Beacon Duration and Beacon Interval
If there is no activity on a system, the repeaters will hibernate and the radio’s Passive Site Search
are not able to determine the signal strength, and therefore, which site is best since repeaters are
not transmitting. Because of this, the repeater can be configured to transmit a beacon when not
active and there is no other interfering signal. During times of no activity, the subscriber utilizes the
signal strength of the beacon to determine when it should roam and which site it should roam to. If
the subscriber does not receive a beacon in the expected duration, it assumes it is out of range of
the repeater (or the repeater has failed) and attempts to roam to another site.
Both the beacon duration and the interval are programmable via CPS. The beacon duration is only
configured in the repeater, but the beacon interval is programmed in both the repeater and the
radio.
The duration and interval of the beacon is a function of the Over-the-Air shared use rules in the
customer’s region. The beacon duration is dependant on the number of sites in the IP Site
Connect system and therefore in the roam list. The beacon interval is dependant on how quickly
the radio is expected to roam to and from a site when there is no activity. The minimal duration and
interval need to be met while keeping within the shared use guidelines of the region.
The ratio of the beacon duration and beacon interval equate to how often the repeaters transmit
while there is no inbound radio activity, i.e. the beacon transmit ratio. This ratio is not directly
programmed into the system, but is rather a guideline for setting the Beacon Duration and Interval.
If on a shared use frequency the beacon transmit ratio should be kept low. The target ratio is
between 5% and 10%. In other words, if there is a need to increase the beacon duration, the
beacon interval must also increase in order to keep the correct ratio.
If the beacon duration is configured too short it can be difficult for a roaming radio to detect it. This
is especially true as the number of sites increases. As the amount of time between a roaming
radio’s repeated roam attempts to a particular site increases, it is less likely to be inspecting the
site at the exact moment that the beacon is transmitted. Recall that the home site is sampled in
between other sites, which increases the overall cycle time. A user is typically within the coverage
of no more than 4 sites at any given time, therefore even with a large roam list, most of the sites
have no activity and can be inspected very quickly. If numerous sites have shared-use frequencies
(i.e. interference) the radio takes longer to get through its roam list and this increases the time
between inspections of one particular site. Note that because the roam list is sorted by signal
strength, the nearer sites are inspected first. Alternatively, if a user is transitioning to a site that
they have not visited lately, the first roam may take slightly longer, but once it is has been detected
this site moves to the front of the roam list. To improve the likelihood of receiving the beacon, the
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beacon duration should be increased. It is safer to have a beacon duration longer than shorter, but
keep in mind that if the duration is increased, the beacon interval must be increased to meet the
beacon transmit ratio.
The beacon interval controls how quickly a radio can roam to a site and how quickly it roams away
from a site when there is no activity. When roaming with no system activity, a radio needs to see a
beacon in order to roam to a new site. If the repeater beacon is sent out every one minute, the
radio may be one minute deep into the site before it sees the site and roams to it. Similarly, when
roaming with no system activity, a radio may be one minute outside of the site before it attempts to
roam. The impact of this value often changes based on how quickly the users are traveling. For
example a car driving 60 m.p.h. can cover a mile a minute and therefore will be one mile into or out
of a site before roaming. This could be acceptable for site configurations such as the “Isolated No
Overlapping Coverage” or the “Corridor Coverage”, but the “Dense Overlapping Coverage”
coverage type may require a quicker beacon since it will both trigger the leaving and entering of
sites. Note again that if the user initiates a transmission before the passive roam finds the beacon,
the radio will attempt to wake-up the site repeater.
A one minute beacon interval may not be an issue for users on foot unless the sites are very close
like in the “Multi-Floor Coverage” example. In this case a user in an elevator can move between
sites at a very high rate. A one minute interval may cover the entire duration of an elevator ride
from the first floor to the top. Here, it is recommended to keep the beacon interval in the range of
20 seconds. Note that a beacon transmit ratio of a 5% may not be achievable for systems with a
high number of repeaters. In this case the designer may either decide to abandon the target
beacon transmit ratio since in-building coverage usually does not propagate very far or have
neighbors to interfere with, or lower the beacon duration to only cover the max number of
overlapping sites a radio may ever see.
The table below is the recommended beacon duration and beacon interval (8% beacon transmit
ratio) for a varying number of sites. The default value is a 4.32 second Beacon Duration with a 60
second Beacon Interval.
Number of Sites in
Wide Area System
Beacon Duration
(sec.)
Beacon Interval
(sec.)
20.7210
31.9230
43.1240
54.32*60*
65.5270
76.7290
87.92100
99.12120
10 10.32 130
11 11.52 150
12 12.72 160
13 13.92 180
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Number of Sites in
Wide Area System
14 15.12 190
15 16.32 210
If shared use is not a problem in the customer’s region, the beacon transmit ratio become less
important and it may be desirable to increase the beacon duration and decrease the beacon
interval past what is identified here. If the automatic Active Site Search feature is going to be
disabled, it is advisable to lower the beacon interval as much as possible since radios will rely only
on it to find the appropriate site.
Beacon Duration
(sec.)
Beacon Interval
(sec.)
