GE MDS 4790M Installation And Operation Manual

MDS 4790M

400 MHz Master Station Radio

Installation and Operation Guide

for MPT 1411 Applications

GE MDS 05-3628A01, Rev. B

AUGUST 2008

QUICK START GUIDE

1. Install and connect the antenna system to the radio (page 10).

• Use an appropriate antenna aimed at the associated station.

• Use low-loss feedline suited for 400 MHz. Keep the feedline as short as possible.

2. Connect the backup battery, if equipped (page 14).

3. Connect the host computer to the DATA connector on the rear panel (page 17).

4. Verify proper input voltage level and connect power to the radio. Set the power switch(es) to
ON.

5. Observe front panel indicators for proper operation.

Invisible place holder

ACTIVE (green)—This transceiver board (A or B) is the selected unit.
STBY (yellow)—This transceiver board (A or B) is the standby unit (protected version only).
ALARM (red)—General fault not covered by the other alarm categories (RX ALR, TX ALR, I/O ALR).
RX ALR (red)—Difficulty receiving. May be due to an antenna problem, receiver fault, or other condi-

tion causing a low received signal level.

TX ALR (red)—Fault with the transmit circuitry.
I/O ALR (red)—The data rate or format of data at the data interface conne ctor is incomp atible with the

radio settings.

TABLE OF CONTENTS

1.0 INTRODUCTION......................................................................... 1

2.0 PRODUCT DESCRIPTION ......................................................... 1

2.1 Network-Wide Diagnostics ...............................................................3

2.2 Redundant versus Non-redundant Operation ..................................3

2.3 Applications ......................................................................................3

Basic MAS Master Station Operation.................................................4

Repeater and Polling Remote Operation............................................4

2.4 Features ...........................................................................................5

2.5 Accessories ......................................................................................5

2.6 Model Number Codes ......................................................................6

2.7 Terms and Abbreviations ..................................................................6

3.0 INSTALLATION PLANNING........................................................ 8

3.1 General Requirements .....................................................................8

Site Selection......................................................................................8

A Word About Interference.................................................................9

3.2 Antenna and Feedline Selection ....................................................10

Antenna System ...............................................................................10

Feedline Selection.................................................. .... ... ... ................10

4.0 INSTALLATION PROCEDURES ................................................11

4.1 Unpacking and Inspection .... ..........................................................11

4.2 Mounting the Radio ........................................................................12

Rack Mounting..................................................................................12

Tabletop Mounting............................... ... ... .......................................12

Remote Front Panel Mounting—Optional Configuration ..................12

4.3 Primary Power ................................................................................13

AC-Powered Units............................................................................13

DC-Powered Units............................................................................13

4.4 Battery Power .................................................................................14

Battery Connection................................................. .... ... ...................15

Low Voltage Disconnect Feature......................................................15

Battery Reset Switch (SW1).............................................................16

4.5 Antenna System .............................................................................16

Antenna Installation..........................................................................16

Feedline Installation............. ... ... .... ... ... ... ... .......................................16

4.6 Interface Wiring Connections .........................................................17

Data Connector ................................................................................17

Diagnostics.......................................................................................19

Analog Orderwire.......... .... ... ....................................... ... ... ... ... .... ... ...19

Alarm Contacts and Battery Back-up Connections...........................19

4-Wire Audio Connector ...................................................................20

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide i

4.7 Post Installation Checks .................................................................20

5.0 START-UP AND OPERATION................................................... 21

5.1 Initial Startup ..................................................................................21

Normal Indications......................... ...................................................21

Maximizing RSSI..............................................................................21

5.2 Front Panel Indicators ....................................................................21

LED Indicators..................................................................................22

Front Panel Display....................... ... ... ... ... .... ... ... ... .... ......................23

6.0 DIAGNOSTICS AND CONTROL............................................... 23

6.1 PC Connection ...............................................................................24

6.2 PC Command Summaries .............................................................24

Commands and Command Parameters...........................................25

6.3 Detailed Command Descriptions ....................................................28

ALARM .............................................................................................28

AMASK [0000 0000–FFFF FFFF] ....................................................30

ASENSE [HI/LO]...............................................................................31

BAUD [xxxxx abc]................ ... ... .... ... ...................................... .... ... ...31

BUFF [ON/OFF]................................................................................31

CKEY [ON/OFF] ...............................................................................32

CTS [0-255]......................................................................................32

DATAKEY [ON/OFF].........................................................................33

DATE [mmm dd yyyy] .......................................................................33

DKEY................................................................................................33

DLINK [ON/OFF/xxxx] ......... ... ... ....................................... ... ... .... ... ...33

DMGAP [xx].................. .... ... ....................................... ... ... ... ... ..........34

DTYPE [NODE/ROOT/GATE/PEER]................................................34

DUMP...............................................................................................34

EMP [ON/OFF] .................................................................................34

HREV................................................................................................35

INIT...................................................................................................35

KEY ..................................................................................................35

LOG [CLR]................. ... .... ...................................... .... ......................36

MODEL.............................................................................................36

MODEM [9600M, MPT1411].............................................................36

NMASK [0000 0000–FFFF FFFF]....................................................36

OPT..................................................................................................37

OWM [xxxxx] ................................. ... ... ... ... .......................................37

OWN [xxxxx].....................................................................................37

PROG...............................................................................................37

PROGACT........................................................................................37

PTT [0-255]............. ....................................... ... ... ... ..........................38

RADIO [A/B/AUTO]................................. ... .......................................38

REPEATER [ON/OFF]......................................................................38

RSSI, RSSI!......................................................................................38

RTU [ON/OFF/0-80]..........................................................................39

RX [xxx] ............................................................................................39

RXMUTE ..........................................................................................39

RXLEVEL [–20 to +3] .................................... ...................................39

ii MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

RXPAD [ON/OFF].............................................................................40

RXTOT [NONE, 1-1440]...................................................................40

SCD [0-255]...................... ... ... ... .... ... ... ....................................... ... ...40

SER..................................................................................................40

SHOW [DC/PWR/CURRENT/RADIO]..............................................40

SNR, SNR! .......................................................................................41

SREV................................................................................................41

STAT.................................................................................................41

TEMP................................................................................................42

TIME [hh:mm:ss] ..............................................................................43

TOT [ON/OFF, 1-255].......................................................................43

TX [xxxx]...........................................................................................43

TXGAIN [ON/OFF]............................................................................44

TXLEVEL [–20 to +3, AUTO]............................................................44

UNIT [10000–65000]........................... ... ... .... ... ... ... ..........................44

6.4 Configuration and Programming using the Front Panel .................44

Programming and Control Buttons ...................................................47

Navigating Through the Front Panel Screens ..................................47

Switching the Front Panel Display to Configuration Mode ...............48

Use of Control Buttons in Configuration Mode........................... ... ...48

Making Changes to Radio Functions................................................48

6.5 Screen Descriptions .......................................................................49

Group 1—Startup Screen and Menu Directory (page 53).................49

Group 2—Configuration Screens (page 53).....................................49

Group 3—Diagnostic Screens (page 61)..........................................49

Group 4—Event Log (page 62) ........................................................50

7.0 LOCAL & NETWORK-WIDE PROBLEM SOLVING.................. 63

7.1 Local Problem-Solving ................................................................... 63

Problem-Solving with LED Indicators ...............................................63

Problem-Solving Using a Connected PC..........................................64

Problem-Solving Using the Front Panel Display...............................64

System Bench Testing Set-up ..........................................................65

7.2 Performing Network-Wide Radio Diagnostics ............. ... ... ... .... ... ...65

7.3 Replacing Assemblies ....................................................................67

Transceiver Board and Power Supply Assemblies.............. ... .... ... ...67

Front Panel....................................................... ... ... .... ... ... ... ... .... ... ...68

Internal Duplexer..............................................................................68

Antenna Switch Module....................................................................70

7.4 Cooling Fan Maintenance .............................................................71

8.0 TECHNICAL REFERENCE.......................................................72

8.1 Technical Specifications ..........................................................72

8.2 RF Propagation Planning ...............................................................74

Fresnel Zone Clearance...................................................................74

Earth Curvature ................................................................................75

Fade Margins................ .... ...................................... .... ... ... ... ... .... ......75

Calculating Path Loss.......................................................................75

8.3 Formulas for System Planning .......................................................76

Free Space Path Loss............................................ .... ... ... ... ... ..........76

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide iii

RF Exposure

Fresnel Zone Boundary....................................................................76

Theoretical Signal Strength ..............................................................76

Probability of System Fading......................... ... ... ... .... ... ... ... ... .... ... ...76

8.4 Frequency Reference Chart ...........................................................77

8.5 dBm-Volts-watts Conversion Chart ................................................80

Copyright Notice

This Installation and Operation Guide and all software described herein
are protected by copyright: 2008 GE MDS, LLC. All rights reserved.

GE MDS reserves its right to correct any errors and omissions.

Operational Safety Notices

The radio equipment described in this guide emits radio frequency
energy. Although the power level is low, the concentrated energy from
a directional antenna may pose a health hazard. Do not allow people to
come in close proximity to the front of the antenna when the transmitter
is operating.

This manual is intended to guide a professional installer to install,
operate and perform basic system maintenance on the described radio.

ISO 9001 Registration

GE MDS' adherence to this internationally accepted quality system stan­dard provides one of the strongest assurances of product and service
quality available.

GE MDS Quality Policy Statement

We, the employees of GE MDS, are committed to achieving total cus­tomer satisfaction in everything we do.

Total Customer Satisfaction in:

• Conception, design, manufacture and marketing of our products.

• Services and support we provide to our internal and external
customers.

Total Customer Satisfaction Achieved Through:

• Processes that are well documented and minimize variations.

• Partnering with suppliers who are committed to providing quality and

• Measuring our performance against customer expectations and

• Commitment to continuous improvement and employee involvement.

iv MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

service.

industry leaders.

Environmental Information

The manufacture of this equipment has required the extraction and use
of natural resources. Improper disposal may contaminate the environ­ment and present a health risk due to hazardous substances contained
within. To avoid dissemination of these substances into our environ­ment, and to limit the demand on natural resources, we encourage you
to use the appropriate recycling systems for disposal. These systems will
reuse or recycle most of the materials found in this equipment in a sound
way. Please contact GE MDS or your supplier for more information on
the proper disposal of this equipment.

Notice

While every reasonable effort has been made to ensure the accuracy of
this manual, product improvements may result in minor differences
between the manual and the product shipped to you. If you have addi­tional questions or need an exact specification for a product, please con­tact our Customer Service Team using the information at the back of this
guide. In addition, manual updates can often be found on the GE MDS
Web site at www.GEmds.com.

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide v

vi MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

1.0 INTRODUCTION

This guide presents installation and operating instructions for the MDS 4790M
master station (scanner) radio. It begins with an overall description of the
radio’s features and is followed by the steps required to install the radio and
place it into normal operation.

Additionally, the guide contains troubleshooting tips for resolving system
difficulties that may be encountered. After you install the radio, we
recommend keeping this guide near the radio for future reference.

2.0 PRODUCT DESCRIPTION

The MDS 4790M master station (Figure 1) is a full duplex radio designed to
operate with MDS 4710 remote (outstation) transceivers in the fixed telemetry
and telecontrol radio services bands of 457.5 to 458.5 MHz and 463.0 to

464.0 MHz. It is designed for compliance with the United Kingdom’s MPT

1411 specifications for radio performance and frequency assignment criteria.
Typical applications include utility Supervisory Control and Data Acquisition

(SCADA), distribution automation, online transactional processing and other
point-to-multipoint applications. The radio is available in either a redundant
configuration or a non-redundant configuration. Refer to Section 2.2,
Redundant versus Non-redundant Operation, beginning on page 3 for further
description.

The radio uses microprocessor control and Digital Signal Processing (DSP)
technology to provide highly reliable data communications even under adverse
conditions. DSP adapts to differences between components from unit to unit,
and ensures consistent and repeatable performance in ambient temperatures
from –30 to +60 degrees Celsius. The use of Digital Signal Processing
eliminates the variations in modem operation that can degrade the performance
of analog circuits.

The radio is designed for trouble-free operation with data equipment provided
by other manufacturers, including Remote Terminal Units (RTUs), flow
computers, automatic banking machines, programmable logic controllers
(PLCs), and others.

NOTE: Some features may not be available on all radios, based on the

options purchased. Consult the factory for information on feature
upgrades or available accessories.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 1

Invisible place holder

Figure 1. MDS 4790M Master Station

All assemblies, including the duplexer and power supply, are contained in the
radio’s compact (2RU high) enclosure. The radio’s compact size allows it to fit
into most existing systems, in either tabletop or rack mounting arrangements.
Connectors are provided on the rear panel for easy connection of power,
antenna, data, alarm and diagnostic functions.

2 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

2.1 Network-Wide Diagnostics

Newer GE MDS remote and master station radios, including the MDS 4790M,
offer network-wide diagnostics capability. Network-wide diagnostics
communications is a modern, packetized mode that has several advantages
over DTMF diagnostics communications (used by older GE MDS radios):

• Diagnostic data can be gathered over a large radio network without
disrupting system communications flow.

• When required, diagnostics communications speed can be increased
by actively collecting diagnostic data.

• Diagnostic data for each radio in the network can be accessed from
any radio diagnostics port in the network.

• Certain messages can be broadcast to all radios in the system
simultaneously.

The master station can be used to poll remote radios in its radio system for
diagnostic data. For more information on the implementation of network
diagnostics, refer to the GE MDS Network-Wide Diagnostics Handbook (P/N
05-3467A01).

2.2 Redundant versus Non-redundant Operation

A redundant configuration means that the master station has two complete
transceiver boards installed in the enclosure. In the event of a primary board
failure, the controlling logic causes a switch-over to the stand-by transceiver
board. The redundant transceiver configuration has a stand-by transceiver
board that is constantly operating and its operational readiness is monitored.
However, the transmitter power amplifier in the stand-by transceiver board is
not operating when it is in stand-by mode.

In a non-redundant configuration, there is only one transceiver board installed
in the “A” slot of the enclosure, and back-up transceiver board operation is not
possible.

Transceiver boards may be moved from one master station to another, or an
additional transceiver board may be added to a non-redundant master station.
You do not need to specify redundant or non-redundant op era tion , or se lec t the
active transceiver board. Installing or replacing a transceiver board will cause
the boards to communicate briefly with each other to establish which board will
operate as the active board and which operates as the stand-by. For more
information, see “Transceiver Board and Power S upply Assemblies” on page 67.

2.3 Applications

The master station is designed for point-to-multipoint data tr ansmission in utility
monitoring systems, telecommunications networks, and transactional data
applications. An MAS network provides commu nications between a central host
computer and remote terminal units (RTUs) or other data collection devices. The
operation of the radio system is transparent to the computer equipment.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 3

Basic MAS Master Station Operation

Figure 2 shows a typical point-to-multipoint system using an MDS 4790M
master station.

The most basic system consists of a central master station and several
associated remote units, as shown in Figure 2.

REMOTE RADIO

RTU

RTU

REMOTE RADIO

SWC OFF

PWR

ID
IA
G

1
3
.8 V

D

C
–
+

–

REMOTE RADIO

SWC OFF

PW

R

ID
IA
G

1

3.
8
VDC
+
–

–

RTU

CONTINUOUSLY

KEYED

MDS MASTER

STATION

HOST SYSTEM

Figure 2. Typical MAS Network

PW

R

ID
IA
G

13.8 VDC
–
+

–

RTU

SWC OFF

PWR

REMOTE RADIO

RTU

PWR

ID
IA
G

REMOTE RADIO

ID
IAG

1

3.8 V
D
C

+ –

–

SWC OFF

13.8
VD
C

–
+

–

SWC OFF

Repeater and Polling Remote Operation

An MAS system using repeater and polling-remote radios is shown in Figure 3.
Notice that the polling remote radio is operating in half-duplex mode and the
repeater is operating in full-duplex mode. Configuring the radio for repeater
operation can be as simple as typing

REPEA TER ON with a PC connected to the

rear panel diagnostic port. (See “DIAGNOSTICS AND CONTROL” on page
23 for details.)

REMOTE RADIO

RTU

RTU

TX LOW
RX HIGH

REMOTE RADIO

PWR

IDIAG

1
3
.8
V
DC
–
+

–

TX LOW
RX HIGH

REMOTE RADIO

PWR

I
D
I
A
G

13.8 VDC
+ –

–

TX LOW
RX HIGH

TX HIGH
RX LOW

CONTINUOUSLY

KEYED

REPEATER

RTU

P
W

R

I
DIAG

1
3
.8
VD

C
–
+

–

RTU

TX LOW
RX HIGH

RTU

PW

R

REMOTE RADIO

P
WR

ID
I
A
G

13.8 VDC
–
+

–

REMOTE RADIO

TX LOW
RX HIGH

IDI

A
G
1
3

.
8 V
DC

–

+

–

TX LOW
RX HIGH

4 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

POLLING REMOTE

HALF-DUPLEX

SWITCHED CARRIER

HOST SYSTEM

Figure 3. Typical Repeater and Polling-Remote Network

Simplex and Switched Carrier Operation

System-wide simplex operation is achieved by switching the master station
carrier on to transmit, then off to receive. The same frequency is used for both
transmit and receive.

Switched carrier, half-duplex mode is also achieved by switching the master
station carrier on to transmit, then off to receive. However, different
frequencies are used for transmit and receive.

2.4 Features

Reliability is a hallmark of the MDS 4790M design. The radio employs a
one-piece transceiver board which minimizes RF losses and eliminates the
need for inter-board cabling. This also allows easy plug-in replacement should
servicing become necessary.

In addition, the optional redundant version of the radio includes redundant
transceiver boards and power supply modules that automatically become active
in the event of a failure in either of the transceiver boards or power supplies.
This ensures continued operation in the event of most transceiver board failures.

The following list highlights many of the radio’s key features. For a full listing of
specifications, see Section 8.1,

Technical Specifications

• Operation from 24, 48, or 125 V dc; or 90 to 267 V ac mains

• Configuration, control and diagnostics from front panel display or
connected PC

• Remote diagnostics via a connected PC and radio software

• Time stamping of alarms and major events

• Flexible mounting (rack or table); front panel can optionally be
mounted separately from unit

, beginning on page 72.

2.5 Accessories

The radio can be used with one or more of the accessories listed in Table 1.
GE MDS publishes an Accessories Selection Guide which lists a complete

array of additional items for use with this product. Please contact your factory
representative or visit

Option Description Part No.

Diagnostics and
Control Software

Diagnostic and
Control Interface
Cable

Auxiliary Front Panel
Mounting Bracket

Orderwire Handset Allows orderwire communications with

www.GEmds.com to obtain a copy of this guide.

Table 1. Radio Accessories

Computer software that allows PC control,
diagnostics, and software upgrades.

Allows connection of a PC for control and
diagnostics and of the radio (DB-9 to DB-9).

Allows rack mounting of the detachable front
panel.

remote radios.

03-3475A01

97-1971A04

82-3189A01

12-1307A01

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 5

THIS INFORMATION IS
SUBJECT TO CHANGE.

DO NOT USE FOR
PRODUCT ORDERING.

2.6 Model Number Codes

The radio model number is printed on the serial number label, which is affixed
to the radio chassis. The following figures show the significance of the
characters in the model number string for standard models. Contact the factory
for specific information on optional configurations.

Invisible place holder

DUPLEXER

(0) None (Ext. wiring)

MODE

(N) Non -Redundant
(R) Redundant

4790M

(2) 400-512 MHz (5-30 MHz Split)
(B) Simplex 430-512 MHz
(S) None (Int. wiring)

BANDWIDTH

(1) 12.5 kHz

RECEIVE FREQ.

(J) 457.5-458.5 MHz
(K) 463.0-464.0 MHz

AGENCY

(N) N/A

SAFETY CERT.

(N) N/A

OPERATION

(B) Base
(R) Remote
(P) Repeater

INPUT VOLTAGE

(1) 24 VDC
(2) 48 VDC
(3) 24-48 VDC
(A) 110/220 VAC W/O Batt.
(B) 110/220 VAC W/ Batt.
125 VAC to 12 VDC W/ Ext. Converter

MODEM

(B) 9600 BPS
(MPT 1411)

DIAGNOSTICS

(0) None
(1) Network wide

TRANSMIT FREQ.

(D) 457.5-458.5 MHz
(E) 463.0-464.0 MHz

FEATURES

(0) Full
(D) Demo

Figure 4. MDS 4790M Model Number Codes

2.7 Terms and Abbreviations

If you are new to digital radio systems, some of the terms used in this guide
may be unfamiliar. The glossary below defines many of these terms and will
prove helpful in understanding radio operation.

Active Messaging—This is a mode of diagnostic gathering that may interrupt
SCADA system polling communications (contrast with passive messaging).
Active (or intrusive) messaging is much faster than passive messaging because
it is not dependent upon the RTU polling cycle.

BERT—Bit-error rate test. The results of a BERT are normally expressed as a
ratio (power of 10) of the number of bits received in error compared to the total
number received.

BER—Bit-error rate. See also BERT.
Bit—Binary digit. The smallest unit of digital data, often represented by a one

or a zero. Eight bits usually comprise a byte.
bps—Bits-per-second. A measure of the information transfer rate of digital

data across a communication channel.

Byte—A digital “word” usually made up of eight bits.
dBi—Decibels of gain relative to an isotropic radiator. (A hypothetical antenna

which radiates equally in all directions.) Used to express antenna gain.
dBm—Decibels relative to one milliwatt. An absolute unit used to measure

signal power, as in transmitter power output or received signal strength.

6 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

DCE— Data (circuit terminating) Communications Equipment. In data
communications terminology, this is the “modem” side of a
computer-to-modem connection. The transceiver board is a DCE device which
is designed to connect to a DTE device.

Decibel (dB)—A measure of the ratio between two signal levels. Frequently
used to express the gain or loss of a system.

DSP—Digital Signal Processing. Advanced circuit technique to increase radio
performance, primarily in modulation and demodulation.

DTE—Data Terminal Equipment. In data communications terminology, this
is the computer side of a computer-to-modem connection. (Connects to the
DCE device.)

Fade Margin—The maximum tolerable reduction in received signal strength
which still provides an acceptable signal quality. This compensates for reduced
signal strength due to multipath, slight antenna movement or changing
atmospheric losses. Expressed in decibels.

Frame—A segment of data that adheres to a specific data protocol and
contains definite start and end points. It provides a method of synchronizing
transmissions.

Fresnel Zone—A point of maximum width or girth of the transmitte d radio
signal. Obstructions in this region (the “first Fresnel zone”) can have a
detrimental effect on reception quality. As a general rule, 60 percent of the first
Fresnel zone should be free of obstructions in a well-designed system.
(Additional considerations are also required when planning an RF path. A
detailed discussion of the subject is presented in Section 8.2, RF Propagation
Planning, beginning on page 74.)

Half-Power Beamwidth—The customary way of measuring the width of a
directional antenna’s radiation pattern. This beamwidth is measured in degrees
between the half-power points (the point at which the power is reduced 3 dB
with respect to the main beam).

kbps—Kilobits-per-second.
Master Station (Scanner)—Radio which is connected to the host computer.

It is the point at which polling enters the network.
Menu Directory—Front panel display screen that is the entry point to screens

for displaying radio status and programming the radio. It contains the main
menu items Configuration, Diagnostics, and Event Log.

Multipath Fading—Signals arriving at the receiver out of phase, which have
a tendency to cancel each other. It is caused by reflections of the transmitted
wave and results in distortion at the receiver or weak received signal strength.

