Mitsubishi ST200, ST211, ST221M, ST251 Technical Manual
ST200TSM02
ST200 Series
(ST211, ST221M & ST251)
Satellite Communication Systems
Technical Support Manual
Mitsubishi Electronics America, Inc.
Mitsubishi Electronics America, Inc.
Specifications and information within this document are subject to change without prior notice.
All rights reserved.
MITSUBISHI ELECTRONICS AMERICA, INC.
1.0 Introduction ............................................................................................................................................................1
2.0 System Overview....................................................................................................................................................1
2.1 Satellite Segment................................................................................................................................................1
2.2 Communications Ground Segment.....................................................................................................................2
2.3 Mobile Terminal Segment..................................................................................................................................3
3.0 Product Overview....................................................................................................................................................3
3.1 General Overview...............................................................................................................................................3
3.2 Key Features.......................................................................................................................................................5
3.3 Product Positioning.............................................................................................................................................5
3.3.1 Target Markets.............................................................................................................................................5
3.3.2 Applications.................................................................................................................................................6
4.0 Product Description.................................................................................................................................................7
4.1 General ...............................................................................................................................................................7
4.2 Antenna Units.....................................................................................................................................................9
4.2.1 Dome Antenna Unit.....................................................................................................................................9
4.2.2 Fixed Site Antenna Unit ..............................................................................................................................9
4.3 Common Transceiver Unit..................................................................................................................................9
4.4 CTU Cradle and Junction Box..........................................................................................................................10
4.5 Beam Steering Unit...........................................................................................................................................11
4.6 CTU Power Components..................................................................................................................................11
4.7 OmniQuest® Description.................................................................................................................................11
4.8 Basic Handset...................................................................................................................................................15
4.9 Push-to-Talk Handset.......................................................................................................................................16
4.10 Other Accessories........................................................................................................................................17
5.0 Product Operation.................................................................................................................................................17
5.1 Design Overview..............................................................................................................................................17
5.2 Signaling and Communications Channels........................................................................................................18
5.2.1 Pilot Signal ................................................................................................................................................18
5.2.2 GC-S Channel............................................................................................................................................18
5.2.3 MET-ST Channel.......................................................................................................................................19
5.2.4 MET-SR Channel......................................................................................................................................19
5.2.5 MET-C Channel.........................................................................................................................................19
5.2.6 FES-C Channel..........................................................................................................................................19
5.3 Modulation & Encoding...................................................................................................................................20
5.4 Signal Processing..............................................................................................................................................20
5.4.1 Scrambling.................................................................................................................................................20
5.4.2 Interleaving................................................................................................................................................21
5.4.3 Forward Error Correction..........................................................................................................................21
5.5 Security Functions............................................................................................................................................21
5.5.1 Electronic Features....................................................................................................................................21
5.5.2 Authentication............................................................................................................................................22
5.5.3 Scrambling.................................................................................................................................................22
5.6 Network Data Distribution & Storage..............................................................................................................22
5.7 Shutdown Conditions........................................................................................................................................22
5.8 Operation..........................................................................................................................................................23
5.8.1 Initialization...............................................................................................................................................23
5.8.2 OmniQuest® Setup .......................................................................................................... ....................24
5.8.3 Placing a Telephone Call...........................................................................................................................24
5.8.4 Receiving a Telephone Call.......................................................................................................................24
5.8.5 Data Communication.................................................................................................................................24
5.8.6 Net Radio/Dispatch Operation...................................................................................................................26
5.9 Possible Cable Extensions................................................................................................................................26
5.10 Multiple Handsets...........................................................................................................................................27
5.11 Other Operational Considerations...................................................................................................................27
6.0 Installation............................................................................................................................................................29
6.1 Fixed Site (ST221M)........................................................................................................................................30
6.1.1 Occupant and Site Safety...........................................................................................................................30
6.1.2 General Installation Standards...................................................................................................................31
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6.1.3 Installation Planning..................................................................................................................................32