* Default Values
2.6.3.5 Emergency Revert, GPS Revert, and Roaming Interactions
Emergency Revert and GPS Revert are specific to the current home site. This is important since
the revert channel of one site will most likely not be the revert channel of another site. Although it
is possible to revert while roaming, roaming while reverted is limited.
While in emergency and configured as non-revert the radio will not perform Passive Site Search. If
Active Site Search is enabled, the radio performs an automatic Active Site Search when the RSSI
of the repeater drops below the programmed threshold or if it no longer monitors the repeater
beacons (normal triggers for passive roam). This is considered as a more aggressive method to
site search as compared to passively searching. The radio also supports the ability to trigger an
automatic Active Site Search on transmit request by the user or automatically by the radio (GPS).
Standard Manual Site Roam is also supported. Active Site Search can be enabled or disabled via
the CPS.
While reverted due to emergency, no automatic roaming occurs. This is primarily due to the fact
that the emergency revert channels may not be on the same logical channel, and the emergency
handlers may not be the same. It is not desirable for a user to automatically leave one emergency
handler and switch to another without notification.
A radio will perform an Active Site Search (using the selected personality’s roam list) when the
emergency is first initiated if the revert channel is not available. Once on the revert channel, only
Manual Site Roam is available. In other words, if a user enters emergency, and then roams out of
range of the revert channel, the radio does not automatically roam even if the user presses the
PTT. When a Manual Site Roam is initiated while reverted, the radio performs an Active Site
Search using the selected personality’s roam list.
When a new site is found due to a roam while in emergency, the emergency process restarts on
the new site (similar to manually changing the dial position) if the new home is provisioned for
revert. If the new home is not provisioned as revert, the emergency process does not restart since
the radio never left the wide area channel. It is assumed that the original target of the emergency is
still monitoring since the source never left the wide area channel. The radio also assumes that
emergency handling configuration (outside of revert) is the same across the wide area channel.
The radio reverts if the new home site is provisioned as such. If a new site is not found, the radio
returns and remains on the original site or the site revert channel, if provisioned. Per normal revert
rules, upon clearing the emergency the radio would return to the home site. If the radio roams to a
site that has Emergency Disabled (or no Emergency System) then radio remains in emergency but
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does not process the emergency sequence. The user can then attempt another Manual Site Roam
to find a site that does have emergency.
Note that in most cases, the passive search while not in emergency should get the radio on the
correct site and therefore when it emergency reverts, it should still be at the same site. If in Silent
Emergency mode, no ergonomics associated with Manual Site Roam are displayed.
While GPS reverted, no automatic roaming is supported. If the GPS revert channel is out of range,
the data message is dropped. On return to the home channel after a failed GPS revert, the radio
will initiate an Active Site Search using the selected personality’s roam list. This will make sure that
an available site is found prior to the next GPS revert attempt.
While in emergency (initiator, not receiver) and GPS revert occurs, no automatic roaming is
supported while reverted. If GPS revert channel is out of range, the data message will be dropped.
On return to an emergency revert channel, after a failed GPS revert, the radio will NOT initiate an
Active Site Search since this is not supported while in emergency.
See “Emergency Revert and GPS Revert Considerations” on page 252 for further details on how
Emergency Revert and GPS Revert operate together.
In summary:
Feature
Tactical Emergency
(Non-Revert)
Emergency Revert Not Available
GPS Revert
Passive Site
Search
Not Available Available Available Available
Not Available
while Reverted
Automatic Active Site
Search on TX Request
Only Available on
Emergency Initiation
Performed After Dropping
the Data Message
2.6.3.6 Performance while Roaming
It is important to note that roaming (not just enabled, but in the act of searching) may cause some
minor degradations in performance. Therefore, it is important that the Roaming RSSI Threshold
and the radio’s Site Lock be set appropriately when not mobile. These degradations are similar to
what a scanning radio would experience. Degradation may be experienced in the following areas:
• Late Entry to Voice Transmissions (Voice Truncation)
• Longer Preambles required for Control Messages and Data
• Increased setup time for Confirmed Private Calls
• Group Call Time to Talk Permit may increase if Site Search Required
Automatic Active Site
Search on Loss of Site
Not Available Available
Not Available Available
Manual
Site Roam
While roaming the radio temporarily leaves the current home channel and inspects other sites to
decide if a better site is available (similar to scan). This means that radio may not be present on
the home site when a call starts. The home site is inspected between every other site to minimize
the time away. This is similar to the scan ordering of a priority scan member.
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One issue that arises from this situation is that if a group call or unconfirmed individual call starts
while the target is inspecting another site, the may be a short delay before joining the call. This will
equate to voice truncation for the target radio.
Another issue faced will be the need for longer preambles in order for command and control
messages, and data to be received by a radio that is currently roaming. Without an extended
preamble, roaming radios will miss the message.
The need for preambles also affects the setup time for confirmed private calls. Confirmed private
calls utilize command and control messaging to setup the call. In addition, the first setup attempt
does not utilize any preambles. This increases the setup time between radios that are not roaming.
This means that the first setup attempt of a private call is not successful if the target radio is
roaming. The radio then attempts a second time with a preamble. This second attempt will more
likely be successful and the private call will continue.