Network-Wide Diagnostics—An advanced method of controlling and
interrogating GE MDS radios in a radio network.

Non-intrusive diagnostics—See Passive messaging.
Passive messaging—This is a mode of diagnostic gathering that does not

interrupt SCADA system polling communications. Diagnostic data is collected
non-intrusively over a period of time; polling messages are carried with
SCADA system data (contrast with active messaging).

Payload data—This is the application’s user communication data which is
sent over the radio network. It is the radio data that is the primary purpose of
the radio communications.

Remote Station (Outstation)—A radio in a network that communicates with
an associated master station.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 7

RSSI—Received signal strength indication. Expressed in dBm.
RTU—Remote Terminal Unit. A data collection device installed at a remote

radio site. An internal RTU simulator is provided with the radio to isolate
faults to either the external RTU or the radio. For more information see “RTU
[ON/OFF/0-80]” on page 39

SNR—Signal-to-noise ratio. Expressed in decibels (dB).
SWR—Standing Wave Ratio. A parameter related to the ratio between

forward transmitter power and the reflected power from the antenna system.
As a general guideline, reflected power should not exceed 10% of the forward
power (≈ 2:1 SWR).

3.0 INSTALLATION PLANNING

The installation of the radio is not difficult, but it does require some planning
to ensure reliability and efficiency. This section provides tips for selecting an
appropriate site, choosing antennas and feedlines, and minimizing the chance
of interference. This material should be reviewed before beginning equipment
installation.

3.1 General Requirements

There are three main requirements for installing the radio—adequate and
stable primary power, a good antenna system, and the correct interface
between the radio and the data device. Figure 5 shows a typical station
arrangement.

Site Selection

Invisible place holder

OMNIDIRECTIONAL

ANTENNA

HOST COMPUTER

DIAGNOSTICS

COMPUTER

LOW LOSS

COAXIAL CABLE

TO INPUT

POWER SOURCE

Figure 5. Typical Station Arrangement

For a successful installation, careful thought must be given to selecting the site
for the master station and the remote radios. Suitable sites should offer:

8 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

• An antenna location that provides an unobstructed path to all the
remote radios in the system

• A source of adequate and stable primary power

• Suitable entrances for antenna, interface or other required cabling.

These requirements can be quickly determined in most cases. A possible
exception is the first item—verifying that an unobstructed transmission path
exists. UHF radio signals travel primarily by line-of-sight, and obstructions
between the sending and receiving stations will affect system performance.

If you are not familiar with the effects of terrain and other obstructions on radio
transmission, the following discussion will provide helpful background.

Terrain and Signal Strength

A line-of-sight path between stations is highly desirable and provides the most
reliable communications link in all cases. A line-of-sight path can often be
achieved by mounting each station antenna on a tower or other elevated structure
that raises it high enough to clear surrounding terrain and other obstructions.

The requirement for a clear transmission path depends on the distance to be
covered by the system. If the system is to cover only a limited distance, say 5
km, then some obstructions in the transmission path may be tolerable. For
longer range systems, any obstruction could compromise the performance of
the system, or block transmission entirely.

The signal strength at the receiver must exceed the receiver sensitivity by an
amount known as the fade margin (defined on page 7) to provide reliable
operation under various conditions.

Section 8.2, RF Propagation Planning, beginning on page 74 includes a
detailed discussion of path planning, and should be reviewed before beginning
an installation. Computer software is also available for this purpose that can
greatly simplify the steps involved in planning a path.

On-the-Air Test

If you’ve analysed the proposed transmission path and feel that it is acceptable,
an on-the-air test of the equipment and path should be conducted. This not only
verifies the path study results, but allows you to see firsthand the factors
involved at each installation site.

The test can be performed by installing a radio at each end of the proposed link
and checking the RSSI value reported at the radio’s front panel display. (See
“Front Panel Indicators” on page 21 for procedures.) If adequate signal strength
cannot be obtained, it may be necessary to mount the station antennas higher,
use higher gain antennas, or select a different site for one or both stations.

To prepare the equipment for an on-the-air test, follow the general installation
and operation procedures given in this guide and become familiar with the
operating instructions given in Section 5.0, START-UP AND OPERATION,
beginning on page 21.

A Word About Interference

Interference is possible in any radio system. However, since the radio is
designed for use in a licensed system, interference is less likely because
geographic location and existing operating frequencies are normally taken into
account when allocating frequencies.

The risk of interference can be further reduced through prudent system design and
configuration. Allow adequate separation between frequencies and radio systems.

Keep the following points in mind when setting up your radio system:

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 9

1. Systems installed in lightly populated areas are least likely to encounter
interference; those in urban and suburban environments are more likely to
be affected by other devices operating in the 400 MHz frequency band and
adjacent services.

2. Directional antennas should be used at the remote end of the link. They
confine the transmission and reception pattern to a comparatively narrow
beam, which minimizes interference to and from stations located outside the
pattern.

3. If interference is suspected from another system, it may be helpful to use
antenna polarization that is opposite to the interfering system’ s antenna s. An
additional 20 dB (or more) of attenuation to interference can be achieved by
using opposite antenna polarization.

3.2 Antenna and Feedline Selection

Antenna System

The antenna system is perhaps the most crucial part of the system design. An
antenna system that uses poor quality feedline, or is improperly aligned with the
companion site, will result in poor performance, or no communication at all.

Generally speaking, an omni-directional antenna is used at the master station
site and the remote radios use directional antennas.

GE MDS can also furnish antennas for use with the radio. Consult your GE
MDS representative for details.

Feedline Selection

For maximum performance, a good-quality feedline must be used to connect
the radio to the antenna. For short-range transmission, or where very short
lengths of cable are used (up to 8 meters [26 feet]), an inexpensive coax cable
such as Type RG-213 may be acceptable.

For example, 100 feet (30 meters) of RG-58A/U cable (commonly used for
frequencies below 100 MHz) has an insertion loss of 5 dB at 450 MHz. A 5
watt transmitter operating into such a feedline would produce only 1.6 watt at
the antenna; a similar loss in receiver sensitivity would result, and no amount
of gain within the receiver can recover the signal lost in the feedline.

Conversely, a 100 foot (30 meters) length of 1-5/8 inch cable has a loss of 0.52
dB at the same frequency, but its cost is many times greater than RG-58A/U.

For systems covering short distances, feedline loss is relatively unimportant,
and 6 dB or more of loss may be completely acceptable. For systems designed
for maximum range however, each dB of loss directly affects signal-to-noise
ratio at the receiver. It is good practice to keep feedline losses as low as
possible and certainly under 3 dB. Remember that for each 3 dB of feedline
loss, half the transmitter power is lost, and twice the receive signal power is
needed to produce the same signal-to-noise ratio.

The RG-8A/U cable is a widely available and inexpensive feedline that is
suitable for systems with short ranges or those with short feedlines. For longer

feedlines and lower losses, Andrew HELIAX
similar products are a good choice. Table 2 shows the length of various types
of cable and the resulting degradation in signal strength.

™

semi-rigid coaxial cable or

Mount the antenna and feedline securely to the supporting structure to avoid
damage from wind and ice loading. Refer to the instructions provided by the
antenna and feedline manufacturers to ensure a safe and reliable installation.

10 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Table 2. Feedline Loss Chart (450 MHz)

Cable Type

3.05 Meters
(10 Feet)

15.24 Meters
(50 Feet)

30.48 Meters
(100 Feet)

152.4 Meters
(500 Feet)

RG-8A/U 0.51 dB 2.53 dB 5.07 dB 25.35 dB
1/2 in. HELIAX 0.15 dB 0.76 dB 1.51 dB 7.55 dB
7/8 in. HELIAX 0.08 dB 0.42 dB 0.83 dB 4.15 dB
1-1/4 in. HELIAX 0.06 dB 0.31 dB 0.62 dB 3.10 dB
1-5/8 in. HELIAX 0.05 dB 0.26 dB 0.52 dB 2.60 dB

4.0 INSTALLATION PROCEDURES

This section presents the steps necessary for installing the radio and connecting
it to associated equipment. After completing these steps, the radio will be ready
for in-service operation.

4.1 Unpacking and Inspection

Figure 6 shows a typical radio shipment. Check the contents against the
packing list secured to the outside of the shipping box. Accessories and spare
parts kits, if any, are wrapped separately. Inspect all items for signs of damage.
Save all packing materials in case you need to ship the radio in the future.

Invisible place holder

POWER CORD
(AC cord shown)

ADHESIVE FEET (4)*

(For tabletop mounting)

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 11

PC DIAGNOSTICS & CONTROL
DISK (OPTIONAL)

Figure 6. Typical Shipment Contents

INSTALLATION
& OPERATION GUIDE

RACK-MOUNT BRACKETS (2)*

* These items may already be installed
on the radio chassis.

4.2 Mounting the Radio

The radio should be located in a relatively clean, dust-free environment that
allows easy access to the rear panel connectors as well as the front panel
controls and indicators. Air must be able to pass freely over the heatsink on the
rear panel.

Figure 7 shows the mounting dimensions of the radio. Most common ly, it is
installed in a 2U 3.5 inch (88.90 mm) rack-mount configuration, but it can also
be installed in a simple tabletop arrangement if desired.

Rack Mounting

To rack-mount the radio, use the supplied mounting brackets (GE MDS P/N
82-3184A01) to secure the chassis to the rack cabinet. The brackets can be
attached at any of four points on the sides of the enclosure—front, back, middle
facing front, and middle facing back (see Figure 7). This flexibility ensures
compatibility with most rack mounting arrangements.

Tabletop Mounting

As an alternative to rack mounting, the radio can be placed on any sturdy shelf
or tabletop that will support the weight of the unit. Adhesive- backed rubber
feet are provided with the radio for use in tabletop installations. These should
be placed underneath the chassis near each corner to prevent scratching of the
mounting surface.

Invisible place holder

Remote Front Panel Mounting—Optional Configuration

If desired, the front panel can be detached from the radio and mounted
separately to the rack cabinet. This option is needed in rack-mount installations
where all connections and control will be performed from one side of the unit.
An Auxiliary Mounting Plate (P/N 82-3189A01) is available for this type of
mounting.

To remove the front panel from the radio and re-mount it to the Auxiliary
Mounting Plate, follow these steps:

1. Detach the panel from the radio by grasping it firmly along its bottom edge

12 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Figure 7. Mounting Dimensions and Bracket Details

and pulling away from the radio chassis (Figure 8).

Invisible place holder

Figure 8. Front Panel Removal

2. Release the modular connector and cable from the back of the panel.

3. Plug the connector into an in-line splice connector (GE MDS P/N
73-1155A09).

4. Snap the splice connector into the front of the chassis at the square cut-out.

5. Snap the front panel onto the Auxiliary Mounting Plate in the same way it
was attached to the main radio chassis.

6. Mount the Auxiliary Mounting Plate to the rack cabinet just above (or
below) the radio chassis.

7. Attach the extension cable (GE MDS P/N 03-2198A04) between the front
panel modular connector and the in-line splice connector on the radio
chassis.

CAUTION

POSSIBLE

EQUIPMENT

DAMAGE

4.3 Primary Power

Before connecting primary power to the radio, verify that the power source
matches the power supply operating range and type of service (AC or DC).
Improper voltages may damage the equipment. The radio has either a nominal
24 Vdc, 48 Vdc, a 110/220 Vac power supply module, or 125 Vac to 12 Vdc
with external converter (see “Technical Specifications” on page 72 for voltage
ranges). The input voltage is marked on the module at the rear of the radio.

AC-Powered Units

AC-powered radios are designed to operate from 90 to 267 V ac (50-60 Hz)
primary power. No special configuration is required to operate the radio
anywhere within the input voltage range. An ac power cord is supplied with
these units. If the radio is equipped with the 110–240 V ac power supply
option, the unit can be powered from a dc source between 120 V dc to 370 V
dc as well.

DC-Powered Units

Figure 9 shows a rear view of the dc power supply. Connection to the dc power
supply is made with a three-conductor plug-in terminal strip. The radio can be
operated in either a positive or negative ground configuration. The centre pin
of the connector is not connected in the radio.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 13

Invisible place holder

Figure 9. View of Power Connector (Rear Panel)

4.4 Battery Power

A backup battery is installed in AC-powered master stations. To prevent the
battery from becoming discharged during shipment, it is left disconnected at
the factory. It must be re-connected at the time of installation to activate the
radio's battery backup feature.

The only tool required to perform this procedure is a Phillips screwdriver.

14 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Battery Connection

To connect the backup battery cable, follow these steps:

1. With no AC power applied, remove the 4 Phillips screws on each side of
the chassis and remove the top cover of the radio.

2. Connect an antenna or RF load to the radio's RF output connector. (This is
necessary because in most cases, the radio begins transmitting as soon as the
battery is connected.)

3. Locate the battery cable and plug it into the matching connector on the
Battery Control Board. (See Figure 10.)

When connecting the backup battery cable, be careful not to short the battery
charging cable or the battery “+” terminal to the radio chassis. Doing so can
cause damage to the battery and possible personal injury.

4. Reinstall the top cover, and re-apply AC power to the radio. Be sure the
power supply switch(es) are set to ON.

NOTE: If AC power is not connected, or the power switches are set to OFF,

the radio will operate on battery power until the battery becomes
discharged (approximately 1 hour). When shipping or storing the
radio, the battery cable should be disconnected.

Low Voltage Disconnect Feature

The Battery Control Board contains a Low Voltage Disconnect circuit. It prevents
damage that may be caused by having a backup battery drop below 10.65 volts
when it is powering a radio, such as during an extended AC power outage.

When the battery voltage drops to 10.65 Volts (± 0.2V), the Low Voltage
Disconnect assembly automatically disconnects the battery from the radio. This
stops operation of the radio, but protects the battery from potential damage.
When AC power returns, the battery is automatically connected to the power
supply for re-charging and normal radio operation resumes.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 15

Figure 10. Location of Backup Battery Cable

Battery Reset Switch (SW1)

Normally, the operation of the Low Voltage Disconnect assembly is fully
automatic. The only exception is when replacing a discharged battery with a
charged battery if AC power has not returned. In this case, it is necessary to
press the battery reset switch,
installing the new battery. (See Figure 11.) Use a pen or other pointed object
to press the switch.

Figure 11. Location of Battery Reset Switch

SW1 on the Battery Control Board, after

4.5 Antenna System

Antenna Installation

The antenna manufacturer’s installation instructions should be followed for
proper operation of the antenna. Using the proper mounting hardware and
bracket ensures a secure mounting arrangement with no pattern distortion or
detuning of the antenna.

Regardless of the antenna make, mount the antenna in the clear, as far away as
possible from obstructions such as buildings, metal objects and dense foliage.
Choose a location that provides a clear path in the direction of the associated
station.

NOTE: Strong fields near the antenna can interfere with the operation of

low-level circuits and change the values of the data being received.
For this reason, the antenna should be mounted at least 3 meters (10
feet) from the radio and other electronic equipment.

Feedline Installation

A low-loss feedline is recommended for use with the radio. Section 3.2,
Antenna and Feedline Selection, beginning on page 10 provides suggestions
for choosing the correct feedline for your installation. Whatever cable is used,
it should be kept as short as possible to keep signal losses to a minimum.

When installing the feedline, take care not to kink, twist or stretch the cable.
After installation, fasten the cable securely to the antenna tower or other
supporting structure.

16 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

A Type N connector is required to connect the feedline to the radio. The

Power Supply

1

13

feedline connectors must be installed in accordance with the manufacturer’s
instructions. Follow the manufacturer’s recommendations for weatherproofing
connectors that will be installed outdoors.

If large-diameter, semi-rigid coaxial cable is used for the feedline, insert a

TM

short length of 1/4 inch Superflex

Cable (GE MDS P/N 97-1677A28) or
other low-loss flexible cable between the radio and the feedline. This flexible
interface eliminates tight bends in the feedline and reduces stresses on the
feedline and connectors. The flexible section also allows the radio to be
mounted on slides and pulled out without placing undue stress on the
transmission line.

4.6 Interface Wiring Connections

All connections to the radio are made at the rear panel (Figure 12). In addition
to the power and antenna connections already discussed, there are three
interface connectors: J1–Diagnostic Port, J2–Alarm, and J3–Data.

Invisible place holder

POWER
ON/OFF

J1

POWER

INPUT

OPTIONAL POWER SUPPLY

DIAGNOSTICS

(DB-9)

(Redundant Models)

ANTENNA DATA

J9

RJ-11

ORDERWIRE

(DB-25)

J2

4-WIRE AUDIO

EXT. DUPLEXER
(OPTIONAL)

J10 ALARM

ADDITIONAL HEATSINK

(Redundant Models)

HEATSINK

RADIO A

RADIO B

Figure 12. Master Station Rear Panel

Data Connector

The data connector (available on the rear of the radio) is the main system data
interface and typically connects to the host computer.

Refer to Figure 13 and Table 3.

Invisible place holder

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 17

25

14

Figure 13. Data Connector

Table 3. Data Interface Pinouts

Pin Number Input/Output Pin Description

1--Shield Connection. Connects to ground (negative

supply potential) on the radio’s PC board.

2INTXD—Transmitted Data. Accepts TX data from the

connected device.

3OUTRXD—Received Data. Outputs received data to the

connected device.

4INRTS—Request-to-Send Input. Keys the transmitter

when RTS asserted.

5OUTCTS—Clear-to-Send Output. Active after the

6OUTDSR—Data Set Ready. Provides a +6 V dc DSR

7--Signal Ground. Connects to ground (negative supply

8OUTDCD—Data Carrier Detect. Goes active when the

9INNo Connection
10 OUT No Connection
11 OUT Receive Audio Monitoring Connection (used for

12 IN No Connection
13 -- No Connection
14 -- No Connection
15 OUT Do not connect—Reserved for future use.
16 -- No Connection
17 -- Do not connect—Reserved for future use.
18 IN/OUT No Connection
19 OUT 14.0 V dc Output. Provides a source of regulated

20 -- No Connection
21 OUT No Connection
22 -- No Connection
23 IN No Connection
24 -- Do not connect—Reserved for future use.
25 OUT No Connection

programmed CTS delay time has elapsed.

signal through a 2.5 kΩ resistor.

potential) at radio’s PC board.

radio detects an on-frequency signal.

diagnostics). Drives high-impedance load.

voltage at 1.5 amperes for low-power accessories.

18 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Diagnostics

.

A 9-pin, D-type port on the radio’s rear panel provides system diagnostics
information. The
diagnostics on the radio system from a connected computer. The
communication speed between the computer and radio is 9600 bps.

DIAGNOSTIC PORT is used to control and perform

Figure 14 shows the EIA-574 (9-pin EIA-232) pin functions of the

as viewed from the radio’s rear panel. Connection to J1 can be made with

PORT

DIAGNOSTIC

a DB-9 male connector, available from many electronics distributors.

Invisible place holder

PIN 5— GROUND
PIN 4— +5 Vdc
PIN 3— TXD

PIN 2— RXD
UNUSED
UNUSEDUNUSED

UNUSED

* Used when reprogramming the radio firmware with a PC

Figure 14. J1 Pin Connections

PIN 7— RTS*

Analog Orderwire

You can plug an ordinary telephone handset into the jack on the rear panel to
communicate with someone on a handset plugged into another radio. Handsets
are available from GE MDS (P/N 12-1307A01).

Normal system operation is unaffected if all you do is listen over the handset.
When you speak into the handset, transmit audio is applied to an automatic
voice-operated transmit keying (VOX) circuit, keying the transmitter. At the
same time, the VOX circuit switches off external transmit data, interrupting the
normal flow of data in the system. Transmit audio from the handset is then
applied to the transmitter. Your voice can then be heard through a handset at
the remote radio. Since any noise over the handset interrupts transmission, you
should unplug the handset when it is not being used.

Alarm Contacts and Battery Back-up Connections

J10 is a plug-in terminal strip that provides connections for optional alarm circuits.
Figure 15 shows the function of each terminal as viewed from the rear panel.

Terminals 1 and 2 provide relay contacts that close when a minor alarm is
encountered. Terminals 3 and 4 provide relay contacts that close when a major
alarm is encountered. These relay contacts may be remapped if necessary
(switched from minor to major alarm outputs, or vice versa). The
command is used to change the relay contacts from normally open (
normally closed (

NC).

The contacts are rated for 1 ampere at 60 Vac or Vdc.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 19

ASENSE

NO) to

Invisible place holder

Figure 15. Alarm Relay Connections

4-Wire Audio Connector

J2 is a plug-in terminal strip that provides connections for 4-wire audio circuits.
Figure 16 shows the function of each terminal as viewed from the rear panel.

Terminals 1 and 2 are for transmit audio input with a nominal 600 Ω
impedance. Terminals 3 and 4 provide a receive audio output with a nominal

Ω impedance. Pins 5 and 6 provide a source for an external keying source.

600
Connecting pins 5 and 6 together keys the radio.

4.7 Post Installation Checks

Before applying power to the radio, verify that:

This completes the installation of the radio. Section 5.0,

OPERATION

20 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Figure 16. 4-Wire Audio Connections

• All connections are properly wired and secure

• Input voltage matches that of the installed power supply

• Antenna heading is preset in the direction of the associated station.

START -UP AND

, describes the unit’s indicators and gives initial startup procedures.

5.0 START-UP AND OPERATION

The radio is designed for continuous, unattended operation. Under normal
conditions, the only time operator intervention is required is to power the unit
up or down, or to change an operating parameter. This section explains the use
of the radio’s indicators and provides steps for initial startup of the equipment.

5.1 Initial Startup

NOTE: The radio is normally continuously keyed, and transmits when the

power is switched on. Ensure there is a suitable load on the antenna
connector before switching the power on.

Operation of the radio can be started by simply connecting primary power to
the unit and setting the rear panel

Normal Indications

When power is first applied, the following events occur in a normally working unit:

• All indicators light briefly and a beep is emitted

• The front panel display shows the start-up screen, similar to Figure 19

•The

ACTIVE LED for the selected transceiver board lights. (In a

master station configured for redundant operation, the
also lights for the stand-by unit.)

POWER switch to ON.

STBY LED

Maximizing RSSI

Since the master station almost always uses an omni-directional antenna,
maximizing signal strength is done at the remote sites where directional
antennas are typically used. An RSSI greater than -90 dBm is desirable.

5.2 Front Panel Indicators

Refer to Figure 17 and the following text for an explanation of the front panel
indicators. The control buttons are described in Section 6.4, Configuration and
Programming using the Front Panel, beginning on page 44.

Invisible place holder

Figure 17. Front Panel Controls and Indicators

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 21

LED Indicators

The basic operation of the transceiver board(s) can be checked by viewing the
LED Indicator panel. The top row of indicators shows the status of the “A”
transceiver board; the bottom row shows the status of the “B” transceiver
board. In a non-redundant master station, transceiver board A is the only radio
installed. On a redundant radio (spare transceiver board and power supply
installed), the references given here apply equally to transceiver board A and
B.

Normally, only the green
redundant operation, one of the yellow

ACTIVE LED (and, in master stations configured for

STBY LEDs) should be lit. All other red

LEDs are alarm indicators. If lit, they indicate a potential problem in the radio
system.

Refer to Figure 18 and the text that follows for a detailed explanation of the
LED indicators.

Invisible place holder

Figure 18. LED Indicators

Table 4. Explanation of Front Panel LEDs

LED Name Color Meaning When Lit

ACTIVE
STBY

ALARM

RX ALR

TX ALR
I/O ALR

Green Transceiver board (A or B) is the selected unit.
Yellow Transceiver board (A or B) is currently in stand-by mode.