6.1.4 Antenna Unit..............................................................................................................................................34
6.1.5 Transceiver ................................................................................................................................................35
6.1.6 Power Connection......................................................................................................................................37
6.1.7 Cable Runs.................................................................................................................................................38
6.1.8 Junction Box..............................................................................................................................................39
6.1.9 Handsets and Accessories..........................................................................................................................40
6.2 Land Mobile (ST211).......................................................................................................................................42
6.2.1 Occupant and Vehicle Safety.....................................................................................................................42
6.2.2 General Installation Standards...................................................................................................................44
6.2.3 Installation Planning..................................................................................................................................45
6.2.4 Dome Antenna Unit...................................................................................................................................49
6.2.5 Transceiver ................................................................................................................................................50
6.2.6 Power Connection......................................................................................................................................54
6.2.7 Junction Box..............................................................................................................................................55
6.2.8 Handsets and Accessories..........................................................................................................................55
6.2.9 Beam Steering Unit....................................................................................................................................56
6.2.10 Horn Alert................................................................................................................................................57
7.0 Programming & Commissioning..........................................................................................................................58
7.1 General Process and Procedures.......................................................................................................................58
7.2 Initialization......................................................................................................................................................59
7.3 Number Assignment Module (NAM) Programming........................................................................................60
7.4 Manual Pilot/GC-S Selection............................................................................................................................63
7.5 Commissioning .................................................................................................................................................65
7.6 Commissioning Problems.................................................................................................................................66
7.7 Other Procedures ..............................................................................................................................................67
7.7.1 Reactivation...............................................................................................................................................67
7.7.2 Re-commissioning.....................................................................................................................................68
8.0 Product Support....................................................................................................................................................69
8.1 Product Distribution..........................................................................................................................................69
8.2 Marketing & Sales Support...............................................................................................................................69
8.3 Technical Support.............................................................................................................................................69
8.4 Limited Warranty..............................................................................................................................................70
8.4.1 Limited Warranty Terms...........................................................................................................................70
8.4.2 Mitsubishi Limited Warranty Statement....................................................................................................72
8.4.3 Limited Warranty Administration..............................................................................................................74
8.5 Out-Of-Warranty Repairs.................................................................................................................................74
9.0 Problem Resolution ..............................................................................................................................................75
9.1 First Line Problem Analysis.............................................................................................................................78
9.2 Trouble Checklists............................................................................................................................................80
10.0 Key Contact Directory........................................................................................................................................85
11.0 System Specifications.........................................................................................................................................87
GLOSSARY................................................................................................................................................................90
APPENDIX A - STATUS MONITOR REFERENCE................................................................................................92
APPENDIX B - INITIALIZATION AND COMMISSIONING PROCEDURES......................................................94
APPENDIX D - DATA OPERATION......................................................................................................................100
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1.0 Introduction
This manual provides the basic information require d to success fully sell, distribute, and m aintain
the Mitsubishi ST200 Series satellite terminals. The ST200 Series include the following
configurations:
• ST211 land mobile
• ST221M fixed site
• ST251 OmniQuest® transportable
This document, ST200TSM02, replaces all Technical Support Manuals previousl y published by
Mitsubishi Electronics America, Inc. (MELA) as it combines and updates the contents of the
ST200TSM01 and the ST251TSM01 into one comprehensive manual.
Distributors and other sales/service agents should use this reference document for trainin g staff
and addressing typical questions and problems from the field. Two portions of this manual
warrant special attention: Sections 8.0 and 9.0. The first details MELA’s product support
policies and procedures. The second describes key operational considerations that can prove
useful in addressing frequently asked questions. This manual is posted on MELA’s web site
(www.melamsat.com) in PDF format. Distributors are encouraged to download, print and
distribute copies to all personnel involved in the MSAT business.
For consistency with previous manuals and concise notation this document uses the terms
Mobile Terminal (MT), Mobile Earth Terminal (MET), satellite terminal, satellite
communications system and satellite telephone interchangeably.
2.0 System Overview
The Mitsubishi mobile satellite telephone products are designed to work on the MSAT (L-Band)
satellite system anywhere in North and Central America including Alaska, Hawaii, the
Caribbean, and 200 miles of coastal waters. There are currently three satellite network
providers: American Mobile (AMSC) located in Reston, Virginia, TMI Communications Ltd.,
located in Ottawa, Canada and Telecomunicaciones De Mexico (Telecom), located in Mexico
City, Mexico. The Mitsubishi MSAT products addressed in this manual are sold and distributed
in North and Central America by authorized distributors and resellers.
The MSAT system comprises a satellite segment, communications ground segment (CGS) and a
mobile terminal segment.
2.1 Satellite Segment
The satellite segment acts as a relay site, similar to a cellular communications base station. It
passes signals to and from the CGS and MTs. AMSC launched its satellite (AMSC-1) into
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geosynchronous orbit (~ 22,300 miles / 36,000 km altitude). The MSAT satellite is one of the
most powerful communications satellites on-orbit (>500,000 Watts) and is capable of seamless
North American and Central American coverage. Hughes Communications designed the MSAT
satellite with relatively large antennas, allowing for relatively small MT antennas.