If the current home site cannot be awoken, the radio attempts to locate another site using an
automatic Active Site Search. As the radio attempts to wake-up other sites, the user must wait.
This increase in time will be recognized as an increase in the time from PTT to receiving the Talk
Permit Tone. This is not expected to occur often if the beacon interval is set appropriately.
It is expected that the value that the roaming feature adds is worth these performance
degradations. The Beacon Interval and the Roaming RSSI Threshold should be set appropriately
to minimize the amount of time a radio is searching for a site.
2.7 Voice and Data Privacy
Over a digital channel, MOTOTRBO supports a way to keep communication (both voice and data)
private. Privacy protects the information, where “protection” means that the MOTOTRBO resists
reading of data payload or listening of voice by anybody other than the intended receivers.
MOTOTRBO does not provide any mechanism to authenticate the radios or radio users and it
does not protect the integrity of the messages.
2.7.1 Types of Privacy
MOTOTRBO offers two type of privacy mechanisms - Basic and Enhanced. Both of them utilize
Motorola proprietary mechanisms/algorithms and therefore are not interoperable with other
vendor’s privacy offerings.
The main differences between Basic and Enhanced Privacy are that the Enhanced Privacy
provides higher level of protection and it supports multiple keys in a radio compared to one key in
the case of Basic Privacy.
The two privacy mechanisms are not interoperable. Both mechanisms cannot operate in a radio at
the same time. This implies that either all the digital private channels support Basic Privacy or all
the digital private channels support Enhanced Privacy. Also all the radios on a repeater must use
the same privacy mode even if they are in different groups. In direct mode, all the radios that
communicate with each other must use the same privacy mode.
The software for both co-exists in a radio and repeater. While configuring a radio or repeater using
CPS, the CPS user selects the radio-wide privacy type to be either Basic or Enhanced.
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2.7.2 Strength of the Protection Mechanism
Both Basic and Enhanced Privacy do not provide resistance against “replay attack” (i.e. an
adversary intercepts the data and retransmits it) or “traffic analysis” (i.e. disclosure of information
that can be inferred from observing the traffic patterns).
Their protection mechanism requires a key that is shared only among the intended parties. They
do not use any hardware-based cryptographic engine or a hardware-protected memory for storage
of keys.
The resistance provided by the Basic Privacy is minimal due to the following reasons:
• The Basic Privacy uses a non-cryptographic algorithm to transform plain voice/data into
protected voice/data. It is possible for an adversary to obtain the key by storing a few
Over-the-Air voice or data packets and performing few simple mathematical operations.
• The Basic Privacy uses 16 bit keys. A user selects a key from 255 predefined keys
stored in the CPS. The limited number of possible keys makes it easy for an adversary
to guess the key in-use.
The intended use of the Basic Privacy is to stop casual eavesdropping only.
The resistance provided by the Enhanced Privacy is significantly better than the resistance
provided by the Basic Privacy due to the following reasons:
• The Enhanced Privacy uses a cryptographic algorithm to transform plain voice/data into
protected voice/data. The algorithm is the well-known ARC4. (Alleged RC4) and is same
as RC4
key from Over-the-Air protected messages.
• The Enhanced Privacy uses 40 bit long keys. A radio can store up to 16 keys and the
Enhanced Privacy allows using different keys for different channels. The large number
of possible keys (approximately 1 trillion) makes it difficult for an adversary to guess the
value of a key. Note that a 40 bit long key may not provide the protection needed to
transmit valuable data such as credit card numbers.
• Using the same key, the Enhanced Privacy protects each superframe of voice or each
data packet in a different and unrelated way. This increases the resistance further.
1
. A cryptographic algorithm makes it very difficult for an adversary to obtain the
2.7.3 Scope of Protection
Both Basic and Enhanced Privacy protect only the voice and data messages (including IP/UDP
headers). The layer 2 voice and data headers, data response packets, and link control data are not
protected. This means that the source and target individual ID and Group IDs are not protected.
Control messages such as Radio Disable, Remote Monitor, Radio Check, Call Alert and the
embedded and standalone digital signaling are also not protected.
The protection is provided in all the operational modes (direct mode, repeater mode, and IP Site
Connect) and through all the communication paths between the sending radio and the destination
radio. This implies that the voice and data messages remain protected in the following situations:
1. The name “RC4” is trademarked by RSA Security. Although “unofficial” implementations are legal, but
the RC4 name cannot be used.
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• Over-the-Air, in direct mode;
• Over-the-Air and inside a repeater, in repeater mode; and
• Over-the-Air, inside repeaters, and over the backend network, in IP Site Connect.
Note that the Basic and Enhanced Privacy does not protect the voice and data messages between
a radio and its option board or between a radio and its accessory (including a MDT). Any data that
extends past the radio network is not protected. For example, text messages from field units to text
message dispatchers or e-mail addresses on a network are not protected once they leave the
destination radio (i.e. a Control Station).
Both Basic and Enhanced Privacy protect Individual voice call, Group voice call, All system call,
Emergency call, and all Packet data calls (i.e. Individual, Group, unconfirmed, and confirmed).