(Functional on master station configured for redundant
operation only.)

Red A major or minor alarm event has occurred; use the front

panel’s Active Radio Status screen to list current alarm
events (see page 61).

Red Difficulty receiving—may be due to an antenna problem,

receiver fault, or other condition causing no or a weak
received signal level.

Red Transmit circuitry fault.
Red A data framing or parity error has occurred over the data

port.

22 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Front Panel Display

At initial power-up, the front panel display shows the start-up screen
(Figure 19). After a period of time without any activity, the front panel display
darkens. The display can be restored by pressing any of the front panel buttons.

Invisible place holder

MDS 4790M MAS Radio

OWNERS NAME
OWNERS MESSAGE

Figure 19. Start-up Screen (Typical)

The start-up screen displays the owner’s name and message. Customers
typically use these fields to display the system name and site name. Other
screens, and the use of the control buttons, are described in Section 6.5, Screen
Descriptions, beginning on page 49.

Performing diagnostics, and reviewing or changing the radio’s operating
parameters, is normally done with a connected PC running InSite or other GE
MDS diagnostics software. If a PC is not available, the front panel display and
controls may be used. See Section 6.4, Configuration and Progra mming using
the Front Panel, beginning on page 44.

6.0 DIAGNOSTICS AND CONTROL

Configuration, control and diagnostics of the master station’s active
transceiver board is performed by connecting a Windows PC running InSite or
other GE MDS diagnostics software to a diagnostic port on the rear panel of
the unit (Figure 20). (If a PC is not available, many of the same functions
provided by this interface can be performed using the front panel interface,
described in Section 6.4, Configuration and Programming using the Front
Panel, beginning on page 44.)

COMPUTER

RUNNING INSITE

SOFTWARE

TO DIAGNOSTICS

CONNECTOR

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 23

TO COMPUTER'S

RS-232 CONNECTOR

Figure 20. PC Connected to the Master Station

This section explains how to connect a PC to the master station, and describes
the commands that can be used for programming and diagnostics.

6.1 PC Connection

1. Connect a DB-9 to DB-9 cable (Figure 21) between the PC and the radio’s
rear panel

2. Install a terminal emulation program, such as HyperTerminal, or InSite
Radio System Management Software (GE MDS P/N 03-3475A01), if such a
program is not already installed.

3. Launch the terminal program or diagnostics software.

DIAGNOSTIC PORT (Figure 20).

DB-9 MALE
CONNECTOR
TO RADIO

DB-9 FEMALE
CONNECTOR
TO PC

Figure 21. PC Diagnostic Port Cable (DB-9 to DB-9)

If you are using InSite, follow the instructions in the manual, InSite Radio
System Management Software Installation and Operation Guide.

If you are using a terminal emulation program:

1. Press the Space or Esc key several times, at one-second intervals, until the
> prompt is displayed, indicating that the command interface is ready to
accept input. See Tables 5 through 7 beginning on page 25 for a list of
commands.

2. Type the command, then press the

ENTER

key.

Command input is case-independent.
Use the Backspace key to delete characters.

The system displays one or more lines in confirmation. These responses are
listed in Tables 5 through 7 beginning on page 25.

You may leave the diagnostics software and PC running, or you may exit from
the diagnostics software, power down the PC, and disconnect the PC from the
radio.

6.2 PC Command Summaries

GE MDS radios are pre-configured with operating parameters that enable them
to operate in almost all situations. Should you need to adjust your radio, either
for a specific situation or to resolve a problem, this section describes
commands for changing radio operating parameters.

Tables 5 through 7 summarize master station commands.

24 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

• Table 5 (page 25) summarizes commands for setting radio operating
parameters and displaying status and other information.

• Table 6 (page 27) summarizes diagnostic and testing commands.

• Table 7 (page 28) summarizes commands for obtaining information
about the unit.

See Section 6.3, Detailed Command Descriptions, beginning on page 28 for
more information about these commands.

Commands and Command Parameters

Most commands can be used in two ways. Typing only the command:

RADIO

displays the currently programmed information. Typing the command,
followed by a space and a parameter:

RADIO B

changes a radio setting. Parameters and their meanings are listed in the
summary tables as well as the detailed command descriptions.

The following conventions are used in the table:

• Command parameters, if any, are shown in brackets [ ] following the
command name.

• A string of lower-case “x”s in a command parameter stands for a letter
or number key.

• “xxx.xxxxx” stands for a decimal number. (The decimal point
position may vary.)

• “mm,” “dd,” and “yyyy” stand for month, day and year, respectively.
(The number of characters used for month and year may vary.)

• “hh,” “mm,” and “ss” stand for hours, minutes and seconds,
respectively.

PC COMMAND

AMASK [0000
0000–FFFF FFFF]

Details, page 30

ASENSE [HI/LO]

Details, page 31

BAUD [xxxxx abc]

Details, page 31

BUFF [ON/OFF]

Details, page 31

CKEY [ON/OFF]

Details, page 32

CTS [0-255]

Details, page 32

Table 5. PC Commands—Radio Operation

FRONT PANEL

MENU

Alarm Masks

Details, page 59

Baud Rate/Format

Details, page 54

Data Buffering

Details, page 57

Continuous Keying

Details, page 56

Clear To Send Delay

Details, page 55

Set or display the major alarm mask

Set or display the sense of the alarm bits

(active high or active low)

Set or display communication attributes for

data interface port

Enable or disable received data buffering

Enable or disable continuous keying

Set or display CTS delay . Setting a value of 0

keeps CTS normally asserted.

DESCRIPTION

xxxxx=Baud rate (110, 300, 1200, 2400,
4800, 9600, 19200, 38400)

a=7 or 8 data bits
b=N for none, O for odd, E for even parity
c=1 or 2 stop bits

ON=Seamless data
OFF=Fast byte throughput

ON=Continuous keying enabled
OFF=Continuous keying disabled

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 25

Table 5. PC Commands—Radio Operation (Continued)

PC COMMAND

DATAKEY [ON/OFF]

Details, page 33

DATE [mmm dd yyyy]

Details, page 33

EMP [ON/OFF]

Details, page 34

INIT

Details, page 35

MODEM [9600M,
MPT1411]

Details, page 36

NMASK [0000
0000–FFFF FFFF]

Details, page 36

PTT [0-255]

Details, page 38

RADIO [A/B/AUTO]

Details, page 38

REPEATER [ON/OFF]

Details, page 38

RXMUTE

Details, page 39

RX [xxx]

Details, page 39

RXLEVEL [–20 to +3]

Details, page 39

RXPAD [ON/OFF]

Details, page 40

RXTOT [NONE, 1-1440]

Details, page 40

SCD [0-255]

Details, page 40

TIME [hh:mm:ss]

Details, page 43

TOT [ON/OFF, 1-255]

Details, page 43

TX [xxxx]

Details, page 43

TXGAIN [ON/OFF]

Details, page 44

TXLEVEL [–20 to +3,
AUTO]

Details, page 44

FRONT PANEL

MENU

Key On Data

Details, page 57

Set Date

Details, page 60

Emphasis

Details, page 54

Modem

Details, page 54

Push to Talk Delay

Details, page 55

Radio Selection

Details, page 61

Repeater Mode

Details, page 56

RX Mute Mode

Details, page 56

Receive Frequency

Details, page 54

Receive Level [–20 to
+3]

Details, page 58

Receive Pad

Details, page 58

RX Timeout [NONE,
1-1440]

Details, page 56

Transmit Timeout

Details, page 55

Set Time

Details, page 60

Transmit Timeout

Details, page 55,

Transmit Timeout Dura­tion

Details, page 55

Transmit Frequency

Details, page 53

Transmit Gain

Details, page 58

Transmit Level [–20 to
+3, AUTO]

Details, page 58

DESCRIPTION

Toggle between key-on-data and key-on-RTS

ON=Key-on data
OFF=Key-on RTS

Set or display the current date

Enable or disable pre-emphasis and

de-emphasis

Set all operating parameters to default settings

Set or display the radio’s modem type, or spec-

ify analog input

Set or display the minor alarm mask

Set or display PTT delay

Set or display the active transceiver board

Enable or disable repeater mode

Set or display RX (receive) Muting status

Set or display receive frequency

Set or display the analog audio receive level in

dBm

Enable or disable RX pad

Set or display the receiver timeout timer.

Set or display the soft carrier dekey delay

Set or display the current time

Set or display the timeout timer delay

Set or display the transmit frequency

Enable or disable TX gain

Set or display the analog audio transmit level in

dBm

26 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

PC COMMAND

ALARM

Details, page 28

DKEY

Details, page 33

DLINK [ON/OFF/xxxx]

Details, page 33

DMGAP [xx]

Details, page 34

DTYPE

[NODE/ROOT/GATE/PE
ER]

Details, page 34

KEY

Details, page 35

LOG [CLR]

Details, page 36

PROG

Details, page 37

PROGACT

Details, page 37

RSSI, RSSI!

Details, page 38

RTU [ON/OFF/0-80]

Details, page 39

SHOW [DC/PWR/CUR-

RENT/RADIO]

Details, page 40

SNR, SNR!

Details, page 41

STAT

Details, page 41

TEMP

Details, page 42

Table 6. PC Commands—Diagnostics

FRONT P ANEL

MENU

Active Radio Status

Details, page 61

Manual Key

Details, page 56

Manual Key

Details, page 56

Event Log

Details, page 62,

Clear Logs

Details, page 62

Receive Signal
Strength

Details, page 61

S/N Ratio

Details, page 61

Active Radio Status

Details, page 61

Show Temperature
and Voltages

Details, page 62

Display current alarm status in hexadecimal
format

Disable the transmitter

Enable or disable network-wide diagnostics
and set the baud rate at the RJ-11 DIAG port.

Set the amount of time to wait after the receipt
of a character before interpreting the next
received character as the start of a new mes­sage.

Set up a radio as a root, node, gate, or peer
radio.

Enable the transmitter

Display or clear the event log

Initiate reprogramming of the radio’s internal
software

Initiate reprogramming of the active radio

Display received signal strength indication

Enable or disable the radio’s internal RTU sim­ulator for diagnostics, and set the internal R TU
address

Display various readings:

SHOW DC DC IN xx.x V

SHOW PWR RF POWER xx DBM
SHOW CURRENT LNA xxx mA

SHOW RADIO RADIO A is active

Display signal-to-noise ratio (from DSP’s chan­nel equalizer)

Display current alarm event descriptions

Display the internal radio temperature

DESCRIPTION

DC OUT x.x V

TOTAL xxx mA

RADIO B is not
equipped

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 27

PC COMMAND

Table 7. PC Commands—

Owner and Radio Information

FRONT PANEL

MENU

DESCRIPTION

Data Buffering
screen, page 57

This graphic points you to the
corresponding front panel
menu

DUMP

Details, page 34

OPT

Details, page 37

OWM [xxxxx]

Details, page 37

OWN [xxxxx]

Details, page 37

HREV

Details, page 35

MODEL

Details, page 36

SER

Details, page 40

SREV

Details, page 41

UNIT [10000–65000]

Details, page 44

Set Owner Message

Details, page 60

Set Owner Name

Details, page 59

Serial Number

Details, page 62

Software Revision

Details, page 62

Unit Address

Details, page 57

Display all settings

Display a list of available options and the cur-

rent status of each:

Diagnostics: OFF
Premium Options: OFF
Digital Modem: OFF

Set or display an owner message or the system

name

Set or display the owner name or site name

Display the hardware revision number

Display the radio’s model number (includes

TX/RX band characteristics)

Display the radio’s serial number

Display software revision information

Display the radio’s unit address

6.3 Detailed Command Descriptions

This section gives more detailed information for most of the commands listed
in the previous tables. The commands are cross-referenced to descriptions of
corresponding commands entered using the front panel display and con trol
buttons using the graphic at left.

Most commands can be used in two ways. Typing only the command:

RADIO

displays the current information. Typing the command, followed by a space
and a parameter:

RADIO B

changes a radio setting. Parameters and their meanings are provided in the
detailed command descriptions.

ALARM

The ALARM and STAT commands report on current alarms. ALARM provides
alarm information in concise, two-line format; alarm codes are summarized in
hexadecimal format.
describing each alarm.

28 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Active Radio Status screen,
page 61

STAT (described on page 41) includes a text message

The first line of the response to the ALARM command is a simple message
indicating whether or not alarms are present. The second line is a hexadecimal
numeric code representing the system alarm state. Examples of responses are:

NO ALARMS PRESENT
CODE: 0000 0000

MINOR ALARMS PRESENT
CODE: xxxx xxxx

MAJOR ALARMS PRESENT
CODE: xxxx xxxx

Each bit of the hexadecimal response code represents a unique alarm event.
The first 4-digit number indicates major alarm conditions; if there are no major
alarms, this number is 0000. The second 4-digit number represents minor
alarm conditions; if there are no minor alarms, this number is 0000.

Code values for individual major alarm conditions are given below:

Table 8. Hexadecimal Values for Major

Alarm Conditions

Alarm Code

4000 0000 1 The hardware configuration disagrees with the software.
2000 0000 2 Model number is not programmed.
1000 0000 3 Authorization fault (radio op tion not available).
0800 0000 4 One or both of the programmable synthesizers is reporting

0200 0000 6 A/D fault
0100 0000 7 One or more of the radio’s interna l voltage regulators is

0080 0000 8 The system has not been calibrated. Factory calibration is

0020 0000 10 The radio was unable to properly program itself to the

0008 0000 12 The receiver timed out.
0004 0000 13 The transmitter timed out.
0001 0000 15 Output power fault.

Event

Number

Description

an “out of lock” condition.

reporting a failure. The radio will not work.

required for proper operation of the system.

appropriate defaults. There may be a hardware problem.

Code values for individual minor alarm conditions are given below:

Table 9. Hexadecimal Values for Minor Alarm Conditions

Alarm Code

0000 8000 16 The unit address has not been programmed.
0000 4000 17 A data parity fault has been detected on the DB25. This

0000 2000 18 A data framing error has been detected on the DB25. This

0000 0800 20 Configuration error. The modem setting is incorrect.

Event

Number

Description

usually means there is a parity setting mismatch between
the radio and the RTU.

sometimes means there is a baud rate mismatch between
the radio and the RTU.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 29

Table 9. Hexadecimal Values for Minor Alarm Conditions (Continued)

Alarm Code

0000 0040 25 The 10 volt power regulator output is out of tolerance. If

0000 0020 26 The dc input supply voltage is out of tolerance. If the

0000 0010 27 LNA current fault. (LNA current is out of range.)
0000 0008 28 Total board current fault. (Total board current is out of

0000 0001 31 The radio’s internal temperature is approaching an

Event

Number

Description

the voltage is too far out of tolerance, the radio may not
work.

supply voltage is too far out of tolerance, the radio may not
work.

range.)

out-of-tolerance condition. If the temperature drifts outside
of the recommended operating range, the radio may not
work.

AMASK [0000 0000–FFFF FFFF]

Alarm Masks screen, page 59

Table 8 and Table 9 listed the major and minor alarm classifications. It is
possible to reassign alarm outputs (illustrated in Figure 14 on page 19) to a
different category, and change which alarm events trigger an automatic
switchover in redundant master stations. However, this should be done rarely,
if ever.

AMASK command and NMASK command (page 36) command reclassify

The
major and minor alarm events, respectively, changing the alarm output relay
status and switchover conditions. These commands can be used to tailor a
radio’s alarm response. For example, a major alarm at a redundant master
station causes switch-over to the other transceiver board. By reconfiguring a
minor alarm as a major alarm, switch-over can be forced at the occurrence of
a (formerly) minor alarm condition.

Reclassifying alarms does not disable alarm notification. The front panel

ALARM LED illuminate, the alarm event is logged, and the ALARM and STAT

commands show the alarm status.
Entering the

alarm events in hexadecimal format. Entering the
by an eight-digit hexadecimal number reassigns each of the 32 possible alarm
events as enabled or disabled, with respect to major alarm output relay status
and switchover criteria.

The hex value for the mask corresponds to the hex value for the
command (see the
identifies the associated alarm event as a major alarm. Each bit that is a ‘0’
means that the alarm condition will not cause an alarm output relay to be
asserted, and will not cause a radio to switch over.

AMASK command alone displays the current setting of major

AMASK command followed

ALARM

ALARM command description). Each bit that is a ‘1’

For more information on configuring the alarm response, contact th e GE MDS
Technical Services group and request the AMASK application bulletin.

30 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

ASENSE [HI/LO]

The ASENSE command displays or sets the logic characteristics of the alarm
outputs at the

ALARM RELAY connector (see “Alarm Contacts and Battery

Back-up Connections” on page 19).
Entering the

high or low. Entering the

ASENSE command alone shows whether the alarm output is active

ASENSE command followed by HI or LO resets the

alarm output to normally closed or normally open:

ASENSE HI Normally closed
ASENSE LO Normally open

The default for a radio with a single transceiver board is normally closed

ASENSE HI).

(

BAUD [xxxxx abc]

Baud Rate/Format screen,
page 54

The BAUD command displays or sets the communication attributes for the

DATA INTERFACE port. (The command has no effect on the RJ-11
DIAG(NOSTICS) port.)

Entering the
asynchronous data attributes. Entering the

BAUD command alone displays the baud rate along with

BAUD command followed by one or

more parameters:

BAUD xxxxx abc

Example: 4800 8N1

resets the data port attributes. The first parameter, xxxxx, is baud rate. Baud rate
is specified in bits-per-second, and must be one of the following speeds: 110,
300, 1200, 2400, 4800, 9600, 19200, or 38400. In the worst case, the radio will
always accept a minimum of 500 data bytes in a single continuous data
transmission. At baud rates of 9600 bps or less, the radio can support unlimited
continuous data transmission.

The second parameter of the

BAUD command is a 3-character block specifying

asynchronous data attributes:

a = Data bits (7 or 8)
b = Parity (N for None, O for Odd, E for Even)
c = Stop bits (1 or 2)

The factory default setting is 9600 baud, 8 data bits, no parity, 1 stop bit.

NOTE: 7N1, 8O2, and 8E2 are invalid communication settings.

BUFF [ON/OFF]

Data Buffering screen, page 57

This command displays or sets the received data handling mode. Entering the

BUFF command alone shows whether the mode is seamless (ON), or fast byte

throughput (OFF). Entering the BUFF command followed by a parameter resets
the received data handling mode. The
data mode. The

OFF parameter sets the radio to fast byte throughput mode. The

default is seamless data mode.

ON parameter sets the radio to seamless

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 31

The setting of this parameter affects the timing of received data sent out the

DATA INTERFACE connector. Data transmitted over the air by the radio is

unaffected by the

BUFF setting.

If data buffering is set to
average latency. Data bytes are sent out the

OFF, the radio will operate with the lowest possible

DA TA INTERFACE port as soon as

an incoming RF data frame is disassembled. Average and typical latency will
both be below 10 ms, but idle character gaps may be introduced into the
outgoing data flow.

If data buffering is

ON, the radio will operate in a seamless mode. That is, data

bytes will be sent over the air as quickly as possible, but the receiver will buffer
the data until enough bytes have arrived to cover worst case gaps in
transmission. A 2 ms delay may be introduced by data buffering, but the radio
will not create any gaps in the output data stream. This mode of operation is
required for protocols such as MODBUS™ that do not allow gaps in their data
transmission.

Note that seamless mode (

BUFF ON) is intended only for applications where the

transmitter’s baud rate is greater than or equal to the receiver’s baud rate.
Enforcement of this rule is left up to the user.

CKEY [ON/OFF]

Continuous Keying screen,
page 56

The CKEY command enables or disables continuous keying. When CKEY is
enabled (ON), the radio is continuously keyed. The CKEY command is normally
enabled when the radio is in a full-duplex master configuration.

CTS [0-255]

Clear To Send Delay screen,
page 55

This command displays or sets the timer value associated with the CTS line
response. Entering the

CTS (Clear-to-Send) command without a parameter

displays the timer value in milliseconds. Entering the CTS command with a
parameter ranging from 0 to 255 sets the timer value in milliseconds. The timer
value function depends on the radio’s operating mode (DCE or CTS Key). See

DEVICE command for more information about these operating modes.

the
When the radio is in DCE mode, the timer specifies how long to wait after the

RTS line goes high before asserting the CTS line. A timer value of zero means
that the CTS line will go high immediately following RTS.

When the radio is in CTS Key mode, the timer specifies how long to wait after
asserting the CTS before sending data out the

DA T A INTERF ACE port. A timer

value of zero means that data will be sent out the data port without imposing a
keying delay. (Other delays may be present, depending on how other operating
parameters are configured.)

Should you experience problems with repeater operation after changing the

CTS, PTT or SCD values, contact GE MDS.

32 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

DATAKEY [ON/OFF]

Key On Data screen, page 57

This command displays or sets the keying mode. In key-on-data mode, the
radio will automatically key itself whenever input data arrives on the DB25
port. In key-on-RTS mode, the radio will only key in response to an RTS or
PTT signal (or the

KEY command).

Entering the

DATAKEY command alone shows whether the keying mode is

key-on-data (ON) or key-on-RTS (OFF). Entering the DATAKEY command
followed by a parameter controls whether or not the radio will automatically
key on receipt of data. The

ON parameter sets the radio to key-on-data mode.

The OFF parameter sets the radio to key-on-RTS mode. The default mode is
key-on-data.

Note that key-on-data mode is only applicable when the input data source is
digital. When the input data source is analog, the

DATAKEY setting is irrelevant.

DATE [mmm dd yyyy]

Set Date screen, page 60

This command sets or displays the date. The accuracy of the date and time are
important, because event codes are “stamped” with the date and time.(See also
“TIME [hh:mm:ss]” on page 43.)

Enter the command without any parameters to display the date. Enter the
command in any of the following formats to reset the date:

DATE mmm dd yyyy
DATE mm-dd-yyyy
DATE mm/dd/yyyy

where mmm is a three-character abbreviation of the month:

Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec

dd is a two-digit number from 01 to 31 representing the date, and yyyy is the
year. The radio’s calendar is fully compliant with year 2000 standards.

DKEY

Manual Key screen, page 56

This command deactivates the transmitter after it has been keyed with the KEY
command. (If other keying sources are still active, then the transmitter will not
dekey, but the manual key request is removed.)

DLINK [ON/OFF/xxxx]

This command disables or re-enables network-wide diagnostics at the local
radio, and sets the baud rate at the radio's RJ-11 DIAG port. Network-wide
diagnostics is enabled by default.

Entering
disables network-wide diagnostics.

Use the
diagnostics functionality as well as set the baud rate at the RJ-11 DIAG port.

DLINK followed by the baud rate sets the baud rate (bps) of the RJ-11 DIAG

port. The following baud rates selections are allowed:

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 33

DLINK ON enables network-wide diagnostics. Entering DLINK OFF

DLINK command locally, at the radio, to enable network-wide

•1200

•2400

•4800

•9600

• 19200 (default setting)

Example:
same baud rate must be entered into the InSite Equipment List’s

The default setting is

DLINK 4800 sets the RJ-11 DIAG port to operate at 4800 bps. The

BAUD field.

DLINK ON.

DMGAP [xx]

The DMGAP command sets the amount of time in milliseconds to wait after the
receipt of a character before interpreting the next received character as the start
of a new message. When baud rates are slow, the gap between characters
within a poll may be so long that the radio interprets the next character as the
start of a new poll. When diagnostics is being performed using passive rather
than active messaging (see “Performing Network-Wide Radio Diagnostics” on
page 65), this command may be used to prevent such errors.

DTYPE [NODE/ROOT/GATE/PEER]

This command configures a radio’s type for network-wide diagnostics. For
most radio systems, it is sufficient to define a radio as a root or node radio. The
root radio is the radio connected to the host computer for non-intrusive
diagnostics functions. Only one root can be specified per rad io network.

GATE and PEER setting are used for complex radio networks and are

The
included to accommodate network-wide diagnostics in simplex and special
radio network configurations.

Entering

ROOT configures the radio as a root radio. Entering the DTYPE command

alone displays the current setting. The default setting is

DTYPE NODE configures the radio as a node radio. Entering DTYPE

NODE.

See Section 7.2, Performing Network-Wide Radio Diagnostics, beginning on
page 65. A complete explanation of remote diagnostics can be found in GE
MDS’ Network-Wide Diagnostics System Handbook.

DUMP

The DUMP command displays programming and status information in one
quick step. Entering the

DUMP command produces the same results as entering

a series of commands that display radio information, without having to type
each command. The output format is identical to what you would see if you had
entered the individual commands one after another:

>command
command output
>command
command output
...

EMP [ON/OFF]

Emphasis screen, page 54

This command is used to enable or disable pre-emphasis and de-emphasis on
the analog input and output signals.

34 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Pre-emphasis is a function used in older analog radios where the modulating
signal is increased (at the transmitter) at the higher frequencies to increase
system performance. De-emphasis compensates (at the receiver) for a signal
that has had pre-emphasis applied.

ON indicates that pre-emphasis and de-emphasis are enabled, and OFF

indicates that pre-emphasis and de-emphasis are disabled.

HREV

This command displays the hardware revision level.

INIT

This command resets customer-programmable settings back to factory defaults:

• DCE device behavior

• 37 dBm (5 watts) RF output power

• 0ms CTS delay (that is, CTS is continuously asserted)

• 0ms PTT delay

•0ms SCD delay

• Timeout Timer (maximum continuous key duration) is enabled and
set to 30 seconds

• DB25 port set to 9600 baud, 8 data bits, no parity, 1 stop bit

• Keying mode is key-on-data

• Diagnostic test outputs are disabled

• Transmit Audio Level is set to

• Receive Audio Level is set to –10 dBm

• Repeater Mode is disabled

• Pre/de-emphasis control is disabled

• Receive Timeout Timer is disabled

• TX Gain and RX Pad are disabled

• Major Alarm Mask is set to 0xFFFF 0000

• Minor Alarm Mask is set to 0x0000 FFFF

• Alarm sense is set to ACTIVE HI

• Vox timeout time is set to 500ms

• Remote maintenance eepot settings are reset

• Continuous Key is disabled (

• Seamless operation is enabled (

DLINK is set to 19200 baud and disabled

•

•

DMGAP is set to 3

• RTU simulator is set to 0 (disabled)

• Front panel display and brightness are both set to mid-level

AUTO

CKEY)

BUFF)

KEY

This command activates the transmitter. See also the DKEY command.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 35

Manual Key screen, page 56

LOG [CLR]

Event Log screen, page 62

Clear Logs screen, page 62

This command displays or clears a list of the last 800 operating changes, called
“system events.” These events include alarm notifications, as well as normal
operator actions such as turning the power on or off. In many cases, the events
leading up to a failure can be reviewed to help determine the cause of a
problem.

Entering the

LOG command without any parameters displays the entire event

history. Entering LOG CLR or LOG CL EAR clears all current events from the log
history.

MODEL

This command displays the radio’s model number. Information about the
radio’s configuration and operating parameters can be obtained from this
number; see Section 2.6, Model Number Codes, beginning on page 6.

MODEM [9600M, MPT1411]

Modem screen, page 54

This command selects the radio’s modem characteristics. Enter 9600M for
digital operation supporting 9600 bps operation in compliance with the UK
MPT 1411 radio standard.

Enter MPT1411 for analog operation with an external modem compliant with
the United Kingdom’s MPT 1411 radio standard. (NONE is an alias for
MPT1411.)

The default selection for this command is MODEM 9600M.

NMASK [0000 0000–FFFF FFFF]

Alarm Masks screen, page 59

Table 8 and Table 9 listed the major and minor alarm classifications. It is
possible to reassign alarm outputs (illustrated in Figure 14 on page 19) to a
different category, and change which alarm events trigger an automatic
switchover in redundant master stations. However, this should be done rarely,
if ever.

AMASK command (page 30) and NMASK command reclassify major and

The
minor alarm events, respectively, changing the alarm output relay status and
switchover conditions. These commands can be used to tailor a radio’s alarm
response. For example, a major alarm at a redundant master station causes
switch-over to the other transceiver board. By reconfiguring a minor alarm as
a major alarm, switch-over can be forced at the occurrence of a (formerly)
minor alarm condition.

Reclassifying alarms does not disable alarm notification. The front panel

ALARM LED illuminate, the alarm event is logged, and the ALARM and STAT

commands show the alarm status.

36 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Entering the NMASK command alone displays the current setting of minor
alarm events in hexadecimal format. Entering the

NMASK command followed

by an eight-digit hexadecimal number reassigns each of the 32 possible alarm
events as enabled or disabled, with respect to minor alarm output relay status
and switchover criteria.

The hex value for the mask corresponds to the hex value for the
command (see the

ALARM command description). Each bit that is a ‘1’

ALARM

identifies the associated alarm event as a major alarm. Each bit that is a ‘0’
means that the alarm condition will not cause an alarm output relay to be
asserted, and will not cause a radio to switch over.

For more information on configuring the alarm response, contact GE MDS and
request Application Bulletin 98-002.

OPT

The OPT command lists each upgradable option and shows whether it is
installed (

The output format is as follows (note that

ON) or not installed (OFF).

OFF represents the current setting;

this value could be either ON or OFF):

Diagnostics : OFF
Premium Options: OFF
Digital Modem : OFF

OWM [xxxxx]

Set Owner Message screen,
page 60

The OWM command allows for display or entry of an optional text message
such as the system name. The entry can contain up to 30 characters.

OWN [xxxxx]

Set Owner Name screen,
page 59

The OWN command allows for display or entry of an optional text message
such as the site name. The entry can contain up to 30 characters.

PROG

This command reprograms the radio’s operating software. On redundant
master stations, this command reprograms the standby unit; the active unit
must then be programmed using

PROGACT (described below), or by making

the active unit the standby unit and then reprogramming it. (It can then be
switched back to standby operation, or left as the active radio.)
Reprogramming instructions can be found in the on-line help included in GE
MDS’ Radio Configuration Software (P/N 03-3156A01).

PROGACT

On redundant master stations, this command can be used to force the active
radio to be programmed. Normally, if reprogramming is required, the standby
radio is programmed while the active radio maintains normal system operation

PROG above).

(see

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 37

PTT [0-255]

Push to Talk Delay
screen, page 55

This command sets or displays the amount of time to wait after the radio
receives a keying signal from either the PTT or RTS lines before actually
keying the transmitter. Entering the

PTT (Push-to-Talk) command without a

parameter displays the timer value associated with the keying delay selection.
Entering the

PTT command with a parameter ranging from 0 to 255 sets the

timer value in milliseconds. A timer value of zero means that the radio will key
immediately following the keying signal.

The command is applicable for DCE op eration, when the radio is keyed either
by the PTT signal or by RTS. The command is not applicable when the radio

is keyed by the

KEY command.

Should you experience problems with repeater operation after changing the

CTS, PTT or SCD values, contact GE MDS.

RADIO [A/B/AUTO]

Radio Selection screen, page 61

This command sets or displays the active transceiver board, or enables
automatic switchover in the event of an alarm condition.

NOTE: Setting the active transceiver board to A or B disables automatic

switchover in the event of an alarm.

Entering the RADIO command without a parameter shows the equipped
active/inactive status for both the A and B radios.

Example: >

RADIO

Radio response:RADIO A

RADIO A IS ACTIVE
RADIO B IS INACTIVE

Entering the RADIO command with a parameter of A or B forces the active
transceiver board to the A or B transceiver board, and disables standby
redundancy.

Entering the

RADIO command with the parameter AUTO enables standby

redundancy.

REPEATER [ON/OFF]

Repeater Mode screen, page 56

This command sets or displays whether the radio is configured as a repeater.
Entering the REPEATER command without a parameter displays the current
setting (
followed by

ON=repeater; OFF=not a repeater). Entering the REPEATER command

ON enables radio operation as a repeater; OFF disables operation

as a repeater.

RSSI, RSSI!

Receive Signal Strength screen,
page 61

These commands display the Received Signal Strength Indication in dBm
units. The output can range from –50 dBm to –120 dBm.

38 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

RSSI is a “raw” signal level indicator, continuously updated in real time at

,

about a 1 second interval. The RSSI command causes the diagnostic port to
enter an RSSI update mode. The diagnostic port will display an updated RSSI
output line at roughly a 2 second interval refresh rate. The diagnostic port will
stay in this mode until you press the Enter key at the PC.

The RSSI! command provides a one-time reading and display of RSSI at the
diagnostic port.

RTU [ON/OFF/0-80]

This command enables or disables the radio’s internal RTU simulator, which
runs with GE MDS’ proprietary diagnostics software. The internal RTU
simulator is an optional feature which may or may not be available on a
particular radio; use the
(internal RTU simulator was purchased for the radio) or

OPT command to see whether DIAGNOSTICS is ON

OFF (not available on

this radio).
This command can also be used to set the RTU’s address. The internal RTU is

used for testing system payload data and pseudo bit error rate testing. It can be
helpful in isolating a problem to either the external RTU or a transceiver board.

RX [xxx]

Receive Frequency screen,
page 54

This command displays or changes the radio’s receive frequency. Normally,
the radio will be shipped to the customer programmed with the
customer-specified frequency. If the operating frequency was not specified
when the radio was ordered, the RX frequency is set to the centre of the radio’s
operating band (see Section 2.6, Model Number Codes, beginning on page 6
for the model’s operating band).

If the operating frequency is changed more than 5 MHz from the factory
setting, the helical filters must be re-tuned. If the radio is equipped with a
duplexer, and the frequency is changed more than 100 kHz, the duplexer must
be re-tuned or replaced.

RXMUTE

RX Mute Mode screen, page 54

This screen is used to set or display the radio’s RX (receive) Muting status. RX
muting may be required when the radio is configured as a full-duplex remote
and is communicating through a repeater station. RX muting prevents the radio
from hearing its own transmissions, which can cause errors in some software
applications.

Entering the
muting feature is
command followed by

RXMUTE command without a parameter shows whether the

ON (enabled) or OFF (disabled). Entering the RXMUTE

ON enables muting; entering OFF disables it.

RXLEVEL [–20 to +3]

Receive Level [–20 to +3] screen
page 58

The RXLEVEL and TXLEVEL (page 44) commands control the audio level
settings when the radio is operating in analog mode. When used alone, the

RXLEVEL command displays the receive level in dBm. Entering the RXLEVEL

command followed by a number from

–20 to +3 resets the audio level in dBm.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 39

RXPAD [ON/OFF]

Receive Pad screen, page 58

This command enables or disables the receive attenuator for the receive audio
level. Entering the

RXPAD command without a parameter shows whether the

attenuator is ON (enabled) or OFF (disabled). Entering the RXPAD command
followed by ON enables the receive attenuator; entering OFF disables it.

RXTOT [NONE, 1-1440]

The RXTOT command selects or displays the receive timeout timer value in
minutes. This timer triggers an alarm (event 12) if data is not detected within
the specified time.

Entering the
minutes. Entering the

RXTOT command without a parameter displays the timer value in

RXTOT command with a parameter ranging from 1 to

1440 resets the timer in minutes. Entering the RXTOT command with the
parameter NONE disables the timer.

SCD [0-255]

Transmit Timeout screen,
page 55

This command sets or displays the amount of time to wait after a de-key
request before actually de-keying the radio. Entering the SCD command
without a parameter displays the timer value in milliseconds. Entering the SCD
command with a parameter ranging from 0 to 255 resets the timer in
milliseconds. The default setting is 0, which means that the radio will de-key
immediately following removal of a keying signal.

Should you experience problems with repeater operation after changing the

CTS, PTT or SCD values, contact GE MDS.

SER

Serial Number screen, page 62

This command displays the radio’s serial number as recorded at the factory.

SHOW [DC/PWR/CURRENT/RADIO]

The SHOW command discloses different types of radio information, depending
on the command parameter entered. The parameters are:

•

DC—Displays dc input/output voltages.

•

PWR—Displays the actual (measured) RF power output in dBm.

•

CURRENT—Shows the low noise amplifier and total board current.
RADIO—Shows the currently active radio (A or B).

•

40 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Command Input Response

SHOW DC DC IN xx.x V

SHOW PWR RF POWER xx dBm
SHOW CURRENT LNA xxx mA

SHOW RADIO B RA DIO IS ACTIVE

DC OUT x.x V

TOTAL xxx mA

A RADIO IS [INACTIVE|NOT EQUIPPED]

SNR, SNR!

S/N Ratio screen, page 61

These commands display the signal-to-noise ratio in dB. GE MDS’ definition
of signal-to-noise is based upon the signal level following equalization, for
valid frames only. A valid frame is defined as containing no more than one bit
error, and belonging to a packet addressed for the receiving radio. SNR is
updated and latched for each valid packet received. A filter in the DSP tempers
the effect of any sudden changes in the value.

Output ranges from 10 dB to 33 dB. A value of 10 dB represents little or no
signal. A value of 24 dB represents a very strong signal.

SNR command causes the diagnostic port to enter an SNR update mode.

The
The diagnostic port will display an updated SNR output line at roughly a 2
second interval refresh rate. The diagnostic port will stay in this mode until the
Enter key is pressed at the PC.

The

SNR! command is a “computer friendly” version of SNR. It provides a

one-time reading and display of SNR at the diagnostic port.

SREV

Software Revision screen,
page 62

SREV displays the software release number, revision and build date:

06-3321A01

1.0.0 ddmmmyyyy

STAT

Active Radio Status screen,
page 61

The STAT command provides a user-friendly, interactive way to get alarm
status. (The ALARM command (page 28) summarizes alarm codes in
hexadecimal format.)

If no alarm event conditions are active, the message
displayed. If alarms are present, they are displayed in ascending order starting
with the lowest event number:

Event: 26 (MINOR)
DC input power is not in
valid range

NO ALARMS PRESENT is

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 41

Major alarms are displayed first, then minor ones.

Sh

The command output displays the event number, major/minor status, and a
one- or two-line text message, respectively. If additional alarm events are
active, the

MORE> prompt is displayed.

• Press the Enter key to display the next alarm event

•Enter

QUIT, Q, or . (period) to return to the command prompt.

The table below gives the text message displayed by the
each associated alarm event.

Table 10. Text Messages of Alarm Event Codes

Event

Number

01 Hardware mismatch
02 Model number not programmed
03 Authorization fault
04 Synthesizer out-of-lock
06 A/D fault
07 Voltage regulator fault detected
08 Radio not calibrated
10 EEPROM write failure
12 Receiver timeout
13 Transmitter timeout
15 Output power fault
16 Unit address not programmed
17 Data parity error
18 Data framing error
20 Configuration error
25 10V regulator output not in valid range
26 DC input power is not in valid range
27 LNA current is not in valid range
28 Board current not in valid range
31 Internal temperature not in valid range

Text Message

STAT command for

TEMP

This command displays the radio’s internal temperature in degrees Centigrade.
Note that the radio is designed to operate in a range from –30 C° to +60 C°, and
may fail at temperatures outside this range. This internal reading may be higher
than the outside temperature by several degrees.

42 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

ow Temperature and

Voltages screen, page 62

TIME [hh:mm:ss]

Set Time screen, page 60

This command sets or displays the time in 24-hour format. The accuracy of the
date and time are important, because event codes are “stamped” with the date
and time. (Also see “DATE [mmm dd yyyy]” on page 33.)

Enter the command without any parameters to display the time. Enter the
command in the following format to reset the time:

TIME hh:mm:ss

where hh is a two-digit number from 00-23 representing the hour (“00” is
12:00 am; “12” is 12:00 pm, and “23” is 11:00 pm), mm is a two-digit number
from 00 to 59 representing the minute, and ss is a two-digit number from 00 to
59 representing the second.

TOT [ON/OFF, 1-255]

Transmit Timeout screen,
page 55

Transmit Timeout Duration
screen, page 55

The Transmit timeout Timer limits the time that a radio can remain
continuously keyed. If a radio remains keyed for longer than the timer
duration, the transmitter is automatically de-keyed. The radio must then see a
transition back to the de-keyed state before a new keying request is allowed.

The

TOT

command entered without a parameter displays the timer value in seconds.

To enable the timer, enter TOT ON. To disable the timer, enter TO T OFF. The
default is TOT ON.

To set the timer value, enter the

TOT command followed by a parameter

ranging from 1 to 255 (seconds). The default is 30 seconds.

TX [xxxx]

Transmit Frequency screen,
page 53

This command displays or changes the radio’s transmit frequency. Normally,
the radio will be shipped to the customer programmed with the
customer-specified frequency. If the operating frequency was not specified
when the radio was ordered, the TX frequency is set to the centre of the radio’s
operating band (see Section 2.6, Model Number Codes, beginning on page 6
for the model’s operating band).

As a convenience, Table 16 at the back of this manual lists the transmit
frequencies assigned to the UK fixed telemetry and telecontrol radio services
(at the time of publication). Users are responsible to ensure their equipment is
operating on the frequencies authorized by the station licence.

NOTE: If the radio is equipped with a duplexer, and the frequency is

changed more than 100 kHz, the duplexer must be re-tuned or
replaced. Contact the factory for assistance.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 43

TXGAIN [ON/OFF]

Transmit Gain screen, page 58

This command enables or disables the transmit audio boost for the transmit
audio level. Entering the

TXGAIN

the audio boost is ON (enabled) or
command followed by ON enables audio boost; entering

command without a parameter shows whether

OFF

(disabled). Entering t h e

OFF

disables it.

TXGAIN

TXLEVEL [–20 to +3, AUTO]

Transmit Level [–20 to +3,
AUTO] screen, page 58

The TXLEVEL and RXLEVEL (page 39) commands are used to control the audio
level settings when using the analog mode. When used alone, the
command displays the transmit level in dBm. Entering the

TXLEVEL command

TXLEVEL

followed by a number from –20 to +3 (inclusive) resets the audio level in dBm.
Entering the

TXLEVEL command followed by AUTO causes the transmit level

to be set automatically.

UNIT [10000–65000]

Unit Address screen, page 57

This command sets or displays the radio’s unit address, which uniquely
identifies a single radio within a network. It is used primarily for diagnostics.

When the radio first powers up, unit address is unprogrammed. Unit address
can range from 0...65000, but can only be manually programmed from

10000...65000. (Addresses in the 0...9999 range were assigned at the factory.)

6.4 Configuration and Programming using the
Front Panel

If a PC running GE MDS diagnostics software is not available to connect to the
radio, the front panel display and controls may be used to review and change
operating parameters and perform diagnostics. This section explains how to
use the front panel controls and screens. Cross-references to the corresponding
PC-based commands are included.

The front panel display has two modes: “safe” mode (display only), and
configuration mode. These modes are changed by defining the user access
level. When the radio is powered on, the front panel display is in safe mode.
The front panel display mode, and the brightness and contrast of the front panel
display, are the only changes that can be made to the radio in safe mode. The
front panel display reverts to safe mode after a period of time has elapsed
without a button press, whenever the radio is powered back on and whenever
a switchover occurs.

Normally, if no button activity occurs for one hour, the LCD display reverts to
a power saving mode. The only exception is the Operating Status screen. This
is a special screen, found under the Diagnostics main menu. This screen
displays key status, rssi, and SNR (if applicable). The screen does not time-out,
and is preserved during power outages and radio switchovers.

Changing the front panel display to configuration mode is described in
“Switching the Front Panel Display to Configuration Mode” on page 48.

44 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Table 11. Front Panel Display’s

“safe” mode vs. “configuration” mode

Changes to...when

Safe Mode Radio is powered on

A period of time has elapsed
without a button press

Configuration
Mode

Access level is set to “User” All parameters User

Configurable

Parameters

Display mode
(safe/configuration)

Display brightness
Display contrast

Access

Level

None

Figure 22 is an overview of the front panel screens. Each screen displays a single
piece of information or radio function. The screens are divided into configuration,
diagnostics, and event log functions. Individual screens are described in more
detail in Section 6.5,

Screen Descriptions

, beginning on page 49.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 45

RADIO START-UP

Invisible place holder

ESCAPE

MDS 4790 MAS Radio

OWNERS NAME

OWNERS MESSAGE

ESCAPE

MDS 4790 MAS Radio
≥Configuration
Diagnostics
Event Log

ENTER

ENTER

Set Access Level

Set Access Level

Transmit Frequency

457.99375

Receive Frequency

463.49375

Output Power Setting

37 dBm

Modem

9600

Baudrate/Format

9600 8N1

Emphasis

disabled

Clear to Send Delay

25 milliseconds

Push to Talk Delay

0 milliseconds

Soft Carrier De-key

0 milliseconds

User

MDS 4790 MAS Radio
≥Configuration
Diagnostics
Event Log

ESCAPE

CONFIGURATION

SCREENS (CONTINUED)

DLINK Baudrate

TO CHANGE

SETTING:

ENTER

ENTER

Data Buffering

enabled

Diagnostic Link

enabled

4800

Diagnostic Type

Root

TX Audio Level

-20 dBm

RX Audio Level

-20 dBm

Transmit Gain

disabled

MDS 4790 MAS Radio
Configuration
≥Diagnostics
Event Log

ENTER

Operating Status
TX: dekeyed
RSSI:: -60 dBm
S/N: 10 dB

Active Radio Status
no alarms present

Rx Signal Strength

-60 dBm

S/N Ratio

10 dB

Radio Selection

AUTO

Radio A is Active

Transmitter Status

dekeyed

Show Temp/Voltage

30° Celcius

14.7 Volts Input

10.1 Volts Output

Serial Number
A: 12345678
B: NOT EQUIPPED

Software Revision

06-3321A01

1.5.1 1FEB2000

MDS 4790 MAS Radio
Configuration
Diagnostics
≥Event Log

ENTER

TO CHANGE

SETTING:

ENTER

ENTER

LOG 1 OF 1

4/29/00 12:00:00

System Boot

Clear Logs

TO CHANGE

SETTING:

ENTER

ENTER

ESCAPE

Transmit Timeout

enabled

Transmit Timeout

55 Seconds

Rx Timeout

none

Repeater Mode

disabled

RX Mute Mode

disabled

Continuous Keying

disabled

Manual Key

disabled

Unit Address

6682

Key On Data

disabled

Receive Pad

disabled

Alarm Masks

Major None
Minor None

Alarm Sense is HI

Display Contrast
0 50 100

Backlight Intensity
0 50 100

Set Owner Name
OWNERS NAME

Set Owner Message
OWNERS MESSAGE

Set Time

Set Time

11:34:57 AM

12:03:51 AM

Sep 14 2000

Oct 01 1999

Set Date
11:34:57 PM
Sep 14 2000

ESCAPE

ESCAPE

Figure 22. Front Panel Screen Flowchart

46 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Programming and Control Buttons

The programming and control buttons are located at the far right side of the
front panel. They are used to navigate through the front panel screens and,
when the front panel display is in configuration mode, to make changes to radio
operating parameters. Figure 23 shows a detailed view of these controls.