2.7.4 Effects on Performance
Basic Privacy uses only one key, which is known to both the sender and the receiver. This
eliminates the need to transport crypto parameters (e.g. Key Identifier) with the voice or data
payload. A voice message, in case of Basic Privacy, neither requires any modification in the
payload nor any additional headers. Therefore, the System Access Time and the audio quality of a
Basic privacy protected voice is same as that of an unprotected voice.
Enhanced Privacy uses multiple keys and a random number to ensure that the encryption data is
different for each data message and each superframe of a voice message. This requires
transporting crypto parameters (e.g. key Identifier, Initialization Vector) with the voice or data
payload. A voice message, in the case of Enhanced Privacy, requires an additional header and
replaces some of the least important bits of the voice payload with the Initialization Vector. The
additional header increases the System Access Time except when Talk Permit Tone is enabled (in
repeater mode) where the additional header replaces one of the normal voice headers. The
replacement of payload bits reduces the voice quality. Note that the reduction in voice quality is
barely noticeable.
In case of both Basic and Enhanced Privacy, a data message requires an additional header to
distinguish between an unprotected data message and a protected data message. In case of
Enhanced Privacy, the additional header is also used to transport crypto parameter. This reduces
the data throughput. For example, a typical protected confirmed location response takes 600
milliseconds compared to 540 milliseconds for an unprotected one (approximately 10% loss in
throughput).
2.7.5 User Control Over Privacy
The Customer Programming Software (CPS) allows a System Installer to select the type of privacy
(i.e. Basic and Enhanced Privacy). CPS also allows the enabling or disabling of the privacy service
of a channel. The option to toggle the privacy capability per channel can additionally be given to
the radio user by providing a menu entry or programmable button. Without the menu entry or
programmable button, the radio user is essentially “locked” to the channel’s privacy setting. It is
important to note that a user can set or reset privacy for a channel, and not for the radio. If the user
is provided with the menu entry or programmable button, and he toggles the privacy setting, only
the selected channel’s privacy setting is toggled and remains toggled even after the user changes
channels or zones. Toggling the privacy setting on a channel will not affect the privacy setting on
other channels.
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The privacy setting of a channel controls the transmit privacy setting, not the receive privacy
setting. A radio on a privacy-enabled channel always transmits protected, while a radio on a
privacy-disabled channel always transmits unprotected. However, the radio receives both
unprotected and protected regardless of the channel’s privacy setting. Any time the radio receives
a protected message, regardless of the channel’s privacy setting, the radio always tries to
unscramble or decrypt the message. If a radio is never required to receive protected messages
then it should be provisioned with a key that is different than the key(s) used by the rest of the
system. Simply setting a channel to be privacy-disabled does not stop the radio from receiving
protected messages. A radio receives a protected message correctly as long as it has the right
key.
Therefore, when one radio user on a privacy-enabled channel transmits, every radio, regardless of
its channel’s privacy-enabled or privacy-disabled status, will hear the transmission clearly if their
provisioned Privacy Key is identical to that of the transmitting radio. A radio user receiving a
protected transmission sees the green LED blinking rapidly. The receiving radio user should
consider changing the privacy setting to match that of the call initiator when replying.
In case of Basic Privacy, a system utilizes only one key and if all radios are privacy capable, it is
recommended that all radios are set to privacy enabled and equipped without the option to toggle
the privacy settings by a radio user. Since Basic Privacy does not cause any degradation in audio
quality, or decrease in performance, there is no reason for the normal user to switch between nonprivacy and privacy. Removing the option to toggle the setting from the radio user will safeguard
against any complicated privacy mismatch scenarios.
2.7.6 Privacy Indications to User
It is important for a radio user to know the privacy status (i.e. enabled or disabled) of the current
channel, and also to know if the received voice transmission is unprotected or a protected voice
transmission. There is no privacy indication for incoming protected data transmissions.
Prior to transmitting, a radio user should check the privacy setting of the current channel. On
privacy-enabled channels, an icon is shown on the front panel display of the radio when the radio
is idle.
Privacy Enabled Privacy Disabled
Upon receiving a voice transmission, the radio user can know the privacy status of the voice
transmission by observing the blinking rate of the receive LED. When receiving a protected voice
transmission, the LED blinks green but at a quicker rate than when receiving an unprotected voice
transmission.
no icon
If radio users in a call have mismatching privacy settings, but the same key, they are able to
communicate, but the transmissions are protected in only one direction. In other words, only the
transmissions from radios with privacy enabled are protected.
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The radio does not automatically negotiate privacy settings, or block transmissions that are not
protected. Therefore, it is up to the radio users to monitor the privacy indications to determine if all
the users in the call have a matched privacy setting. The radio will display the privacy setting of the
received transmission, but will blink if it does not match the transmit mode of the receiving radio.
When a privacy setting mismatch occurs, they should request the other members of the call to
switch their privacy settings to match. The radio allows users to enable or disable privacy on the
channel while on a call.
Radio users with non-display or numeric display radio models are not able to view the icon that is
shown on a privacy-enabled channel. Therefore, it is recommended that such users should not
have the option to toggle the privacy setting.
If non-display or numeric display radio users must be able to toggle between protected and
unprotected, it is recommended that this be done by programming duplicate channels, one with
privacy enabled and one without, and the user should use the dial position to toggle between
protected channels and unprotected channels. For example, dial position one may be set to
communicate with a Group in unprotected mode, and dial position two may be set to communicate
with the same group but in protected mode.
2.7.7 Key Mismatch
In case of Basic Privacy, a receiving radio assumes that the received protected transmission is
protected using the same Key that it has, because the key identifier is not sent with the message.
If the receiving radio does not have the same key as the transmitting radio, the receiving radio
cannot unprotect the transmission correctly. For voice transmissions, this results in unintelligible
audio (sometimes referred to as digital warbles) being played through the target’s speaker. For
data transmissions, this results in an unsuccessful data message transmission. This is because
the IP/UDP headers of a data message when unprotected using a wrong key fail to CRC check.
On failure of the checksum, the data message is not delivered to the application.
In case of Enhanced Privacy, the key identifier is sent with the message and if the receiving radio
does not have the key then it either remains muted (in case of voice message) or discards the data
message. If the key value associated with the key identifier is different in the sender and receiver,
due to a miss-configuration, then the voice transmissions will result in unintelligible audio and the
data transmissions will be unsuccessful.
2.7.8 Keys and Key Management
In case of Basic Privacy, a radio is capable of holding only one Privacy Key. The same key is used
to protect and unprotect voice and data transmissions over all the channels and for all call types:
Group Call, Private Call, All Call, or Emergency Call.
In case of Enhanced Privacy, a radio is capable of holding up to sixteen Privacy Keys, where keys
are associated with channels. The relationship between keys and channels is 1:0...n. (in other
words 1 to 0 or 1 to many) “0” means that keys may be provisioned into the radio but are not
associated with any channel. In this case, the keys are used to unprotect a received message but
are not used by the radio to protect a transmission.
A Privacy Key is provisioned in a radio using a CPS. The keys are not readable, editable, or
erasable by the radio user. Once a key has been chosen and programmed into a radio, the key
cannot be extracted and viewed by CPS. It can only be retained or overwritten.
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In case of Basic Privacy, a CPS user can select one of the 255 prescribed keys. These keys are
referenced by a key index from 1 to 255. Each key index references a particular 16-bit key that is
used for protecting Over-the-Air. There is no option for a “blank”, “null”, or “zero” key. In case of
Enhanced Privacy, the valid range for the value of a Key is 1 to 1,099,511,627,774 (i.e.
FFFFFFFFFE in hex). The Key values 0 and 1,099,511,627,775 (i.e. FFFFFFFFFF in hex) are
reserved and should not be used.
MOTOTRBO does not support remote or Over-the-Air programming of keys into a radio. Keys can
be programmed in a radio using only CPS. CPS supports loading of the value and identifier of a
Key into a radio either manually or from a protected archive file (in case of Enhanced Privacy
only). In case of getting the keys from a protected archive file, the CPS User selects the protected
file and provides the password. The file is unreadable without a password. The CPS is capable of
copying key(s) from one radio's archive into another radio's archive without the user needing to
retype the key for each radio.
A customer may need to change one or more keys (in the case of Enhanced Privacy) with a set of
new keys into a set of radios. Some of the reasons for changing keys are:
• Compromise of keys
• Security policy of the customer requires periodic update of keys
• Loss of a radio resulting in a concern that this may lead to compromise of keys or
eavesdropping.
The easiest way to implement a key switchover is to gather all radios and re-program them at one
go. But it may not always be possible to gather all the radios without seriously affecting day-to-day
operations.
An alternate method is to create two zones where one zone is set to unprotected while the other is
set to “protected”. The key can be changed on the protected zone and the users shall use the
unprotected zone until all radios have been updated. Once all radios have been updated, the
dispatcher informs the fielded radios to switch zones. This allows users to communicate in clear
until the all radios are provisioned, and then all the users switch keys at the same time.
A similar zone strategy can be used to perform periodic key set changeovers. For example, when
one zone has January’s keys and another duplicate zone has February’s keys. On the first of
February, the users switch to the February zone. Throughout February, the January zone is
updated with March’s keys and renamed to “March Keys”. On the first of March, the users switch,
and so cycle starts again. This makes sure that only two months of keys are compromised if a
radio is stolen or lost.
2.7.9 Multiple Keys in a Basic Privacy System
Although a radio can only use one key in a Basic privacy system at a time, a Basic privacy system
may utilize multiple keys to sub-divide a group into a set of groups. Note that this is not a
recommended configuration, and some considerations need to taken into account, if the decision
is made to utilize multiple keys in a system.
It is not recommended that Groups be sub-divided into smaller groups with the use of keys. This
results in one sub-group of users hearing unintelligible audio (or digital warbles) when the other
sub-group communicates. It is recommended that the users should be divided into Groups, and
provisioned so that a user can not transmit nor receive on the other’s Group. If users with different
keys are allowed to communicate with Basic privacy enabled, for example via a protected private
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call, a key mismatch will occur and unintelligible audio will be heard. Although these users with
different keys will never be able to communicate privately, they will be able to communicate when
privacy is disabled.