Invisible place holder

ENTER

ESCAPE

Figure 23. Programming and Control Buttons

• ENTER—When the start-up screen is displayed, pressing this button

displays the Menu Directory screen. Otherwise, the ENTER button
has no effect in safe mode. Its use in radio configuration is described
in “Use of Control Buttons in Configuration Mode” on page 48.

•

ESCAPE

screen or menu directory). Its use in radio configuration is describe d in
“Use of Control Buttons in Configuration Mode” on page 48.

• Up/down arrow buttons ( )—On the start-up screen, pressing

the up or down arrow button displays the menu directory. On the
menu directory screen (Figure 24), the up and down arrow buttons
cycle a selection arrow (->) through the main menu items. On the
individual menu screens, in safe mode, pressing the up or down arrow
buttons displays the menu directory.

• Left/right arrow buttons ( )—The left and right arrow

buttons cycle the display through the selected menu’s screens.

—Displays the previous screen in the menu hierarchy (start-up

Navigating Through the Front Panel Screens

Figure 22 shows the menu hierarchy, as well as the button presses used to
display the start-up and menu directory screens. (Navigation between
individual screens is done using the right or left arrow buttons.)

Invisible place holder

MDS 4790M MAS Radio

-> Configuration
Diagnostics

Selection
arrow

Figure 24. Menu Directory Screen

Displaying the menu
directory

To display the menu directory when the start-up screen is displayed, press the

ENTER, up, or down arrow button once. The menu directory lists the three

main menus—Configuration, Diagnostics, and Event Log.

Selecting a main menu
item

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 47

Pressing the up or down arrow buttons cycles the selection arrow (->) through
the main menu items.

Event Log

Displaying the
individual menu
screens

When the selection arrow points to the desired menu, press the right or left
arrow buttons to cycle the display through the screens of that menu. Each
button press displays a new screen, until the entire menu has been traversed and
the menu directory is redisplayed.

To return to the menu directory from any menu screen, press the

ESCAPE, up

or down arrow button once. Pressing any of these buttons twice displays the
start-up screen.

Switching the Front Panel Display to Configuration Mode

As previously explained, the front panel display has two modes, “safe” mode
and configuration mode. The front panel display is normally in safe mode. To
activate configuration mode:

1. From the start-up screen, press the down arrow button to display the menu
directory.

2. On the menu directory screen, press the right arrow button to display the
Access Level screen.

3. Press the

ENTER

4. Press the down arrow button to display the other access level,

5. Press the

ENTER

button to initiate a change to radio operation.

button to save the change.

USER

.

Use of Control Buttons in Configuration Mode

In configuration mode, the control buttons have additional functions:

•

ENTER—Starts and ends a change to radio functionality (enables

arrow buttons to be used for selections instead of navigation).

ESCAPE—Cancels the current radio functionality selection before

•

the ENTER button is pressed a second time.

• Up/down arrow buttons ( )—Cycles through a display of

available choices. Pressing the

ENTER button when a particular

choice is displayed reconfigures the radio using that setting.

Making Changes to Radio Functions

1. When an individual menu screen is displayed, press the ENTER button.
The message
tells the system that the next series of arrow button presses are to make
on-screen selections, not display menu screens.

2. Most options are either words (“enabled,” “disabled”) or numbers. The
instructions below apply in most situations; if not, the method for choosing
an option is detailed in the screen description.

Word options

up or down arrow button.

Numeric options

change: press the left or right arrow button to move the underscore
cursor ( _ ) under the digit to be changed. (For example, to change “30” to

“40,” move the underscore under the “3.”) Then press the up or down
arrow buttons to increase or decrease the number. Or hold down the arrow
button to scroll choices more rapidly.

3. Press the
press the
indicating that the change was successfully made.

change pending appears at the bottom of the screen. This

. To display all choices when the options are words, press the

. If the option is more than one digit, first select the digit to

ENTER

ESCAPE

button again when the desired choice is displayed. (Or

button to cancel the change.) The message

done

appears,

48 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

TX [xxxx] command, page
43

This graphic points you
to the corresponding PC
command

6.5 Screen Descriptions

This section describes each of the front panel display screens. The commands
are cross-referenced to descriptions of corresponding commands entered from
a connected PC using the graphic at left.

These screens are presented in four major groups:

Group 1—Startup Screen and Menu Directory (page 53)

These screens are starting points for all programming and viewing activities.

Group 2—Configuration Screens (page 53)

The Configuration screens are used to view or define the radio’s operating
parameters. They include:

• Set/display access level (front panel display mode)

• Set/display transmit and receive frequency

• Set/display output power

• Set/display modem speed

• Set/display data port baud rate and parity

• Enable/disable pre-emphasis and de-emphasis

• Set/display Clear to Send (CTS) delay

• Set/display Push to Talk (PTT) delay

• Set/display soft carrier dekey delay

• Enable/disable Transmit Timeout Timer

• Set/display Transmit Timeout Timer delay

• Enable/disable RX Timeout Timer

• Enable/disable repeater mode

• Enable/disable RX Mute mode

• Enable/disable continuous keying

• Key/dekey radio manually

• Display unit address

• Set/display keying mode (key on data/key on RTS)

• Enable/disable data buffering

• DLINK on/off setting

• DLINK baud rate setting (set/display)

• Set/display DTYPE (Diagnostic radio type)

• Set/display transmit and receive audio level

• Enable/disable transmit gain and receive pad

• Display major and minor alarm masks and alarm sense

• Set/display front panel display contrast and intensity

• Set/display owner name and message

• Set/display time and date

Group 3—Diagnostic Screens (page 61)

The Diagnostic screens display important status information for the local and
remote radio, as well as run several tests useful in locating system problems.
The Diagnostic screens include:

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 49

• Display operating status information

• Display active radio status

• Display receive signal strength

•Display S/N ratio

• Set/display active transceiver board selection

• Display transmitter state (keyed, dekeyed)

• Display internal temperature and voltages

• Display radio serial number(s) for the A and B transceiver boards

• Display software revision level

Group 4—Event Log (page 62)

The event log displays up to 800 of the most recent operating changes. These
events include system problems, as well as normal operator actions such as
turning the power on or off. The screens in this group are:

• Display event log entries

• Clear event log

The following table organizes front panel screens in the same way as the PC
commands described earlier in this manual: operating parameters, diagnostics,
and radio information.

Table 12. Front Panel Screens—Operating Parameters

FRONT PANEL

SCREEN

Access Level

Details, page 53

Alarm Masks

Details, page 59

Backlight Intensity

Details, page 59

Baud Rate/Format

Details, page 54

Clear To Send Delay

Details, page 55

Continuous Keying

Details, page 56

Data Buffering

Details, page 57

Display Contrast

Details, page 59

Emphasis

Details, page 54

Key On Data

Details, page 57

Manual Key

Details, page 56

Menu Directory

Details, page 53

PC COMMAND DESCRIPTION

Enable or disable configuration mode

AMASK [0000
0000–FFFF FFFF]

Details, page 30,

NMASK [0000
0000–FFFF FFFF]

Details, page 36

ASENSE [HI/LO]

Details, page 31

BAUD [xxxxx abc]

Details, page 31

CTS [0-255]

Details, page 32

CKEY [ON/OFF]

Details, page 32

BUFF [ON/OFF]

Details, page 31

EMP [ON/OFF]

Details, page 34

DATAKEY [ON/OFF]

Details, page 33

DKEY

Details, page 33

KEY

Details, page 35

Set or display hexadecimal code identifying

whether alarm events cause an alarm output
relay to be asserted and cause the active
radio to switch over; also displays the alarm
sense

Set or display front panel display’s back-

ground brightness

Set or display data interface port communica-

tion attributes

Set or display the time to wait after RTS is

asserted by the host computer before assert­ing the CTS line

Select continuous or non-continuous keying

Enable or disable data buffering

Set or display front panel display’s foreground

character intensity

Enable or disable pre-emphasis and

de-emphasis

Set or display keying behavior (key-on-data or

key-on-RTS)

Manually key or dekey the transmitter

Select diagnostic, configuration, or event log

screens

50 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Table 12. Front Panel Screens—Operating Parameters (Continued)

FRONT PANEL

SCREEN

Modem

Details, page 54

PC COMMAND DESCRIPTION

MODEM [9600M,
MPT1411]

Details, page 36

Set or display internal modem speed

Push to Talk Delay

Details, page 55

Radio Selection

Details, page 61

Receive Frequency

Details, page 54

Receive Level [–20 to +3]

Details, page 58

Receive Pad

Details, page 58

Repeater Mode

Details, page 56

RX Timeout [NONE,
1-1440]

Details, page 56

Set Date

Details, page 60

Set Time

Details, page 60

Transmit Timeout

Details, page 55

Transmit Frequency

Details, page 53

Transmit Gain

Details, page 58

Transmit Level [–20 to
+3, AUTO]

Details, page 58

Transmit Timeout

Details, page 55

Transmit Timeout Dura­tion

Details, page 55

PTT [0-255]

Details, page 38

RADIO [A/B/AUTO]

Details, page 38

RX [xxx]

Details, page 39

RXLEVEL [–20 to +3]

Details, page 39

RXPAD [ON/OFF]

Details, page 40

REPEATER [ON/OFF]

Details, page 38

DATE [mmm dd yyyy]

Details, page 33

TIME [hh:mm:ss]

Details, page 43

SCD [0-255]

Details, page 40

TX [xxxx]

Details, page 43

TXGAIN [ON/OFF]

Details, page 44

TXLEVEL [–20 to +3,
AUTO]

Details, page 44

Set or display the amount of time to wait after

host computer asserts RTS before keying the
radio and beginning transmittal

Set or display the active transceiver board;

enable or disable automatic switch-over

Set or display the receive frequency

Set or display the radio’s audio transmit level

when the radio is operating in analog mode

Enable or disable the receive attenuator for

the receive audio level

Enable or disable repeater mode

Set or display amount of time to wait without

data receipt before generating an alarm and
switching to the stand-by transceiver board

Set or display the date

Set or display the time

Set or display amount of time to wait after a

de-key request before actually de-keying the
radio

Set or display the transmitter frequency

Enable or disable the transmit audio boost for

the transmit audio level

Set or display the radio’s audio transmit level

when the radio is in analog mode

Enable or disable the Transmit T i meout timer

(time to wait before disabling the transmitter
to prevent unnecessary use of the frequency)

Set or display the Transmit Timeout duration

(time to wait before disabling the transmitter
to prevent unnecessary use of the frequency)

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 51

Table 13. Front Panel Screens—Diagnostics

FRONT PANEL

SCREEN

Active Radio Status

Details, page 61

Clear Logs

Details, page 62

Event Log

Details, page 62

S/N Ratio

Details, page 61

Show Temperature and
Voltages

Details, page 62

Start-up Screen

Details, page 53

Transmitter Status

Details, page 62

PC COMMAND DESCRIPTION

STAT

Details, page 41

LOG [CLR]

Details, page 36

LOG [CLR]

Details, page 36

SNR, SNR!

Details, page 41

TEMP

Details, page 42

Display alarm conditions

Clear the event log

Display events logged by the active trans-

ceiver board

Display the signal-to-noise ratio in dBm

Display the radio’s internal temperature and

voltages

Display the radio name, owner name, owner

message, and any alarms

Display the transmitter state (keyed or

dekeyed)

Table 14. Front Panel Screens—Owner and Radio Information

FRONT PANEL

SCREEN

Serial Number

Details, page 62

Set Owner Message

Details, page 60

Set Owner Name

Details, page 59

Software Revision

Details, page 62

Start-up Screen

Details, page 53

Unit Address

Details, page 57

PC COMMAND DESCRIPTION

SER

Details, page 40

OWM [xxxxx]

Details, page 37

OWN [xxxxx]

Details, page 37

SREV

Details, page 41

UNIT [10000–65000]

Details, page 44

Display the active transceiver board’s serial

number (not the radio serial number)

Set or display the owner message or site

name

Set or display the owner name or system

name

Display the internal software part number and

version number

Display the radio name, owner name, owner

message, and any alarms

Displays the radio’s unit address

52 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

GROUP 1—MAIN SCREENS
Start-up Screen When the radio is first powered on, or after a period of time has elapsed after the

last button press, the front panel display shows the start-up screen. The start-up

MDS 4790M MAS Radio

OWNERS NAME
OWNERS MESSAGE

screen displays the product model number, as well as the owner’s name and
message. (Typically , customers use the owner name and message fields to display
the system and site name.)

The screen dims after a period of time has elapsed without any activity; brightness
can be restored by pressing any button.

To change what is displayed on this screen, see “Set Owner Name” on page 59
and “Set Owner Message” on page 60.

Press ENTER, or the up or down arrow button, to display the Menu Directory screen.

Menu Directory This screen is used to access three screen display cycles: Configuration,

MDS 4790M MAS Radio

->Configuration
Diagnostics
Event Log

Diagnostics, and Event Log. The selection arrow (
selected menu.

Press the up/down arrow buttons to move the arrow to the desired menu, then press
the right/left arrow buttons to display each of that menu’s screens in succession.

->) points to the currently

GROUP 2—CONFIGURATION
Access Level This screen is used to set the front panel display to configuration mode by selecting

Set Access Level

User

a level of access. There are two levels:

NONE—This is the default setting upon power-up (“safe” mode). All radio set­tings can be viewed, the access level can be changed, and the front panel dis­play brightness and contrast can be changed. All other settings are for display
only, and cannot be changed.

USER—Changes can be made to any radio parameter (“configuration” mode).

To select the USER access level, press ENTER, press the down arrow button to
display the word “User,” then press ENTER again to make the change.

The radio returns automatically to safe mode (access level:
time has elapsed without a button press, or if the radio is powered off and then on.

NONE

) after a period of

Transmit
Frequency

Transmit Frequency

400.00000 MHz

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 53

This screen is used to display or set the transmitter frequency. Normally, the radio
will be shipped to the customer programmed with the customer-specified
frequency. If the operating frequency was not specified when the radio was
ordered, the TX frequency is set to the center of the radio’s operating band. The
range of frequencies for the model are given Section 2.6, Model Number Codes,
beginning on page 6.

To change this value, press ENTER, then use the left/right arrow buttons to select
a digit. Then use the up/down arrow buttons to increase or decrease the number.
Press ENTER to make the change.

If the operating frequency is chan ged more than 5 MH z from the factory se tting, the
helical filters must be re-tuned. If the radio is equipped with a duplexer, and the
frequency is changed more than 100 kHz, the duplexer must be re-tuned or
replaced.

TX [xxxx] command, page 43

Receive
Frequency

Receive Frequency

400.00000 MHz

This screen is used to display or set the receive frequency. Normally , the radio will
be shipped to the customer programmed with the customer-specified frequency. If
the operating frequency was not specified when the radio was ordered, the RX
frequency is set to the centre of the radio’s operating band. The range of
frequencies for the model are given Section 2.6, Model Number Codes, beginning
on page 6.

To change this value, press ENTER, then use the left/right arrow buttons to select
a digit. Then use the up/down arrow buttons to increase or decrease the number.
Press ENTER to make the change.

If the operating frequency is chan ged more than 5 MH z from the factory se tting, the
helical filters must be re-tuned. If the radio is equipped with a duplexer, and the
frequency is changed more than 100 kHz, the duplexer must be re-tuned or
replaced.

RX [xxx] command, page 39

Modem This screen is used to set or display the internal modem speed for compatibility

Modem

9600M

with the modem in the central host computer.
To change the modem selection, press ENTER, then use the up/down arrow

buttons to display available selections. Press ENTER to make the change.

MODEM [9600M,
MPT1411] command,
page 36

Baud Rate/Format This screen is used to set or display the communication attributes for the DATA

INTERFACE port. For a description of the communication attributes, see BAUD
[xxxxx abc] command

To change the baud rate, press ENTER, then press the left arrow button to move
the underscore under the baud rate. Then use the up/down arrow buttons to select
a new baud rate.

T o change the data format, press ENTER, then press the right arrow button one or
more times to move the underscore (_) under the character to change. Then use
the up/down arrow buttons to change the character. Repeat for the other
characters in the data format if necessary. Press ENTER to make the change.

, page 31.

BAUD [xxxxx abc] command,
page 31

Emphasis This screen is used to enable or disable pre-emphasis and de-emphasis on the

Emphasis

enabled

analog input and output signals.
Pre-emphasis is a function used in older analog radios where the modulating signal

is increased (at the transmitter) at the higher frequencies to increase system
performance. De-emphasis compensates (at the receiver) for a signal that has had
pre-emphasis applied.

To enable or disable pre-emphasis and de-emphasis, press ENTER, then use the
up/down arrow buttons to display ENABLED or DISABLED. Press ENTER to make
the change.

EMP [ON/OFF] command,
page 34

54 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Clear To Send
Delay

Clear to Send Delay

0 milliseconds

This screen is used to set or display the Clear-to-Send Delay. This is the amount
of time to wait after RTS is asserted by the host computer on the data port before
asserting the CTS line. When the delay is 0, data will be sent out the data port
without imposing a keying delay.

To change the delay, press ENTER, then use the left/right arrow buttons to select the
digit to change. Then use the up/down arrow buttons to increase or decrease the digit.
Repeat for the other digits if necessary. Press ENTER again to make the chan ge.

CTS [0-255] command,
page 32

Push to Talk Delay This screen is used to set or display the Push to T alk Delay. This is the amount of

time to wait after RTS is asserted by the host computer before the radio is keyed

Push to Talk Delay

0 milliseconds

and begins to transmit. When the delay is 0, the radio will key up immediately
following the keying signal.

To change the delay, press ENTER, then use the left/right arrow buttons to select the
digit to change. Then use the up/down arrow buttons to increase or decrease the digit.
Repeat for the other digits if necessary. Press ENTER again to make the chan ge.

PTT [0-255] command,
page 38

Soft Carrier De-key
Delay

Soft Carrier De-key

0 milliseconds

This screen is used to set or display the Soft Carrier Dekey Delay. This is the
amount of time to wait after a de-key request before actually de-keying the radio.
When the delay is 0, the radio will de-key immediately following removal of a keying
signal.

To change the delay, press ENTER, then use the left/right arrow buttons to select the
digit to change. Then use the up/down arrow buttons to increase or decrease the digit.
Repeat for the other digits if necessary. Press ENTER again to make the chan ge.

SCD [0-255] command,
page 40

Transmit Timeout This screen is used to display the Transmit Timeout setting, and to enable or

Transmit Timeout

enabled

disable this timer. When this timer is enabled, it disables the transmitter after a set
period of time to prevent unnecessary use of the frequency. If the radio is set to
continuous keying (see “Continuous Keying” on page 56), the Transmit Timeout
Timer is automatically disabled.

To enable or disable the timer, press ENTER, then use the up/down arrow buttons
to display ENABLED or DISABLED. Press ENTER to make the change.

See the following command to change the timer delay.

Transmit Timeout
Duration

Transmit Timeout

30 seconds

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 55

TOT [ON/OFF, 1- 25 5]
command, page 43

This screen is used to set or display the Transmit Timeout duration. This is the
amount of time to wait before disabling the transmitter to prevent unnecessary use
of the frequency. If the radio is set to continuous keying (see “Continuous Keying”
on page 56), Transmit Timeout is automatically disabled.

To change the duration, press ENTER, then use the left/right arrow buttons to
select the digit to change. Then use the up/down arrow buttons to increase or
decrease the digit. Repeat for the other digit if necessary. Press ENTER again to
make the change.

TOT [ON/OFF, 1-255]
command, page 43

RX Timeout
[NONE, 1-1440]

RX Timeout

none

This screen is used to set or display the RX Timeout Timer duration. This is the
amount of time to wait (in minutes) after the last data receipt before switching over
to the stand-by transceiver board and generating an alarm.

To change the duration, press ENTER, then use the left/right arrow buttons to
select the digit to change. Then use the up/down arrow buttons to increase or
decrease the digit. Repeat for the other digit if necessary. Press ENTER again to
make the change.

To disable the Receive Timeout Timer, set the duration to NONE.

Repeater Mode This screen is used to set or display the radio’s operation as a repeater. When the

Repeater Mode

enabled

radio is set to operate as a repeater, the screen displays “enabled” (repeater mode
is enabled). When the radio is a non-repeater, the screen displays “disabled”
(repeater mode is disabled).

T o change the operating mode, press ENTER, then use the up/down arrow buttons
to select ENABLE (repeater mode) or DISABLE (non-repeater mode). Press
ENTER again to make the change.

REPEATER [ON/OFF]
command, page 38

RX Mute Mode This screen is used to set or display the radio’s RX (receive) Muting status. RX

RX Mute Mode

disabled

muting may be required when the radio is configured as a full-duplex remote and
is communicating through a repeater station. RX muting prevents the radio from
hearing its own transmissions, which can cause errors in some software
applications.

T o change the RX Mute status, press ENTER, then use the up/down arrow buttons
to select ENABLE (RX Mute on) or DISABLE (RX Mute off). Press ENTER again
to make the change.

RXMUTE command, page
39

Continuous
Keying

Continuous Keying

enabled

This screen is used to set or display the radio’s keying mode (continuous or
non-continuous keying). Typically, a master station is set for continuous keying. If
continuous keying is disabled, the radio needs to be keyed with Pin 4 (RTS) of the
interface connector.

T o change the keying mode, press ENTER, then use the up/down arrow buttons to
select ENABLE (continuous keying) or DISABLE (non-continuous keying). Press
ENTER again to make the change.

CKEY [ON/OFF] command,
page 32

Manual Key This screen is used to manually key or dekey the transmitter. The transmitter state

Manual Key

disabled

can be displayed by selecting Transmitter Status from the Diagnostics menu
(page 62).

T o key the transmitter , press ENTER, then use the up/down arrow buttons to select
ENABLE (manual keying). Press ENTER again to key the transmitter.

56 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

To dekey the transmitter, press ENTER, then use the up/down arrow buttons to

d

select DISABLE (manual dekeying). Press ENTER again to dekey the transmitter.

KEY command, page 35

DKEY command, page 33

Unit Address This screen displays the radio’s unit address, which uniquely identifies a single

Unit Address

2067

radio within a network. It is used primarily for diagnostics.
When the radio first powers up, unit address is unprogrammed. Unit address can

range from 0...65000, but can only be manually programmed from 10000...65000.
(Addresses in the 0...9999 range only occur when they are assigned as default
values following factory programming of the serial number.).

UNIT [10000–65000]
command, page 44

Key On Data This screen is used to set or display the radio’s keying mode (key-on-data, or

Key On Data

enabled

key-on-RTS). In key-on-data mode, the radio will automatically key itself whenever
input data arrives on the DB-25 port. In key-on-RTS mode, the radio will only key
in response to an RTS or PTT signal.

To set the radio to key-on-data mode, press ENTER, then use the up/down arrow
buttons to select ENABLE. Press ENTER again to make the change. To set the
radio to key-on-RTS mode, press ENTER, then use the up/down arrow buttons to
select DISABLE. Press ENTER again to make the change.

Note that key-on-data mode is only applicable when the input data source is digital.
When the input data source is analog, this setting is irrelevant.

Data Buffering

Data Buffering

enabled

DLINK Baudrate

DLINK Baudrate

4800

DATAKEY [ON/OFF] comman
page 33

This screen is used to enable or disable data buffering. If data buffering is enabled,
the radio operates in seamless mode, where the data is sent over the air as quickly
as possible. However , the receiver will buffer (hold) the data until enough byte s have
arrived to cover worst-case gaps in transmission. This mode of operation is required
for protocols such as MODBUS™ that do not allow gaps in their data transmission.