For example, two different Groups are isolated by provisioning different privacy keys. When a user
in each Group needs to communicate to each other via a private call, they must do it with privacy
disabled. If a radio user needs to communicate with both Groups via an All Call, the radio user
must transmit in clear mode so that both Groups can monitor. If users respond with privacyenabled, the user who initiated the All Call only monitors the responses protected with a matching
key.
If the system is utilizing data applications and must communicate through a control station to the
application server, all radios on a slot must have the same key or they will not all be able to
properly communicate with the control station. For similar reasons, it is not recommended to have
radios without privacy capability, i.e. older software versions, in the same Group as radios with
privacy capability. Since older radios are not provisioned with a Privacy Key, the audio will be
muted. If radios with privacy capability need to communicate to radios without privacy capability,
they will need to disable privacy before transmitting.
As a general rule, it is always recommended that groups with different privacy capabilities and
settings be placed in different Groups and on different slots.
2.7.10 Data Gateway Privacy Settings
The privacy setting of a control station acting as the data gateway to the application server is very
important for consistent data communications. This may even drive the privacy configuration of the
rest of the system.
If a system contains some privacy-capable radios and some privacy-incapable (i.e. older software
versions) radios then the control station must be privacy capable, but configured to transmit
unprotected. This way, outbound messages can be received and processed by the older radios
(not privacy capable). Note that the privacy capable radios send their data protected and the
control station will be able to decode these messages, as long as it has the proper key.
In case of Basic Privacy, there can only be one key per channel (or slot). Since the control station
can only contain one key, it cannot communicate privately to two different Groups utilizing different
keys. If a Basic Privacy system utilizes multiple keys, those users must be divided onto two
separate channels (or slots), each with their own control station utilizing the proper key. Setting the
control station to privacy disabled will not solve this problem since incoming messages such as
GPS or text messages may be protected using different keys and only one key can be used at the
control station to unprotect. Therefore, although outbound messages would be functional, inbound
messages would not be.
If users have the ability to toggle their privacy settings, it is acceptable to have the control station
set to either privacy enabled or privacy disabled, but only if their provisioned keys match. If the
control station is set to privacy enabled, and the radio is set to privacy disabled, one direction of
the data communication will be protected and the other will be unprotected. Since radios set to
privacy disabled will receive protected, and radios set to privacy enabled will receive unprotected,
the communication path will work. If important data is being transferred to and from the fixed
infrastructure, it is recommended that the control station should be set to “protected”. This will
guarantee that at least half of the data transmission will be private. Also, the system will be tolerant
if fielded radios are set to privacy disabled.
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It is recommended that all radios including control station should have same privacy settings. If the
privacy setting is enhanced privacy then the control station should have the transmit keys of all the
radios and all the radios should have the transmit key of the control station.
2.7.11 Protecting One Group’s Message from Another
There may be a need for one Group’s voice and data to be protected against another over the
same channel (same frequency and same slot). There may be some radio users who are
members of one or more of the groups. In this case, if a group not only wants to protect their
communication from intruders but also from other groups then each group should use separate
keys for protection.
The System Installer should make each group that need to be protected as “TX Group” for a
personality. The relationship between a personality and a group is 1:1. The System Installer should
associate a key to a personality. The relationship between a key and a personality is 1:1. And
therefore the relationship between a key and a group becomes 1:1. If a radio ‘X’ wants to make a
protected private call to a radio ‘Y’ and if both the radios are member of a group ‘T’ then the radio
‘X’ goes to a personality whose “TX Group” is ‘T’. If there is no group where both the radios are
member then it is not possible to send a protected message.
For a protected “All Call”, the transmitting radio should go to a specific personality and the key
associated with that personality is present in all the radios. For a protected private call, the
transmitting radio should go to a specific personality and the key associated with that personality is
present in the receiving radio.
2.7.12 Updating from Basic Privacy to Enhanced Privacy
It may not be possible for a System Installer to update all the radios from Basic Privacy to
Enhanced Privacy in one session. In such cases, the System Installer instructs all the radio users
to disable the Privacy feature and operate in clear mode. When instructed, the radio users disable
the Privacy feature using the radio front panel. All the messages are transmitted in clear.
The System Installer updates the software of radios and configures the radios for Enhanced
Privacy. Once all the radios are upgraded, the System Installer updates the software of repeaters
and configures them for Enhanced Privacy. The control stations acting as the data gateway should
also be upgraded.
The System Installer instructs all the radio users to enable the Privacy feature. The radio users
enable the Privacy feature using the radio front panel. The control stations also enable privacy. All
the messages are transmitted using Enhanced Privacy.
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2.8 Repeater Diagnostics and Control (RDAC)
Repeater Diagnostics and Control (RDAC) allows a system administrator the ability to monitor and
control repeaters within the system. The following services are provided:
1. Repeater Diagnostics
• Read Enabled/Disabled Status
• Read Analog/Digital Status
• Read Wide or Local Area Status
• Read Transmit Power (High or Low) Status
• Read Available Channels (including Currently Selected)
• Read Inbound RSSI
• Read IPv4 Address and UDP Port (required for connectivity)
2. Repeater Alarm Reporting
• Detect and Report Receiver Lock Detect Failure
• Detect and Report Transmitter Lock Detect Failure
• Detect and Report RF Power Out (only on the MTR3000 Base Station/Repeater)
• Detect and Report High VSWR Detection (only on the MTR3000 Base Station/
Repeater)
• Detect and Report RF PA Fan Failure Alarm (only on the MTR3000 Base Station/
Repeater)
• Detect and Report EEPROM Corruption (only on the MTR3000 Base Station/
Repeater)
• Detect and Report Low RF PA Voltage (only on the MTR3000 Base Station/Repeater)
• Detect and Report FRU Incompatibility Alarms (e.g. PA and exciter are incompatible)
(only on the MTR3000 Base Station/Repeater)
• Detect and Report Overheating (for XPR 8300 refers to system overheating, and for
MTR3000 overheating refers to RF PA overheating)
• Detect and Report AC Power Failure
• Detect and Report Main Fan Failure (only on the XPR 8300 Repeater)
3. Repeater Control
• Change Enabled or Disabled Status
• Change Channels
• Change Transmit Power Level (High or Low)
• Reset Repeater
• Knockdown Repeater
The RDAC application can be configured to work over the network via IP or locally via USB.
When working over the IP network, the application communicates with all repeaters within an IP
Site Connect system using the same link establishment process that the repeaters utilize.
Therefore, it benefits from the existing link establishment and authentication utilized between
repeaters. All services in the list above are available through the RDAC application.
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When working locally, the RDAC application connects to a single repeater via USB. The repeater
control services are not available via the USB interface through the RDAC application.
The user also has access to the repeaters external GPIO pins. External equipment (or existing
remote adapters and desksets) can be configured to set or read the GPIO pins to allow access to
the repeater control services as well as access to indications that a minor or major alarm has
occurred. The access to these GPIO pins further allows the radio installer to utilize the alarm pin
and enable/disable pin to create a redundant switch over configuration. Alarm Reporting and
Control is available using the GPIO pins.
Note that any combination of RDAC connected over the Network, RDAC connected via USB, or
connections via GPIO are supported.
The ability to change the repeater channel can be utilized to toggle channel parameters between
predetermined settings. For example, if the repeater contains one channel that is in analog mode
and another channel that is in digital mode, changing the channel between these channels
essentially changes the mode from analog to digital. The same strategy can be used to toggle the
wide area and local setting of a timeslot. One personality could be provisioned for two wide area
channels, while the next has one wide and one local channel. Other channel parameters can be
changed using the same strategy.
It is important to note that many control operations require the repeater to perform a reset before
processing the control operation. During the reset the repeater will not be able to service inbound
transmissions from fielded radios. Also note that the repeater takes no consideration to the
ongoing traffic when instructed to perform a control operation. In other words if a call is in progress
(group call, individual call, all call, emergency call, data call, etc.) the repeaters perform the control
operation and drop the call in progress. In addition, the IP connection between the repeater and
the RDAC will be temporarily severed while the repeater is rebooting. The connection must be reestablished before additional operations can be performed. This should be taken into
consideration before performing any control functions on an active repeater.
In addition to the repeater reporting alarms to RDAC application and setting the GPIO alarm pins
accordingly, it is important to note that it also takes action when major alarms are received. The
repeater will perform a reset after a major alarm is reported as an attempt to clear the alarm. If the
alarm is not clear after reset it will reset again. This will continue until the alarm is cleared or the
repeater is locked (3 major alarms). Once 3 major alarms have been reported, the repeater will
enter the Locked state and set the Major Alarm Pin. At this time all the LEDs on the Repeater front
panel will be solid. While in the locked state, the repeater will not service any calls Over-the-Air.
The RDAC application will display the locked state and have the ability to retrieve logs.
In order to exit the locked state, the repeater must be read and written to with the CPS to reset the
major alarm counter. This is automatically done when CPS writes a codeplug to the repeater. Note
that 3 major alarms almost certainly means that there is a hardware problem that should be
addressed prior to clearing the locked state.
Alarms
1
are categorized as shown below:
• Major Alarms – Receiver and Transmit Lock Detect Failure, EEPROM Corruption, FRU
Incompatibility, VSWR higher than 5.1, RF Power Out
1. It must be noted that there are different severity for the VSWR, RF Power Out, and EEPROM Corruption
alarms.
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• Minor Alarms – Overheating, AC Power Failure, Main Fan Failure, RF Power Out, High
VSWR Detection, RF PA Fan Failure Alarm, Low RF PA Voltage, EEPROM Corruption
2.8.1 Connecting Remotely via the Network
Connecting RDAC via the network allows access to all repeaters in an IP Site Connect system. If a
system has more than one wide area system (i.e. more than one Master repeater) then the RDAC
application is required to know the static IP address and UDP port of each of the Master repeater.