If data buffering is disabled, the radio operates with the lowest possible data
latency (average). Data bytes are sent out the data port as soon as an incoming
RF data frame is disassembled. Average and typical latency will both be below 10
ms, but idle character gaps may be introduced into the outgoing data flow.

To enable or disable data buffering, press ENTER, then use the up/down arrow
buttons to display ENABLE or DISABLE. Press ENTER again to make the change.

BUFF [ON/OFF] command,
page 31

This screen is used to set or display the diagnostic baud rate. Allowable selections
are: 1200, 2400, 4800, 9600 and 19200 bps.

To change the setting, press ENTER, then use the up/down arrow buttons to
display the desired setting. Press ENTER again to make the change.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 57

Note: This screen is associated with Network-wide Diagnostics. For more
information, refer to the Network-wide Diagnostics manual (P/N 05-3467A01)
available from GE MDS.

DLINK [ON/OFF/xxxx]
command, page 33

Diagnostic Type

Diagnostic Type

Node

Transmit Level
[–20 to +3, AUTO]

Transmit Level

-1 dBm

Receive Level [–20
to +3]

Receive Level

-1 dBm

This screen is used to set or display the radio’s function in a network-wide
diagnostics system. The allowable settings for the radio are Node, Root, Gate and
Peer.

Note: This screen is associated with Network-wide Diagnostics. For more
information, refer to the Network-wide Diagnostics manual (P/N 05-3467A01)
available from GE MDS.

DTYPE
[NODE/ROOT/GATE/PEER]

This screen is used to set or display the radio’s audio transmit level when the radio
is operating as an analog device. The audio transmit level can be set from –20 to
+3 dBm, or it can be set to adjust automatically.

To change the audio transmit level, press ENTER. You do not need to use the
left/right arrow buttons to select a digit. Instead:

To increase the transmit level, press the up or left arrow button ( ).
To decrease the transmit level, press the down or right arrow button ( ).

Press ENTER again to make the change.

TXLEVEL [–20 to +3, AUTO]
command, page 44

This screen is used to set or display the radio’s audio receive level when the radio is
operating as an analog device. The audio receive level can be set from –20 to +3 dBm.

To change the audio receive level, press ENTER. You do not need to use the
left/right arrow buttons to select a digit. Instead:

To increase the receive level, press the up or left arrow button ( ).
To decrease the receive level , press th e down or right arrow button ( ).

Press ENTER again to make the change.

RXLEVEL [–20 to +3] command
page 39

Transmit Gain This screen is used to enable or disable the transmit audio boost for the transmit

Transmit Gain

disabled

Receive Pad This screen is used to enable or disable the receive attenuator for the receive audio

Receive Pad

disabled

58 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

audio level.

TXGAIN [ON/OFF] command,
page 44

level.

RXPAD [ON/OFF] command,
page 40

Alarm Masks This screen is used to display hexadecimal codes which specify whether each

Alarm Masks
Major FFFF 0000
Minor 0000 FFFF

Alarm Sense is HI

alarm event will result in:

• an alarm output relay to be asserted and

• a radio switch-over.
The screen also displays the alarm sense setting. For an explanation, or to change

the alarm masks, see the following PC commands:

AMASK [0000 0000–FFFF
FFFF] command, page 30

ASENSE [HI/LO] command,
page 31

Display Contrast This screen is used to set the intensity of the front panel display’s foreground

Display Contrast

050100

characters. Making the characters darker may aid the clarity of the front panel
display when viewed from an angle.

The bar display indicates the relative intensity of the foreground characters, with ‘0’
being faint characters and ‘100’ being dark characters.

To change the selection, press ENTER, then use the left/right arrow buttons to
move the bar display to the desired setting. The screen changes dynamically to
show the effects of the change. Press ENTER again to set the change.

Backlight Intensity This screen is used to set the brightness of the front panel display’s background.

Making the screen background brighter or dimmer may aid the clarity of the front

Backlight Intensity

050100

panel display when viewed under different light conditions.
The bar display indicates the relative brightness of the screen background, with ‘0’

being dim and ‘100’ being very bright.
To change the selection, press ENTER, then use the left/right arrow buttons to

move the bar display to the desired setting. The screen changes dynamically to
show the effects of the change. Press ENTER again to set the change.

Set Owner Name This screen is used to set or display text (up to 20 characters) to appear on the

Set Owner Name

^
_!”#$%&’()*+,-./0123

radio’s start-up screen, such as the system name.
Press ENTER to display a scrollable line of characters at the bottom of the screen.

An underscore (_) is used to select a character for the owner name (Figure 25). A
caret (^) shows the current character position.

• Press the up arrow button to move the underscore to the left until it is
under the first character of the owner name. As you scroll to the left, the
character under the underscore appears above the caret.

• Press the right arrow button once to move the caret to th e ne xt
character position to the right.

• Press the up or down arrow buttons to move the underscore to the next
character.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 59

• Continue in this way, using the up/down arrow buttons to move the
underscore to a character, then pressing the right arrow button to move to the
next character position.

• Press ENTER to save the owner name.

OWN [xxxxx] command, page 37

Figure 25. Setting the Owner Name and Message

Set Owner
Message

Set Owner Message

Set Time

Set Time
12:04:03 AM
May 01 1999

Set Date

Set Date
12:04:03 AM
May 01 1999

This screen is used to set or display text (up to 20 characters) to appear on the
radio’s start-up screen, such as the site name. See the Set Owner Name command
and Figure 25 above for instructions.

OWM [xxxxx] command,
page 37

This screen is used to set or display the time set in the radio. The accuracy of the date
and time are important, because event codes are “stamped” with the date and time.

To change the time, press ENTER, then use the left/right arrow buttons to select
the hour, minute, second, or AM/PM. Then use the up/down arrow buttons to
increase or decrease the digit, or toggle between AM and PM. Repeat for other
characters if necessary. Press ENTER again to make the change.

TIME [hh:mm:ss] command,
page 43

This screen is used to set or display the date set in the radio. The accuracy of the date
and time are important because event codes are “stamped” with the date and time.

To change the date, press ENTER, then use the left/right arrow buttons to select
the month, day, or year. T hen use the up/down arrow buttons to increase or
decrease the day or year, or set the month. Repeat for other characters if
necessary. Press ENTER again to make the change.

DATE [mmm dd yyyy]
command, page 33

60 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

GROUP 3—DIAGNOSTICS
Operating Status This screen displays three key operating conditions of the radio; TX key status,

Operating Status
TX: dekeyed
RSSI: -60 dBm
S/N 10 dB

Active Radio
Status

Active Radio Status

Alarms present

(enter for details)

Event: 20 (MINOR)
Configuration error

Receive Signal
Strength

Rx Signal Strength

-120 dBm

Received Signal Strength Indication (RSSI), and Signal-to-Noise (S/N) ratio. Unlike
other screens, the information shown on the Operating Status screen is preserved
across power outages and radio switchovers. This screen has no timeout and will
remain displayed until changed by an operator.

This screen is used to display alarm conditions, if any. A list of major and minor
alarm events can be found in Table 10 on page 42.

If alarms are indicated, press ENTER to display the first alarm. To scroll through
the list of alarms, press the right or down arrow button. Press ESCAPE to
return to the Active Radio Status screen.

STAT command, page 41

This screen displays the received signal strength in dBm.
In a typical master station configuration, the received signal strength is read from

each of the remote radios that transmit to the master station in turn.

RSSI, RSSI! command,
page 38

S/N Ratio This screen displays the current signal-to-noise ratio in dBm.

S/N Ratio

SNR, SNR! command, page 41

Radio Selection This screen is used to set or display the active transceiver board inside the radio.

Radio Selection

AUTO

Radio A is active

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 61

When the radio selection is:
AUTO—switch-over to the inactive transceiver board will occur if a fault condition

occurs on the active transceiver board.
A—transceiver board A is set as the active transceiver board and switch-over

will not occur if an error condition is detected in the radio.
B—transceiver board B is set as the active transceiver board and switch-over

will occur if an error condition is detected in the radio.

To change which transceiver board is active, or to enable automatic switch-over,
press the ENTER key, then use the up/down arrow buttons to select AUTO, A or
B. Press ENTER again to make the change.

RADIO [A/B/AUTO]
command, page 38

Transmitter Status This screen displays the transmitter state. “Keyed” means the transmitter is set to

Transmitter Status

keyed

transmit; “dekeyed” means the transmitter is prevented from transmitting. The
transmitter can be keyed or dekeyed by selecting Manual Key from the
Configuration menu (page 56). This setting is used when working on the radio,
and the radio must be keyed to evaluate transmitter output power.

Show Temperature
and Voltages

Show Temp/Voltage

37° Celsius

11.2 Volts Input

5.8 Volts Output

This screen displays the radio’s internal temperature and voltages. The input
voltage is the voltage that connects to the transceiver board and is unregulated.
This voltage is essentially the output from the power supply assembly. The output
voltage is read after a 10 V dc regulator on the transceiver board.

TEMP command, page 42

Serial Number This screen displays the serial numbers of the transceiver boards. These numbers

Serial Number

A: 00755959
B: 00816359

will not match the serial number on the serial number label on the radio. If the radio
is not equipped with a second transceiver board, one of the lines will read “NOT
EQUIPPED.”

SER command, page 40

Software Revision This screen displays the internal software part number and version number.

Software Revision

06-3321A02

0.0.0 5Aug1998

SREV command, page 41

GROUP 4—EVENT LOG
Event Log This screen shows the events logged on the active transceiver board. In many

Log 1 of 1

5/ 1/1998 12:00;00

System Boot

cases, the events leading up to a failure can be reviewed to help determine the
cause of a problem. The event log number, date and time of the event, and a
description of the event are shown.

This screen shows the most recent log when first entered. Use the up/down arrow
buttons to scroll through the stored history of events.

LOG [CLR] command, page 36

Clear Logs This screen is used to erase all events from the event log.

Clear Logs

Are you sure?

No

(change pending)

62 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

LOG [CLR] command, page 36

7.0 LOCAL & NETWORK-WIDE
PROBLEM SOLVING

The majority of radio operation problems are due to the failure of components
outside of the radio, out in the elements—usually a poor or broken feedline or
antenna connection. This section will help you determine whether the problem
is outside or inside the radio; and, if in the radio, how to restore operation as
quickly as possible.

GE MDS does not recommend component-level repairs in the field. However,
the radio’s major assemblies may be replaced without using tools or test
equipment. Section 7.3, Replacing Assemblies, beginning on page 67 covers
this in detail.

If you are unable to solve a system problem with the information provided
here, technical assistance is also available from GE MDS. Refer to the inside
back cover of this guide for contact information.

NOTE: Before starting any detailed troubleshooting, check the basic

requirements at both ends of the link: primary power, secure cable
connections, and proper antenna heading. In many cases, one of
these things may be at fault and cause poor operation or a complete
loss of link service.

7.1 Local Problem-Solving

Problem-Solving with LED Indicators

The first indication of a problem is usually an illuminated ALARM LED on the
front panel. In normal operation, only the green (ACTIVE) LED should be lit
(and, in a master station configured for redundant operation, one of the yellow

STBY LEDs).

In a redundant master station, the LEDs show the state of the A and B
transceiver boards. In a non-redundant master station, the LEDs show the state
of the A transceiver board.

Refer to Figure 26 and Table 15 on page 64 for an explanation of the LED
indicators.

Invisible place holder

Figure 26. LED Indicators

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 63

Table 15. Explanation of Front Panel LEDs

LED Name Color Meaning When Lit

ACTIVE
STBY

ALARM

RX ALR

TX ALR
I/O ALR

Green Transceiver board (A or B) is the selected unit.
Yellow Transceive r board (A or B) is currently in stand-by mo de.

(Functional on master station configured for redundant
operation only.)

Red A major or minor alarm event has occurred; use the front

panel’s Active Radio Status screen to list current alarm events
(see page 61).

Red Difficulty receiving—may be due to an antenna problem,

receiver fault, or other condition causing no or a weak received

signal level.
Red Transmit circuitry fault.
Red A data framing or parity error has occurred over the data port.

Problem-Solving Using a Connected PC

Determination of radio status and reprogramming is normally done from a PC
connected to the master station. Useful commands for performing diagnostics
are listed in Table 6 on page 27. For instructions on performing diagnostics
using a connected PC, see “Performing Network-Wide Radio Diagnostics” on
page 65.

Problem-Solving Using the Front Panel Display

The radio includes several useful tools in the Diagnostics and Event Log menus
that can be used to identify system problems. Brief descriptions of Event Log
commands are given below. Other commands useful for performing
diagnostics are listed in Table 13 on page 52. Refer to Section 6.5, Screen
Descriptions, for detailed information about these commands.

Event Log The Event Log is a helpful way to identify system problems. The radio stores

recent events, such as turning the primary power on, in a log that can be
reviewed using the

Event Log screen (for a full description, see “Event Log” on

page 62). In many cases, the events leading up to a failure can be reviewed to
help determine the cause of a problem. Event log messages are also helpful
when calling GE MDS for technical assistance.

• Major alarms generally indicate a hardware failure or other

abnormal condition that will prevent (or hamper) further operation of
the radio link. Generally speaking, major alarms trigger a switch-over
of internal transceiver board assemblies on a master station
configured for redundant operation.

Connections to a relay that is actuated by these alarms are
provided on the rear panel ALARM connector. (See Figure 15 on
page 20.)

• Minor alarms generally will not prevent operation of the radio link,

but may impair performance. This includes out-of-tolerance
conditions, low signal-to-noise ratios, etc. The cause of a minor alarm
should be investigated and corrected to prevent an eventual system
failure.

Connections to a relay that is actuated by these alarms are
provided on the rear panel

ALARM connector. (See Figure 15 on

page 20.)

64 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

System Bench Testing Set-up

Figure 27 shows a sample test setup that can be used to verify the basic
operation of MDS x710 and x790 radios. This test can be performed with any
number of remote radios by using a power divider with the appropriate n umber
of output connections.

The MDS x710 and x790 radios include an internal RTU simulator. Use the
RTU command (see “RTU [ON/OFF/0-80]” on page 39) to poll remote radios.
The command reports the number of polls sent, polls received, and the number
of errors detected.

CAUTION

POSSIBLE

EQUIPMENT

DAMAGE

It is very important to use attenuation between all units in the test setup. The
amount of attenuation required depends on the number of units being tested and
the desired signal strength (RSSI) at each transceiver during th e test. In no case
should a signal greater than –50 dBm be applied to any radio in the test setup.

COMPUTER RUNNING

MDS "POLL.EXE" PROGRAM

REMOTE

REMOTE

REMOTE

REMOTE

MASTER STATION

POWER DIVIDER

POWER ATTENUATORS
 Fixed or adjustable
 5w minimum rating

NON-RADIATING ATTENUATOR
 Install on any unused divider ports
 5w minimum rating

Figure 27. System Bench Test Set-up

7.2 Performing Network-Wide Radio Diagnostics

Radios in a network can be remotely polled by connecting a lapto p or PC running
InSite diagnostics software to any radio in the network. Figure 27 shows an
example of a setup for performing network-wide remote diagnostics.

If a PC is connected to any radio in the network, active messaging (polling
which briefly interrupts payload data transmission) can be performed. To
perform diagnostics without interrupting payload data transmission, connect
the PC to a radio defined as the “root” radio. A radio is defined as a root radio
using the

For more information, see the InSite radio System Management Software
Installation and Operation Guide and online help. A complete explanation of
remote diagnostics can be found in GE MDS’ Network-Wide Diagnostics
System Handbook. See the Handbook for more information about the basic
diagnostic procedures outlined below.

1. Program one radio in the network as the root radio by entering the

2. At the root radio, use the

3. Progra m all other radios in the network as no des by en te ri ng th e

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 65

DTYPE ROOT command (page 34) locally, at the radio.

DTYPE

ROOT command at the radio.

DLINK ON

and

DLINK [baud rate]

commands to

enable network-wide diagnostics and set the baud rate at the diagnostics port.

DTYPE

command at each radio.

NODE

4. Use the

)

DLINK ON

and

DLINK [baud rate]

commands to enable network-wide

diagnostics and set the baud rate at the diagnostics port of each node radio.

5. Connect same-site radios using a null-modem cable at the radios’ diagnostic
ports.

6. Connect a PC on which InSite software is installed to the root radio, or to one
of the nodes, at the radio’s diagnostic port. (This PC may be the PC being
used to collect payload data, as shown in Figure 28.) To connect a PC to the

DIAG.

radio’s

port, an RJ-11 to DB-9 adapter (GE MDS P/N 03-3246A01) is
required. If desired, an adapter cable may be constructed from scratch using
the information shown in Figure 29.

7. Launch the InSite software at the PC. (See the

Software Installation and Operation Guide

InSite Radio System Management

for instructions.)

Invisible place holder

DTYPE

NODE

RTU

DTYPE

ROOT

MASTER STATION

ROOT

DIAGNOSTICS DATA

(TO InSite)

RTU

TO DATA

PORT

DTYPE

NODE

TO

DIAGNOSTICS

PORT

PAYLOAD DATA

(TO SCADA APPLICATION)

RTU

DTYPE

NODE

66 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Figure 28. Network-Wide Remote Diagnostics Setup

1

6

RJ-11 PIN LAYOUT

HOST COMPUTER

Invisible place holder

RJ-11 PLUG

(TO RADIO)

TXD

4

RXD

5

GND

6

Figure 29. RJ-11 to DB-9 Adapter Cable

DB-9 FEMALE

(TO COMPUTER

RXD
TXD

GND

2
3
5

7.3 Replacing Assemblies

Component-level repair of a transceiver board in the field is not recommended
due to the complex nature of the circuitry and the use of surface-mount
technology throughout the radio. Malfunctioning assemblies should be
returned to the factory (or authorised service centre) for repair or replacement.

One approach to field-level servicing is to have spare modules available for the
four easily replaced assemblies—the Main Transceiver Board, Power Supply,
Front Panel, and Internal Duplexer. In this way, a defective assembly can be
quickly removed and replaced with a working unit. The following instructions
describe the removal and installation of these assemblies.

CAUTION

POSSIBLE

EQUIPMENT

DAMAGE

Primary power to the radio must be disconnected before removing or
installing transceiver board or power supply assemblies .

Transceiver Board and Power Supply Assemblies

To remove either of these assemblies, loosen the two captive thumbscrews at
each side of the module, and slide the unit straight out as shown in Figure 30.
(There are no cables to disconnect, as the modules are fitted with in-line
connectors.)

To re-install these modules, make sure that the slides are properly aligned with
the guide slots on the chassis, and push straight in. Tighten the thumbscrews to
secure the assembly.

Invisible place holder

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 67

Figure 30. Main Transceiver and Power Supply Removal

Front Panel

The front panel is secured to the chassis with spring-loaded latches. To remove
the panel, simply pull out at the bottom edge until it is free from the chassis
(Figure 31). You will also need to disconnect the modular cable from the back
of the panel. Reverse these steps to re-install the front panel on the chassis.

Invisible place holder

Figure 31. Front Panel Removal

Internal Duplexer

Troubleshooting the
Internal Duplexer

The internal duplexer allows the radio to transmit and receive at the same time
using one antenna.

NOTE: The radio contains either an internal duplexer for full duplex opera-

tion or an antenna switch for simplex operation. Refer to “Antenna
Switch Module” on page 70 for information on the antenna switch.

If you suspect that the internal duplexer is not functioning properly, perform
the following steps to determine if it needs to be replaced.

1. Measure the RF power out of the antenna jack.
If the power registers approximately +37dBm, the internal duplexer is

functioning correctly.
If the power registers less than +37dBm, proceed with Step 2.

2. Open the radio chassis, locate the TX cable, and disconnect the cable from
vertical interface board (Figure 32).

3. Using an adapter, connect the RF power meter to the SMA connector on the
vertical interface board, key the radio and measure the RF power.

If the power registers +39dBm, the internal duplexer is functioning correctly.
If the power registers less than +39dBm, proceed with Step 4.

4. Use the front panel to switch to the alternate transmitter and again measure
the RF power output.

If the alternate transmitter registers +39dBm, the internal duplexer likely
needs replacing.

5. Before replacing the duplexer, verify that the duplexer frequency and radio
TX frequency match.

68 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Removing the Internal
Duplexer

To remove the internal duplexer, follow these steps:

1. Disconnect the cables from the back of the duplexer as shown in
Figure 32.

Antennna RX Receive

Duplexer

TX Transmit

Vertical Interface
Board

Figure 32. Internal Duplexer Cabling

NOTE: A number of different duplexers can be installed in the radio. While

the physical appearance of the duplexer may vary slightly, its oper­ation and removal remain the same.

CAUTION

POSSIBLE

EQUIPMENT

DAMAGE

2. Remove the four screws that mount the duplexer to the chassis as shown in
Figure 33.

3. Carefully lift the duplexer out of the chassis.

Use care when removing the duplexer. It is fragile and can be easily damaged
which can cause de-tuning.

Duplexer

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 69

Figure 33. Internal Duplexer Removal

Antenna Switch Module

The antenna switch connects the transmitter or receiver circuit to the station
antenna in a simplex radio.

NOTE: The radio contains either an internal duplexer for full duplex opera-

tion or an antenna switch for simplex operation. Refer to “Internal
Duplexer” on page 68 for information on the internal duplexer.

Troubleshooting the
Antenna Switch

Removing the Antenna
Switch

If you suspect that the antenna switch is not functioning properly, perform the
following steps to determine if it needs to be replaced.

1. Measure the RF power out of the antenna jack.
If the power registers approximately +37dBm, the antenna switch is

functioning correctly.
If the power registers less than +37dBm, proceed with Step 2.

2. Open the radio chassis, locate the TX cable, and disconnect the cable from
vertical interface board.

3. Using an adapter, connect the RF power meter to the SMA connector on the
vertical interface board, key the radio and measure the RF power.

If the power registers +39 dBm, the antenna switch is functioning correctly.
If the power registers less than +39dBm, proceed with Step 4.

4. Use the front panel to switch to the alternate transmitter and again measure
the RF power output.

If the alternate transmitter registers +39dBm, the antenna switch likely needs
replacing.

5. Before replacing the antenna switch, make sure that +14vdc is present on pin
2 of J14 and pin 1 is less than 1vdc on the PCB interface.

To remove the antenna switch module:

1. Remove the four screws that mount the antenna switch module to the
chassis as shown in Figure 34.

2. Disconnect the cables from the switch module and lift the module out of the
chassis.

Antenna Switch

Antenna Cable

70 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

TX Transmit Cable

RX Receive Cable

Figure 34. Antenna Switch Module Removal

7.4 Cooling Fan Maintenance

The radio uses cooling fans to cool the main transceiver boards. To ensure that
the fans operate correctly, inspect them on a regular basis and keep them clear
of dust (Figure 3 5).

Figure 35. Location of Cooling Fan

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 71

8.0 TECHNICAL REFERENCE

8.1 Technical Specifications

GENERAL

Size 2RU (88.90 mm/3.5 inch) high

363 mm (14.3 in) deep
437 mm (17.2 in) wide

—includes duplexer and power supply
Weight 9 kg (19.8 lbs.) max
Frequency Range See Section 2.6, Model Number Codes, beginning on

Frequency Step Size 6.25 kHz, 5.0 kHz
System Address 0...65000 (reprogrammable from 10000...65000)

DATA CHARACTERISTICS

Signaling Standard EIA-232
Connector DB-25 Female
Data Rates 110, 300, 1200, 2400, 4800, 9600, 19.2 kbps,

Data Latency 7 ms max at 9.6 kbps
Byte Length 10 or 11 bits

page 6 for the model’s frequency range.