A single RDAC application supports up to eight IP Site Connect systems (i.e. eight Master
repeaters). It will learn the addresses of the other repeaters through communication with each
Master. Similar to repeater communication, the RDAC application should not require any specific
firewall configuration. It will require the appropriate authentication be entered that is being utilized
by the repeaters in the IP Site Connect system. When connecting to multiple IP Site Connect or
Capacity Plus systems, RDAC must be configured with a different UDP port for each Master.
Although the network connection is designed for “connecting remotely”, a local network connection
in close proximity to the repeater is supported.
The RDAC-IP application can communicate with enabled and disabled repeaters, knockdowned
repeaters, digital and analog repeaters, and wide and local area repeaters. As long as they are on
the network and communicating with the same Master repeater that the RDAC application is
communicating with, they will be controllable via the application.
It is important to note that over-use (or misuse) of RDAC diagnostics could cause strain to the
network link and therefore, cause voice degradation. For example, numerous requests for status
or error logs could cause excess traffic on a network link which could delay voice through the
network. Please review the network bandwidth considerations in later chapters.
2.8.2 Connecting Locally via the USB
Connecting RDAC locally via the USB provides the user with all the services of RDAC but only
allows access to the local repeater. This connection is very useful if the repeater is in close
proximity to the dispatch center or while performing service or trouble shooting locally.
2.8.3 Connecting Locally via GPIO Lines
Connecting locally via GPIO lines only allows access to the local repeater. The user has access to
the repeater control services as well as access to indications that a minor or major alarm has
occurred from the GPIO lines. The GPIO lines can be configured in various ways and can be
integrated to communicate with a variety of external equipment.
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A custom cable is needed to connect the repeater accessory port to the outside control device.
Below is an example of one configuration. Note that the pin out of the cable is dependent on how
the GPIO lines are provisioned via CPS.
Repeater
GPIO Pins
GPIO Connections
Custom Cable
Desk Set
Remote A dapter
Standard Cable
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2.8.3.1 RDAC Local Settings Rear Accessory Port CPS Programmable Pins
The rear accessory also has some pins that can be programmed to specific input/output functions.
These pins can be programmed to either active high or low. See the table below for descriptions of
these functions available for each GPIO pin.
CPS Programmable Pins Description
Major Alarm (Locked State)
Minor Alarm
Repeater Disable
Tx Power Level High
Repeater Knockdown
Channel Change
This output pin is used to report a major alarm has happened 3 times, been
reset three times, and the repeater is in now locked state.
This output pin is used to report minor alarm(s) is happening on the
repeater.
Asserting this input pin triggers the repeater to enter disabled state. In this
state, the repeater can not execute repeat functions.
Releasing this input pin will revert the repeater back to enabled state where
the repeaters can start repeating calls.
Asserting this input pin triggers the repeater to change the TX power level
to be high.
Releasing this input pin will revert the repeater back to TX low level low.
Asserting this input pin triggers the repeater to temporarily enter Repeat
Path Disable Mode. In this mode, the repeater’s transmitter will only be
enabled by the external PTT and the audio source will be the Tx Audio
Input pin.
Releasing this input pin will revert the repeater back to Normal Mode where
the repeaters transmitter can be activated by a qualified RF signal on the
receive frequency.
*Note that repeater knockdown is not supported in digital mode.
*In Dynamic Mixed Mode system, this feature is not supported during an
ongoing digital transmission.
There are up to 4 pins that can be configured and used for channel change.
The repeater can support up to 16 channels.
Asserting this input pin represents 1.
Releasing this input pin represents 0.
0000 represents first channel, 1111 represent the last channel.
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90 System Feature Overview
2.8.4 Redundant Repeater Setup
By using the alarm feature and control feature together, it is possible to setup redundant repeaters.
So that when one repeater fails, the standby repeater can take over the repeat function.
Before installation, both repeaters are programmed with the same channel information. The
installer configures one repeater as primary repeater and the other one as standby repeater. For
the primary repeater, the installer configures one GPIO pin for major alarm reporting and
configures the pin’s polarity. For the standby repeater, the installer configures one of its GPIO pins
as repeater disabled control input pin and its polarity opposite of the primary repeater’s alarm pin
polarity. When the primary repeater’s alarm pin becomes active it deactivates the disabled pin and
the standby repeater becomes enabled. The antenna system is connected to the primary repeater
and also connected to an antenna switch. The antenna switch is external to the repeater
hardware. The installer connects the primary repeater’s alarm pin (output pin) and standby
repeater’s repeater disable pin (input pin) and the antenna switch all together. The installer powers
on the primary repeater first and verifies it is working with no major alarm reported. Then the
installer powers on the standby repeater.
Antenna Switch
Repeater TX/RX Repeater TX/RX
GPIO Pins
Major Alarm Pin
GPIO Pins
Repeater Disabled
Primary Repeater Standby Repeater
When a major alarm happens three times in the primary repeater and the repeater enters the
locked state, the primary repeater will set the major alarm GPIO pin to active level. The standby
repeater detects the disable pin is changed to inactive level and it becomes enabled. The antenna
switch is also triggered which changes the antenna to the now active repeater.
Once the fault in the primary repeater is addressed, the repeater is removed from the locked state
and reset, the primary repeater will enabled and again become the primary repeater. The standby
repeater will become disabled.
March 2010 6880309T12
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