Reprogrammable within two bands; duplexer may

require retuning if moving more than 100 kHz.

38.4 kbps asynchronous

TRANSMITTER SYSTEM

Frequency Stability
Carrier Power Accuracy

Normal
Extreme

Adjacent Channel Power –60 dBc
Spurious Emissions –36 dBm, 9 kHz to 1 GHz

Frequency Range See Section 2.6, Model Number Codes, beginning on

Modulation Type Binary CPFSK
Carrier Power 5 Watts
Duty Cycle Continuous
Output Impedance 50 Ohms
Bandwidth Compatibility 12.5 kHz
Harmonics

2nd harmonic
3rd harmonic and higher

Transmitter Keying Data activated or R TS

±1.5 ppm

±1.5 dB

+2 dB to –3 dB

–30 dBm, 1 GHz to 12 GHz

page 6 for model details.

–73 dBc

–67 dBc

72 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

RECEIVER SYSTEM

Maximum Usable
Sensitivity

Co-Channel Rejection –12 dB
Adjacent Channel

Selectivity

Normal Test
Extreme Test

Spurious Response
Rejection

Frequency Range See Section 2.6, Model Number Codes, beginning on

Type Double conversion superheterodyne
Frequency Stability

Errors at High Input Levels
Bandwidth 12.5 kHz

–110 dBm at 10

60 dB

50 dB

70 dB

page 6 for model details.

±1.5 ppm

+1 dBm at BER 10

–6

BER

-4

PRIMARY POWER

Supply Voltage 1 00–240 Vac @ 1.4–0.7 A nominal

ENVIRONMENTAL

Temperature Range
Humidity
Shock and Vibration Per MIL-810E (shipping)

24 Vdc nominal

48 Vdc nominal

125 Vac to 12 Vdc with external converter

Full performance: –30 to 60 °C

95% at 40

°C, non-condensing

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 73

8.2 RF Propagation Planning

B

Establishing a reliable point-to-point radio link requires system planning and
design. It is helpful to have an understanding of the physical parameters
affecting propagation. The following material discusses these factors and will
assist you in designing a dependable transmission path for your radio link.

NOTE: This section is intended for use as a guideline when planning trans-

mission paths. It does not consider all of the local conditions that
may be present, nor does it guarantee that adequate signal strength
will be obtained in a given system. There is no substitute for an
on-the-air test to verify the predicted path results, and to check the
overall operation of the radio system.

To ensure a highly reliable path, a line of sight between both ends of the link
is desirable. For short paths (up to 5 kilometers/3.1 miles), some obstructions
may be acceptable, but the performance of a blocked path is always less
predictable than a clear path.

Fresnel Zone Clearance

As the distance spanned by a link gets longer, it is necessary to have more than
just a grazing path between the two ends; the path must clear the ground or
other obstacles by some percentage of a Fresnel zone.

The Fresnel zone corresponds to the width or girth of the radio signal. There
are first, second, and third Fresnel zones, but the first zone is the only one that
has substantial effects on signal strength.

The first Fresnel zone can be visualized as an oval-shaped volume between two
station antennas (Figure 36). As the width of the radio wave front gets blocked
by obstructions, less of the signal can get to the receiver antenna.

In addition to blocking the signal, obstructions in the first Fresnel zone may
also cause multipath interference due to reflective and refractive signal paths.
The reflected or refracted signal may arrive at the receiver out of phase with
the desired signal and cause a cancelling effect.

Invisible place holder

LINE-OF-SIGHT (LOS)

STATION A

Distance D

1

Figure 36. Fresnel Zone Obstructions

As a matter of practice, 60 percent of the first Fresnel zone must be clear of
obstructions (0.6 x F) to allow a clear, unobstructed RF path.

Remember, the first Fresnel zone calculation is only one parameter
determining path quality.

74 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

FRESNEL ZONE

F

OBSTRUCTION

Distance D

2

NOT

OBSTRUCTING

STATION

Earth Curvature

)

As the distance of a communication link increases, the clearance problem is
compounded by the earth’s curvature. Radio waves traveling through typical
atmospheric conditions bend slightly, which is represented by treating the earth
as though it were slightly flatter than it actually is. Experience has shown that
if we consider the earth’s radius to be 4/3rds of its actual size, we get good
agreement between theory and measured propagation results.

Figure 37 shows a representation of the 4/3 earth “radio horizon.” This figure
shows that under normal radio propagation conditions, a station with its
antenna 15 meters above flat terrain will have a radio horizon approximately
15 kilometers away, well beyond the visual horizon.

Invisible place holder

76

(250)

61

(200)

Antenna

Height in

Meters

(Feet)

46

(150)

30

(100)

15

(50)

0

(0)

(0)0(2) (4) (6) (8) (10) (12) (14) (16) (18) (20) (22) (24) (26) (28) (30) (32) (34)

Radio Horizon Over Level Terrain in Kilometers (Miles)

Normal Conditions

(36

585552484542393532 292623191610 1363

Figure 37. Antenna Height vs. Theoretical Radio Horizon

Fade Margins

Variations in the temperature and humidity of the atmosphere with elevation
cause the signals to bend more or less, resulting in fading at the receiver. The
longer the path is, the more likely that deep fades will occur, hence the greater
the fade margin required.

Different parts of the world have differing propagation conditions, which can
be categorised as favorable, average, or adverse. In general, mountainous areas
have favorable propagation conditions, while tropical areas and those near
large bodies of water have adverse conditions.

Calculating Path Loss

Assuming that we have satisfied the line-of-sight and first Fresnel zone
clearance requirements, we can calculate the path loss. At 450 MHz, the loss
between two isotropic radiators (0 dBi antennas) that are 1 km apart is 86 dB.
For every doubling of distance, the loss increases by an additional 6 dB.
Knowing this, the output power (+37 dBm), and the receiver sensitivity (–115
dBm), we can calculate antenna size and tower height requirements to cover
any desired distance.

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 75

8.3 Formulas for System Planning

The following standard formulas are provided for assistance in determining
system installation parameters.

Free Space Path Loss

α

fs

α

= free space loss in dB

fs

d = path distance in kilometers
ƒ = frequency in GHz

92.4 20

flog 20

10

Fresnel Zone Boundary

nd1d

⋅

fD

2

where:

1+d2

F

17.3

=

n

--------------------

Fn = Fresnel zone boundary in meters

= distance from one end of the path to the Fresnel zone boundary (in

d

1

kilometers)

= distance from the other end of the path to the Fresnel zone

d

2

boundary (in kilometers)

D = total path distance (d

ƒ = frequency in GHz
n = Fresnel zone, 1 (for 1st) is used here

Theoretical Signal Strength

RSSI EIRP α–

RSSI = signal strength at the receiver in dBm

EIRP = RF power outp ut in dBm + Gta –L

= free-space path loss in dB

α

fs

= receive antenna gain in dBi

G

ra

= receive feedline loss in dB

L

rfl

= transmit feedline loss in dB

L

tfl

= transmit antenna gain in dBi

G

ta

fs

G

ra

–+=

dlog++=

10

) in kilometers

where:

L

rfl

tfl

where:

Probability of System Fading

FProb a b 6.0 10

76 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

7–

fd310

FProb = probability of fading more than F

a =terrain factor

• 4 is used for very smooth terrain, such as over water

• 1 is used for average terrain, with moderate roughness

• 0.25 is used for mountainous or very rough terrain

b = climate factor

• 0.5 is used for a hot, humid climate

• 0.25 is used for temperate or northern areas

• 0.125 is used for a very dry climate

ƒ = frequency in GHz
d = path length in km

F = fade margin in dB

××××××=

where:

F–()10⁄

8.4 Frequency Reference Chart

Table 16 lists the transmit frequencies assigned to UK private fixed telemetry
and telecontrol radio services (as of the manual publication date). Group A fre­quencies are those normally assigned to stations operating in this service.
Group B frequencies are “interleave” channels that are offset from the Group
A frequencies by 6.25 kHz. The assignment of interleave channels is consid­ered on a case-by-case basis.

Users are responsible to ensure that their operation is on authorised frequencies
as stated by the station licence. Inquiries on UK regulatory compliance should
be directed to:

Radiocommunications Agency
Fixed Services Section
Room 309
Waterloo Bridge House
Waterloo Road
London SE1 8UA

Table 16. MPT 1411 Transmit Frequencies

Channel Nominally

Interference

Free

Group A Group B Group A Group B Group A Group B

1 457.50625 457.51250 463.00625 463.01250
2 Y 457.51875 457.52500 463.01875 463.02500
3 Y 457.53125 457.53750 463.03125 463.03750
4 457.54375 457.55000 463.04375 463.05000
5 Y 457.55625 457.56250 463.05625 463.06250
6 457.56875 457.57500 463.06875 463.07500
7 Y 457.58125 457.58750 463.08125 463.08750
8 457.59375 457.60000 463.09375 463.10000

9 457.60625 457.61250 463.10625 463.11250
10 Y 457.61875 457.62500 463.11875 463.12500
11 Y 457.63125 457.63750 463.13125 463.13750
12 457.64375 457.65000 463.14375 463.15000
13 Y 457.65625 457.66250 463.15625 463.16250
14 457.66875 457.67500 463.16875 463.17500
15 Y 457.68125 457.68750 463.18125 463.18750
16 457.69375 457.70000 463.19375 463.20000
17 457.70625 457.71250 463.20625 463.21250
18 Y 457.71875 457.72500 463.21875 463.22500
19 Y 457.73125 457.73750 463.23125 463.23750
20 457.74375 457.75000 463.24375 463.25000
21 Y 457.75625 457.76250 463.25625 463.26250
22 457.76875 457.77500 463.26875 463.27500
23 Y 457.78125 457.78750 463.28125 463.28750

Master Stations

(Scanner)

Remote Station

(Outstations)

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 77

Table 16. MPT 1411 Transmit Frequencies (Continued)

Channel Nominally

Interference

Master Stations

(Scanner)

Remote Station

(Outstations)

Free

Group A Group B Group A Group B Group A Group B

24 457.79375 457.80000 463.29375 463.30000
25 457.80625 457.81250 463.30625 463.31250
26 Y 457.81875 457.82500 463.31875 463.32500
27 Y 457.83125 457.83750 463.33125 463.33750
28 457.84375 457.85000 463.34375 463.35000
29 Y 457.85625 457.86250 463.35625 463.36250
30 457.86875 457.87500 463.36875 463.37500
31 Y 457.88125 457.88750 463.38125 463.38750
32 457.89375 457.90000 463.39375 463.40000
33 457.90625 457.91250 463.40625 463.41250
34 Y 457.91875 457.92500 463.41875 463.42500
35 Y 457.93125 457.93750 463.43125 463.43750
36 457.94375 457.95000 463.44375 463,45000
37 Y 457.95625 457.96250 463.45625 463.46250
38 457.96875 457.97500 463.46875 463.47500
39 Y 457.98125 457.98750 463.48125 463.48750
40 457.99375 458.00000 463.49375 463.50000
41 458.00625 458.01250 463.50625 463.51250
42 y 458.01875 458.02500 463.51875 463.52500
43 y 458.03125 458.03750 463.53125 463.53750
44 458.04375 458.05000 463.54375 463.55000
45 y 458.05625 458.06250 463.55625 463.56250
46 458.06875 458.07500 463.56875 463.57500
47 y 458.08125 458.08750 463.58125 463.58750
48 458.09375 458.10000 463.59375 463.60000
49 458.10625 458.11250 463.60625 463.61250
50 458.11875 458.12500 463.61875 463.62500
51 Y 458.13125 458.13750 463.63125 463.63750
52 458.14375 458.15000 463.64375 463.65000
53 Y 458.15625 458.16250 463.65625 463.66250
54 458.16875 458.17500 463.66875 463.67500
55 458.18125 458.18750 463.68125 463.68750
56 458.19375 458.20000 463.69375 463.70000
57 458.20625 458.21250 463.70625 463.71250
58 Y 458.21875 458.22500 463.71875 463.72500
59 Y 458.23125 458.23750 463.73125 463.73750
60 458.24375 458.25000 463.74375 463.75000

78 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Table 16. MPT 1411 Transmit Frequencies (Continued)

Channel Nominally

Interference

Master Stations

(Scanner)

Remote Station

(Outstations)

Free

Group A Group B Group A Group B Group A Group B

61 Y 458.25625 458.26250 463.75625 463.76250
62 458.26875 458.27500 463.76875 463.77500
63 Y 458.28125 458.28750 463.78125 463.78750
64 458.29375 458.30000 463.79375 463.80000
65 458.30625 458.31250 463.80625 463.81250
66 458.31875 458.32500 463.81875 463.82500
67 Y 458.33125 458.33750 463.83125 463.83750
68 458.34375 458.35000 463.84375 463.85000
69 Y 458.35625 458.36250 463.85625 463.86250
70 458.36875 458.37500 463.86875 463.87500
71 458.38125 458.38750 463.88125 463.88750
72 458.39375 458.40000 463.89375 463.90000
73 458.40625 458.41250 463.90625 463.91250
74 Y 458.41875 458.42500 463.91875 463.92500
75 Y 458.43125 458.43750 463.93125 463.93750
76 458.44375 458.45000 463.94375 463.95000
77 Y 458.45625 458.46250 463.95625 463.96250
78 458.46875 458.47500 463.96875 463.97500
79 458.48125 458.48750 463.98125 463.98750
80 458.49375 463.99375

MDS 05-3628A01, Rev . B MDS 4790M (MPT 1411) I/O Guide 79

8.5 dBm-Volts-watts Conversion Chart

Table 17 is provided as a convenience for determining the equivalent voltage
or wattage of an RF power expressed in dBm.

Table 17. dBm-Volts-Watts Conversion Chart

dBm V Po

+53 100.0 200W
+50 70.7 100W
+49 64.0 80W
+48 58.0 64W
+47 50.0 50W
+46 44.5 40W
+45 40.0 32W
+44 32.5 25W
+43 32.0 20W
+42 28.0 16W
+41 26.2 12.5W
+40 22.5 10W
+39 20.0 8W
+38 18.0 6.4W
+37 16.0 5W
+36 14.1 4W
+35 12.5 3.2W
+34 11.5 2.5W
+33 10.0 2W
+32 9.0 1.6W
+31 8.0 1.25W
+30 7.10 1.0W
+29 6.40 800mW
+28 5.80 640mW
+27 5.00 500mW
+26 4.45 400mW
+25 4.00 320mW
+24 3.55 250mW
+23 3.20 200mW
+22 2.80 160mW
+21 2.52 125mW
+20 2.25 100mW
+19 2.00 80mW
+18 1.80 64mW
+17 1.60 50mW
+16 1.41 40mW
+15 1.25 32mW
+14 1.15 25mW
+13 1.00 20mW
+12 .90 16mW
+11 .80 12.5mW
+10 .71 10mW
+9 .64 8mW
+8 .58 6.4mW
+7 .500 5mW
+6 .445 4mW
+5 .400 3.2mW
+4 .355 2.5mW
+3 .320 2.0mW
+2 .280 1.6mW
+1 .252 1.25mW

dBm V Po

0 .225 1.0mW

-1 .200 .80mW

-2 .180 .64mW

-3 .160 .50mW

-4 .141 .40mW

-5 .125 .32mW

-6 .115 .25mW

-7 .100 .20mW

-8 .090 .16mW

-9 .080 .125mW

-10 .071 .10mW

-11 .064

-12 .058

-13 .050

-14 .045

-15 .040

-16 .0355

dBm mV Po

-17 31.5

-18 28.5

-19 25.1

-20 22.5 .01mW

-21 20.0

-22 17.9

-23 15.9

-24 14.1

-25 12.8

-26 11.5

-27 10.0

-28 8.9

-29 8.0

-30 7.1 .001mW

-31 6.25

-32 5.8

-33 5.0

-34 4.5

-35 4.0

-36 3.5

-37 3.2

-38 2.85

-39 2.5

-40 2.25 .1µW

-41 2.0

-42 1.8

-43 1.6

-44 1.4

-45 1.25

-46 1.18

-47 1.00

-48 0.90

dBm mV Po

-49 0.80

-50 0.71 .01µW

-51 0.64

-52 0.57

-53 0.50

-54 0.45

-55 0.40

-56 0.351

-57 0.32

-58 0.286

-59 0.251

-60 0.225 .001µW

-61 0.200

-62 0.180

-63 0.160

-64 0.141

dBm µV Po

-65 128

-66 115

-67 100

-68 90

-69 80

-70 71 .1nW

-71 65

-72 58

-73 50

-74 45

-75 40

-76 35

-77 32

-78 29

-79 25

-80 22.5 .01nW

-81 20.0

-82 18.0

-83 16.0

-84 11.1

-85 12.9

-86 11.5

-87 10.0

-88 9.0

-89 8.0

-90 7.1 .001nW

-91 6.1

-92 5.75

-93 5.0

-94 4.5

-95 4.0

-96 3.51

-97 3.2

dBm µV Po

-98 2.9

-99 2.51

-100 2.25 .1pW

-101 2.0

-102 1.8

-103 1.6

-104 1.41

-105 1.27

-106 1.18

dBm nV Po

-107 1000

-108 900

-109 800

-110 710 .01pW

-111 640

-112 580

-113 500

-114 450

-115 400

-116 355

-117 325

-118 285

-119 251

-120 225 .001pW

-121 200

-122 180

-123 160

-124 141

-125 128

-126 117

-127 100

-128 90

-129 80 .1ƒW

-130 71

-131 61

-132 58

-133 50

-134 45

-135 40

-136 35

-137 33

-138 29

-139 25

-140 23 .01ƒW

80 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

INDEX

A

Access Level screen 53
Accessories 5
ACTIVE LED 22
Active messaging (defined) 6
Active Radio Status screen 61
ALARM command (display current alarm status in

hexadecimal format). See also STAT com ma n d 28
ALARM LED 22
Alarm Masks screen 59
Alarms

classify events as major (AMASK command) 30
classify events as minor (NMASK command) 36
connecting optional circuits 19
display hexadecimal codes (LCD screen) 59
display status (ST AT command). See also ALARM

command 41
event codes 42
hexadecimal values for major alarm conditions, table 29
hexadecimal values for minor alarm conditions, table 29
major, defined 64
minor, defined 64
relay connections, illustrated 20
set/display Pin 25 alarm output (ASENSE command) 31
summarize in hexadecimal format (ALARM command) 28

AMASK command (classify alarm events as major). See also

NMASK command 30

Antenna switch module

removing or re-installing 70
removing, illustrated 70

Antennas

height vs. theoretical radio horizon, illustrated 75
selection 10

ASENSE command (set/display Pin 25 alarm output) 31
Assemblies, replacing 67
Audio

connector, illustrated 20
connector, installation 20
enable/disable receive attenuator (LCD screen) 58
enable/disable transmit boost (LCD screen) 58
enable/disable transmit boost (TXGAIN command) 44
set/display receive level (LCD screen) 58
set/display receive level (RXLEVEL command) 39
set/display transmit level (LCD screen) 58
set/display transmit level (TXLEVEL command) 44

B

Backlight Intensity screen 59
Backup Battery Cable

location 15

Battery, connecting back-up 19
BAUD command (set/display communication attributes for

DATA INTERFACE port) 31

Baud rate

set/display baud rate/format (Baud Rate/Format screen) 54

setting for RJ-11 DIAG port (DLINK command) 33, 65
Baud Rate/Format screen 54
Bench test setup 65

illustrated 65
BER (bit-error rate), defined 6
BERT (bit-error rate test), defined 6
Bit, defined 6
bps (bits-per-second), defined 6
BUFF command (set/display received data handling mode) 31
Byte, defined 6

C

Cables

coax 10, 17

DB-9 to DB-9 for PC connection 24

DB-9 to DB-9, illustrated 24

diagnostic and control interface, accessory 5

extension 13

feedline installation 16

feedline loss chart, table 11

feedline selection 10

front panel, disconnecting 13, 68

null-modem, connecting same-site radios for

diagnostics 66
RJ-11 to DB-9 adapter 66
RJ-11 to DB-9 adapter, illustrated 66

Cautions

disconnect primary power before removing transceiver

board or power supply 67, 69
verify power source matches power supply 15

CKEY command (enable/disable continuous keying) 32
Clear Logs screen 62
Clear-to-Send Delay screen 55
Clear-to-send timer

set/display value (CTS command) 32
set/display value (LCD screen) 55

Commands

ALARM (display current alarm status in hexadecimal

format). See also STAT command 28
AMASK (classify alarm events as major). See also

NMASK command 30
ASENSE (set/display Pin 25 alarm output) 31
BAUD (set/display communication attributes for DATA

INTERF ACE port) 31
BUFF (set/display received data handling mode) 31
CKEY (enable/disable continuous keying) 32
CTS (set/display clear-to-send timer) 32
DATAKEY (set/display key-on-data mode) 33
DATE (set/display date) 33
diagnostics, PC 27
DKEY (deactivate transmitter). See also KEY command 33
DLINK (enable/disable network-wide diagnostics) 33
DMGAP (set time to wait between characters) 34
DTYPE (set radio to root or node for diagnostics) 34
DUMP (display radio status) 34
HREV (display hardware revision level) 35

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide I-1

INIT (reset customer-programmable settings) 35
KEY (activate transmitter). See also DKEY command 35
LOG (display/clear history of system events) 36
MODE (display whether master or remote) 36
MODEL (display radio model number) 36
MODEM (set modem speed) 36
NMASK (classify minor alarm events). See also AMASK

command 36
OPT! (list installed radio options) 37
OWM command (set/display text message) 37
OWN command (set/display text message) 37
owner and radio information, PC 28
PC, summarized 24–28
PROG (upgrade internal software) 37
PTT (set/display push-to-talk delay) 38
RADIO (set/display active transceiver board) 38
radio operation, PC 25
REPEATER (enable/disable repeater configuration) 38
RSSI, RSSI! (display received signal strength

indication) 38
RTU (enable/disable internal RTU) 39
RX (set/display receive frequency) 39
RXLEVEL (set/display audio receive level) 39
RXPAD (enable/disable receive attenuator) 40
RXTOT (set/display receive time-out timer value) 40
SCD (set/display soft carrier de-key delay) 40
SER (display radio serial number) 40
SHOW (display various settings) 40
SNR, SNR! (display signal-to-noise ratio) 41
SREV (display software release information) 41
STAT (display alarm status). See also ALARM

command 41
TEMP (display internal temperature) 42
TIME (set/display time) 43
TOT (set/display time-out timer) 43
TX (set/display transmit frequency) 43
TXGAIN (enable/disable transmit audio boost) 44
TXLEVEL (set/display transmit audio level) 44
UNIT (set/display radio’s address) 44

Connector

analog orderwire (voice communications) 19
analog orderwire, illustrated 17

Continuous Keying screen 56
Controls

front panel 47
front panel, illustrated 21, 47
using to configure radio 48

Cooling fan

location, illustrated 71

cooling fan maintenance 71
CTS command (set/display clear-to-send timer) 32

D

Data

characteristics 72
connector pinouts, table 18
connector, illustrated 17
connector, installing 17
enable/disable buffering (LCD screen) 57, 58

Data Buffering screen 57, 58
Data interface port

set display communication attributes for (BAUD

command) 31
set/display received data handling mode (BUFF

command) 31

DATAKEY command (set/display key-on-data mode) 33
DATE command (set/display date) 33
dBi, defined 6
dBm

conversion to watts or volts, table 80
defined 6

DCE (Data Circuit T e rminating Communicatio ns Equipment),

defined 7
Decibel (dB), defined 7
Diagnostic port

cable connecting PC to radio 24
connecting 19
J1 pin connections, illustrated 19

Diagnostics 23–62

connecting a PC to the radio for 24
network-wide setup, illustrated 66
using LCD screens 64

Display

active connector port (SHOW command) 40
active transceiver board (RADIO command) 38
active transceiver board (Radio Selection screen) 61
active transceiver board’s serial number (Serial Number

screen) 62
actual RF power output (SHOW command) 40
alarm conditions (Active Radio Status screen) 61
alarm status in hexadecimal format (ALARM

command) 28
audio receive level (Receive Level screen) 58
audio receive level (RXLEVEL command) 39
baud rate/format (Baud Rate/Format screen) 54
clear-to-send delay (Clear-to-Send Delay screen) 55
clear-to-send delay (CTS command) 32
communications attributes for data interface port (BAUD

command) 31
continuous key time-out (TOT command) 43
data handling mode (BUFF command) 31
date (DATE command) 33
date (Set Date screen) 60
DC input/output voltages (SHOW command) 40
event history (Event Log screen) 62
hardware revision level (HREV command) 35
hexadecimal alarm codes (Alarm Masks screen) 59
hexadecimal major alarm codes (AMASK command) 30
hexadecimal minor alarm codes (NMASK command) 36
history of system events (LOG command) 36
intensity of LCD characters (Display Contrast screen) 59
internal modem speed (Modem screen) 54
internal temperature (TEMP command) 42
internal temperature and voltages (LCD screen) 62
keying mode (continuous, DCE) (Continuous Keying

screen) 56
keying mode (key-on-data, key-on-RTS) (Key On Data

screen) 57
key-on-data mode (DATAKEY command) 3 3
LCD background brightness (Backlight Intensity

screen) 59
list of installed radio options (OPT! command) 37
output power (Output Power screen) 54
owner message (OWM command) 37
owner message (Set Owner Message screen) 60
owner name (OWN command) 37
owner name (Set Owner Name screen) 59
Pin 25 alarm output (ASENSE command) 31
push-to-talk delay (PTT command) 38
push-to-talk delay (Push-to-Talk Delay screen) 55
radio address (Unit Address screen) 57

I-2 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

radio address (UNIT command) 44
radio configuration (master/remote) (MODE command) 36
radio configuration (root/node) (DTYPE command) 34
radio model number (MODEL command) 36
radio serial number (SER command) 40
radio status (DUMP command) 34
receive frequency (Receive Frequency screen) 54
receive frequency (RX command) 39
receive time-out timer value (RXTOT command) 40
received signal strength (Receive Signal Strength

screen) 61
received signal strength (RSSI, RSSI! commands) 38
repeater mode (Repeater Mode screen) 56
RX timeout (RX Timeout screen) 56
signal-to-noise ratio (S/N Ratio screen) 61
signal-to-noise ratio (SNR, SNR! commands) 41
soft carrier de-key delay (SCD command) 40
soft carrier de-key delay (Soft Carrier De-Key Delay

screen) 55
software release information (Software Revision screen) 62
software release information (SREV command) 41
start of new message timer (DMGAP command) 34
time (Set Time screen) 60
time (TIME command) 43
transmit audio level (TXLEVEL command) 44
transmit frequency (Transmit Frequency screen) 53
transmit frequency (TX command) 43
transmit level (Transmit Level screen) 58
transmit timeout (Transmit Timeout screen) 55
transmit timeout duration (Transmit Timeout Duration

screen) 55
transmitter state (Manual Key screen) 56
transmitter state (Transmitter Status screen) 62

Display Contrast screen 59
DKEY command (deactivate transmitter). See also KEY

command 33

DLINK command

enable/disable network-wide diagnostics, description 33
use of 65

DMGAP command (set time to wait between characters) 34
DSP (Digital Signal Processing), defined 7
DTE (Data Terminal Equipment), defined 7
DTYPE command

set radio to root or node for diagnostics, description 34
use of 65

DUMP command

display radio status 34

E

Emphasis

enable/disable (Emphasis screen) 54

Emphasis screen 54
Enable/disable

audio transmit boost (Transmit Gain screen) 58
continuous keying (CKEY command) 32
data buffering (Data Buffering screen) 57, 58
emphasis and de-emphasis (Emphasis screen) 54
internal RTU (RTU command) 39
network-wide diagnostics (DLINK command) 33
network-wide diagnostics, procedures 65
receive attenuator (Receive Pad screen) 58
receive attenuator (RXPAD command) 40
repeater operation (REPEATER command) 38
transmit audio boost (TXGAIN command) 44
transmit timeout timer (Transmit Timeout screen) 55

ENTER button

use in display-only mode 47
use in radio configuration 48

ESCAPE button

use in display-only mode 47
use in radio configuration 48

Event codes 42

major alarms, defined 64
minor alarms, defined 64

Event log

use in problem solving 64

Event Log screen 62

F

Fade margin

defined 7

discussion 75
Fading, calculating probability of system 76
Feedline

installing 16

loss chart 11

selection 10
Formulas 76

free space path loss 76

Fresnel zone boundary 76

probability of system fading 76

theoretical signal strength 76
Frame, defined 7
Frequency

in simplex or switched carrier operation 5

preventing unnecessary use of (Transmit Timeout

screen) 55
range 72
receiver range 73
receiver stability 73
set/display receive (Receive Frequency screen) 54
set/display receive (RX command) 39
set/display transmit (Transmit Frequency screen) 53
set/display transmit (TX command) 43
stability 72
step size 72
transmitter range 72

Fresnel zone

boundary, formula 76
clearance 74
defined 7
obstructions, illustrated 74

Front panel

controls, illustrated 47
ENTER button 47
ESCAPE button 47
illustrated 21
indicators 21
LCD display 23
left/right arrow buttons 47
removing 13
removing or re-installing 68
removing, illustrated 68
up/down arrow buttons 47

G

Glossary 6

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide I-3

H

Half-power beamwidth, defined 7
Hardware, display revision level (HREV command) 35
Hexadecimal

alarm code display (Alarm Masks screen) 59
summarize alarms in (ALARM command) 28
use to classify events as major alarms (AMASK

command) 30

use to classify events as major alarms (NMASK

command) 36
values for major alarm conditions 29
values for minor alarm conditions 29

HREV command (display hardware revision level) 35

I

I/O ALR LED 22
Illustrations

antenna height vs. theoretical radio horizon 75
Antenna switch module removal 70
audio connections 20
bench test setup 65
data connector 17
DC power supply 14
diagnostics port J1 pin connections 19
Fresnel zone 74
front panel controls and indicators 21
front panel removal 13, 68
internal duplexer removal 69
LCD menu flowchart 46
LCD start-up screen 23
LED indicators 22, 63
main transceiver and power supply removal 67
MAS network 4
MDS 4790A master station 2
model number codes 6
mounting dimensions and bracket details 12
network-wide diagnostics 66
network-wide remote diagnostics setup 66
PC connected to the master station 23
PC diagnostic port cable 24
programming and control buttons 47
rear panel 17
repeater and polling-remote network 4
RJ-11 to DB-9 adapter cable 66
shipment contents 11
station arrangement 8

INIT command (reset customer-programmable settings) 35
Installation

alarm contacts and battery back-up connections 19
antenna and feedline selection 10
audio connector 20
battery power, connecting 14
data connector 17
diagnostics port connection 19
feedline 16
interface wiring connections 17
interference 9
mounting 12
on-the-air test 9
planning 8–??
primary power, connecting 13
procedures 11–21
quick start instructions. See inside front cover
rack mounting 12

remote front panel mounting 12
requirements 8
site selection 8
tabletop mounting 12
terrain and signal strength 9

Installation planning

antenna height vs. theoretical radio horizon, illustrated 75
calculating path loss 75
earth curvature 75
fade margins 75
formulas for system planning 76
Fresnel zone clearance 74
Fresnel zone, illustrated 74
RF propagation 74

Internal duplexer

removing or re-installing 68
removing, illustrated 69

K

kbps (kilobits-per-second), defined 7
KEY command (activate transmitter). See also DKEY

command 35
Key On Data screen 57
Keying

activate transmitter (KEY command). See also DKEY

command 35
activate transmitter (Manual Key screen) 56
de-key transmitter (DKEY command). See also KEY

command 33
de-key transmitter (Manual Key screen) 56
enable/disable continuous (CKEY command) 32
set/display mode (continuous, DCE) (Continuous Keying

screen) 56
set/display mode (key-on-data, key-on-RTS) (Key On Data

screen) 57

L

LCD 23

Backlight Intensity screen 59
diagnostics commands, table 52
Display Contrast screen 59
main screens 53
Menu Directory screen 53
menu flowchart 46
operating parameters commands, table 50
owner and radio information commands, table 52
screen descriptions 49–62
screens, navigation 47
set background brightness (Background Intensity

screen) 59
set character intensity (Display Contrast screen) 59
start-up screen 53
start-up screen, illustrated 23
toggle between display-only and configuration modes 48
toggle between display-only and radio configuration modes

(Access Level screen) 53
use in problem solving 64
using to set radio functions 48

LEDs 22

description, table 64
explanation of front panel 22
illustrated 22, 63
normal indications 21
use in problem solving 63

I-4 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

left/right arrow buttons 47
LOG command (display/clear history of system events) 36

M

Maintenance

cooling fan 71
Manual Key screen 56
MAS operation 4

illustrated 4
Menu directory

displaying 47

displaying individual menu screens 48

illustrated 47

selecting a main menu item 47

selection arrow 47
Menu Directory screen 53
MODE command (display whether master or remote) 36
MODEL command (display radio model number) 36
Model number

codes, illustrated 6

display radio (PC command) 36
MODEM command 36
Modem screen 54
Modem, set speed. See MODEM command
Modem, set/display internal speed (Modem screen) 54
Mounting the radio 12

dimensions and bracket details, illustrated 12

rack mount 12

remote front panel mount 12

tabletop mount 12
Multipath fading, defined 7

N

Network-wide diagnostics

active messaging, defined 6

defined 7

enable/disable (DLINK command) 33

enable/disable internal RTU (RTU command) 39

illustrated 66

passive messaging, defined 7

set radio to root or node (DTYPE command) 34

set time to wait between characters (DMGAP

command) 34

NMASK command (classify minor alarm events). See also

AMASK command 36

Non-intrusive diagnostics. See Passive messaging

O

Operation 21–48

normal indications 21

start-up 21
OPT! command (list installed radio options 37
Options

list installed (OPT! command) 37

radio accessories 5
Orderwire 19
Output Power screen 54
OWM command (set/display text message) 37
OWN command (set/display text message) 37

P

Packaging for shipment. See inside rear cover
Passive messaging, defined 7
Path loss

calculating 75

free space, formula 76
Payload data, defined 7
PC

command summaries 24–28

commands, detailed descriptions 28–??

connected to the master station, illustrated 23

connecting to the radio for diagnostics and control 24

diagnostic port cable, illustrated 24

use in problem solving 64
Performance testing 65
Pinouts

set/display Pin 25 alarm output (ASENSE command) 31
Polling-remote operation 4

illustrated 4
Power

AC-powered units 13

back-up battery, connecting 19

connecting battery 14

connecting primary 13

DC power supply, illustrated 14

DC-powered units 13

display actual RF output (SHOW command) 40

primary, specifications 73

set/display output (Output Power screen) 54

supply assembly 67

supply removal, illustrated 67
Problem solving 63–71

at the local level 63

bench test setup 65

use of event log in 64

using a connected PC 64

using LCD display 64

using LED indicators 63
Procedures

assembly replacement 67

bench test 65

changing radio functions 48

connecting battery power 14

connecting interface wiring 17

connecting PC for diagnostics 24

connecting primary power 13

diagnostics 63–71

diagnostics using connected PC 64

diagnostics using event log 64

diagnostics using LED indicators 63

diagnostics, local 63–65

feedline installation 16

installation 11–21

installation planning 8–??

mounting the radio 12

navigating LCD screens 47

post-installation checks 20

start-up and operation 21–48

toggle between display-only and configuration modes 48
Product

returning for service. See inside rear cover
PROG command (upgrade internal software) 37
Programming radio as root or node 65
PTT command (set/display push-to-talk delay) 38
Push-to-Talk Delay screen 55

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide I-5

Q

Quick start instructions. See inside front cover

R

Radio

accessories 5
description 1
display model number (PC command) 36
display serial number (SER command) 40
display software revision number (Software Revision

screen) 62
display transmitter state (LCD screen) 62
illustrated 2
key features 5
model number codes 6
model number codes, illustrated 6
removing antenna switch module 70
removing internal duplexer 68
removing or re-installing front panel 68
set date (LCD screen) 60
set time (LCD screen) 60
set/display active transceiver board (LCD screen) 61
set/display address (Unit Address screen) 57
set/display address (UNIT command) 44
using LCD to set functions 48

RADIO command (set/display active transceiver board) 38
Radio Selection screen 61
Receive attenuator, enable/disable (Receive Pad screen) 58
Receive Frequency screen 54
Receive Level screen 58
Receive Pad screen 58
Receive Signal Strength screen 61
Receiver specifications 73
Redundancy 3
Remote

Station, defined 7

Removing

antenna switch module 70
Antenna switch module, illustrated 70
assemblies 67
front panel 68
front panel, illustrated 68
internal duplexer 68
internal duplexer, illustrated 69
transceiver boards, about 67

REPEATER command (enable/disable repeater

configuration) 38
Repeater Mode screen 56
Repeater operation 4

illustrated 4
set/display (Repeater Mode screen) 56

Replacing

assemblies 67

transceiver board 67
Requirements for installation 8
RF propagation planning 74
RMA number (returning product for service). See inside rear

cover

RSSI

defined 8

display (LCD screen) 61

maximizing 21

theoretical signal strength, formula 76
RSSI, RSSI! commands (display received signal strength

indication) 38

RTU (Remote Terminal Unit)

command (enable/disable internal RTU) 39
defined 8

internal simulator 65
RX ALR LED 22
RX command (set/display receive frequency) 39
RX Timeout screen 56
RX timeout, set/display (RX Timeout screen) 56
RXLEVEL command (set/display audio receive level) 39
RXPAD command (enable/disable receive attenuator) 40
RXTOT command 40

S

S/N Ratio screen 61
SCD command (set/display soft carrier de-key delay) 40
Screens

Access Level screen 53

Active Radio Status 61

Alarm Masks 59

Backlight Intensity 59

Baud Rate/Format 54

Clear Logs 62

Clear-to-Send Delay 55

configuration 53–60

configuration, listed 49

Continuous Keying 56

Data Buffering 57, 58

diagnostic, listed 49

Display Contrast 59

displaying individual 48

Emphasis 54

Event Log 62

Key On Data 57

main 53

Manual Key 56

Menu Directory screen 53

menu directory, illustrated 47

menu flowchart 46

Modem 54

Output Power 54

Push-to-Talk Delay 55

Radio Selection 61

Receive Frequency 54

Receive Level 58

Receive Pad 58

Receive Signal Strength 61

Repeater Mode 56

RX Timeout 56

S/N Ratio 61

selecting a main menu item 47

selection arrow 47

Serial Number 62

Set Date 60

Set Owner Message 60

Set Owner Name 59

Set Time 60

Show temperature and Voltages 62

Soft Carrier De-Key Delay 55

Software Revision 62

start-up screen 53

toggle between display-only and configuration modes 48

Transmit Frequency 53

Transmit Gain 58

Transmit Level 58

I-6 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

Transmit Timeout 55
Transmitter Status 62
Unit Address 57

using to set radio functions 48
Selection arrow 47
SER command (display radio serial number) 40
Serial Number screen 62
Set

active transceiver board (RADIO command) 38

active transceiver board (Radio Selection screen 61

audio receive level (Receive Level screen) 58

audio receive level (RXLEVEL command) 39

baud rate/format (Modem screen) 54

clear-to-send delay (Clear-to-Send Delay screen) 55

clear-to-send timer (CTS command) 32

communications attributes for data interface port (BAUD

command) 31
continuous key time-out (TOT command) 43
customer-programmable settings back to factory defaults

(INIT command) 35
date (Set Date screen) 60
intensity of LCD characters (Display Contrast screen) 59
internal modem speed (Modem screen) 54
keying mode (Continuous Keying screen) 56
keying mode (Key On Data screen) 57
key-on-data mode (DATAKEY command) 33
LCD background brightness (Background Intensity

screen) 59
LCD display to radio configuration mode (Access Level

screen) 53
major alarms (AMASK command) 30
minor alarm event classification (NMASK command) 36
output power (Output Power screen) 54
owner message (OWM command) 37
owner message (Set Owner Message screen) 60
owner name (OWN command) 37
owner name (Set Owner Name screen) 59
Pin 25 alarm output (ASENSE command) 31
push-to-talk delay (PTT command) 38
push-to-talk delay (Push-to-Talk Delay screen) 55
radio address (Unit Address screen) 57
radio as root or node (DTYPE command) 34
radio functions using front panel LCD 48
radio’s address (UNIT command) 44
receive frequency (Receive Frequency screen) 54
receive frequency (RX command) 39
receive time-out timer value (RXTOT command) 40
received data handling mode (BUFF command) 31
repeater mode (Repeater Mode screen) 56
RX timeout (RX Timeout screen) 56
soft carrier de-key delay (SCD command) 40
soft carrier de-key delay (Soft Carrier De-Key Delay

screen) 55
start of new message timer (DMGAP command) 34
time (Set Time screen) 60
time (TIME command) 43
transmit audio level (TXLEVEL command) 44
transmit frequency (Transmit Frequency screen) 53
transmit frequency (TX command) 43
transmit level (Transmit Level screen) 58
transmit timeout (Transmit Timeout screen) 55
transmitter state (Manual Key screen) 56

Set Date screen 60
Set Owner Message screen 60
Set Owner Name screen 59
Set Time screen 60

SHOW command (display various settings) 40
Show Temperature and Voltages screen 62
Simplex operation 5
SNR (Signal-to-Noise Ratio)

defined 8
display (S/N Ratio screen) 61

displaying (SNR command) 41
SNR, SNR! commands (display signal-to-noise ratio) 41
Soft Carrier De-Key Delay screen 55
Soft carrier de-key delay, set/display (Soft Carrier De-Key

Delay screen) 55

Software

display release information (SREV command) 41

upgrade internal (PROG command) 37
Software Revision screen 62
Specifications 72

data characteristics 72

primary power 73

receiver 73

transmitter 72
SREV command (display software release information) 41
Start-up 21
Start-up screen 53
Start-up screen, illustrated 23
STAT command (display alarm status). See also ALARM

command 41
STDBY LED 22
SWR (standing wave ratio), defined 8

T

Tables

alarm event codes 42
alarm relay connections 20
conventions used in PC command summary 25
data interface pinouts 18
dBm-watts-volts conversion 80
diagnostics, LCD screen commands 52
diagnostics, PC 27
diagnostics, PC commands 27
explanation of front panel LEDs 22, 64
feedline loss chart 11
hexadecimal values for major alarm conditions 29
hexadecimal values for minor alarm conditions 29
operating parameters, LCD screen commands 50
owner and radio information commands, PC 28
owner and radio information, LCD screen commands 52
PC commands--diagnostics 27
PC commands--owner and radio information 28
PC commands--radio operation 25
radio accessories 5
radio operation, PC commands 25

Technical reference 72–80

specifications 72
TEMP command (display internal temperature) 42
Temperature, display internal (TEMP command) 42
Testing. See Bench testing
TIME command (set/display time) 43
Timers

clear-to-send (CTS command) 32

clear-to-send delay (LCD screen) 55

continuous key time-out (TOT command) 43

push-to-talk (PTT command) 38

push-to-talk delay (LCD screen) 55

RX timeout (LCD screen) 56

soft carrier de-key delay (LCD screen) 55

MDS 05-3628A01, Rev. B MDS 4790M (MPT 1411) I/O Guide I-7

soft carrier de-key delay (SCD command) 40
start of new message (DMGAP command) 34
transmit timeout (LCD screen) 55

transmit timeout duration (LCD screen) 55
TOT command (set/display time-out timer ) 43
Transceiver board

assembly 67

display active (RADIO command) 38

removal, illustrated 67

removing or replacing 3, 67
Transmit

audio boost, enable/disable (Transmit Gain screen) 58

level, set/display (Transmit Level screen) 58

timeout value, display (Transmit Timeout screen) 55

timeout value, set (Transmit Timeout Duration screen) 55
Transmit Frequency screen 53
Transmit Gain screen 58
Transmit Level screen 58
Transmit Timeout Duration screen 55
Transmit Timeout screen 55
Transmitter

de-key (DKEY command). See also KEY command 33

specifications 72

state, set/display (Manual Key screen) 56
Transmitter Status screen 62
Troubleshooting

returning product for service. See inside rear cover
Troubleshooting. See Problem solving or Diagnostics
TX ALR LED 22
TX command (set/display transmit frequency 43
TXGAIN command (enable/disable transmit audio boost) 44
TXLEVEL command (set/display transmit audio level) 44

U

Unit Address screen 57
UNIT command (set/display radio’s address) 44
Up/down arrow buttons 47

use in radio configuration 48

V

Voice communications 19
Volts, conversion to dBm or watts, table 80

W

Watts

conversion to dBm or volts, table 80
Windows PC. See PC 23
Wiring interface, connections 17

I-8 MDS 4790M (MPT 1411) I/O Guide MDS 05-3628A01, Rev. B

IN CASE OF DIFFICULTY...

GE MDS products are designed for long life and trouble-free operation. However, this equipment, as with
all electronic equipment may have an occasional component failure. The following information will assist
you in the event that servicing becomes necessary.

FACTORY TECHNICAL ASSISTANCE

Technical assistance for our products is available from our Customer Support Team during business hours
(8:00 A.M.–5:30 P.M. Eastern Time). When calling, please give the complete model number of the radio,
along with a description of the trouble symptom(s) that you are experiencing. In many cases, problems can
be resolved over the telephone, without the need for returning the unit to the factory.

Please use the following telephone numbers for product assistance:
585-242-9600 (Phone)
585-242-9620 (FAX)

FACTORY REPAIRS

Component-level repair of radio equipment is not recommended in the field. Many components are
installed using surface mount technology, which requires specialized training and equipment for proper
servicing. For this reason, the equipment should be returned to the factory for any PC board repairs. The
factory is best equipped to diagnose, repair and align your radio to its proper operating specifications.

If return of the equipment is necessary, you will be issued a Returned Material Authorization (RMA)
number. The RMA number will help expedite the repair so that the equipment can be repaired and returned
to you as quickly as possible. Please be sure to include the RMA number on the outside of the shipping
box, and on any correspondence relating to the repair. No equipment will be accepted for repair without

an RMA number.

A statement should accompany the radio describing, in detail, the trouble symptom(s), and a description
of any associated equipment normally connected to the radio. It is also important to include the name and
telephone number of a person in your organization who can be contacted if additional information is
required.

The radio must be properly packed for return to the factory. The original shipping container and p ackaging
materials should be used whenever possible. All factory returns should be addressed to:

GE MDS, LLC
Customer Service Department
(RMA No. XXXX)
175 Science Parkway
Rochester, NY 14620 USA

When repairs have been completed, the equipment will be returned to you by the same shipping method
used to send it to the factory. Please specify if you wish to make different shipping arrangements.

GE MDS, LLC
175 Science Parkway
Rochester, NY 14620

General Business: [phone]

FAX: [phone]

Web: www.GEmds.com