2.2 Communications Ground Segment
The CGS routes all MT calls and provides the interface to the Public Switched Telephone
Network (PSTN). The ground segment also provides feeder communications to the satellite,
establishes channels for end-user calls, and managing system resources. AMSC’s CGS is
located at AMSC headquarters in Reston, Virginia with a backup facility located 26 miles south
of this location. TMI’s CGS is located in Ottawa, Ontario and Telecom’s CGS is located in
Mexico City.
CGS subsystems include the Feederlink Earth Station (FES), Network Communication
Controller (NCC), and Network Operations Center (NOC). The FES links the signaling channels
between the satellite and the NCC and communications channels between the satellite and the
PSTN. The NCC uses these signaling channels to manage all communication s ystem resources
through a variable number of Control Groups (CG). Each control group uses specific signaling
channels for specific MTs. The NOC oversees the entire operation, including billing and
customer service.
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To Satellite
Communications Ground Segment (CGS)
NCC FES
NOC
PSTN
2.3 Mobile Terminal Segment
As end-user equipment, MTs transmit and receive signals to and from the CGS via the satellite.
MSAT terminals include land mobile, transportable, fixed, maritime, and aeronautical
applications. Each Mitsubishi MT comprises three functional units: Antenna Unit (AU),
Transceiver Unit (TU), and one or more user interfaces (like handsets or a personal computer).
3.0 Product Overview
3.1 General Overview
The ST211 terminal includes a transceiver, beam steering unit, and handset or user terminal
options. The beam steering unit is a small gyroscope that determines vehicle motion for mobile
satellite tracking.
The ST221M fixed site terminal comprises the same major components as the land mobile
configuration, minus the beam steering unit. The parabolic antenna in this high gain
configuration replaces the dome type antenna in the land mobile unit. The ST221M also
includes an AC/DC power supply.
Standard items and optional accessories provide basic digital voice, wide area dispatch and data
capabilities. Mitsubishi land mobile and fixed site antennas physically incorporate the radio
frequency electronics, easing installation and troubleshooting. The following figures show the
primary elements of the ST211 and ST221M configurations respectively.
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ST211
ST221M
The ST251 OmniQuest® transportable terminal is one of the most versatile satellite
communications systems available to date offering many unique features and capabilities.
OmniQuest® is an integrated portable terminal containing the transceiver, antenna, battery and
handset as depicted below.
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3.2 Key Features
All Mitsubishi MTs are easy to operate. The basic handset, for point-to-point calling, looks and
operates like a cellular phone. There are three one-touch speed dial keys and 99 alphanumeric
memory locations. The handset permits any key answering, displays received signal strength,
and lets users enable special features from a menu of functions. Optional accessories also allow
users to operate in a hands-free mode.
All MTs accommodate service offering for wide area dispatch with an optional push-to-talk
handset (shown above) and circuit switched data at 4800 bits per second.
Three new features have been added to these second-generation MTs: Horn Alert, Auto-PowerOn and Echo Cancellation. Horn Alert is ideal for those with Land Mobile applications who
need to be able to hear the MT ringing while away from their vehicle but while still nearby.
Auto-Power-On allows the user to set the MT to automatically power on once the vehicle’s
engine is started (just like a car radio when left on). The software–based echo cancellation
feature allows users to avoid having to install an echo canceler board in the TU.
3.3 Product Positioning
The mobile, fixed and portable terminals deliver communication where there is no existing
infrastructure; or when other systems fail or become overloaded. These MTs do not compete
with terrestrial offerings like cellular or PCS. However, for those companies and industries that
need seamless communication, Mitsubishi MTs are a viable solution. Seamless coverage and a
flat airtime rate are important for prospects who operate in multiple locations on an on-going
basis.
These MTs offer top-notch brand name recognition, reliability, and quality that Mitsubishi
supports with an in-warranty replacement program.
3.3.1 Target Markets
Mitsubishi mobile, fixed and portable configurations effectively address several niche markets:
♦ Industries that operate expansive networks like telecommunications, energy, and
utilities can more efficiently manage their field units with Mitsubishi land mobile
terminals.
♦ Remote site industries, like those involved in construction or natural resource
extraction, can employ Mitsubishi fixed site MTs for communicating with isolated
management or operation centers. This market also extends to the tourist industry
with remote hunting and fishing lodges.
♦ All configurations also address large corporations or institutions—that because of
geography or regulation—require back-up or contingency communications.
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Companies in California and Florida in the US and other locations throughout Canada
and Central America are especially receptive to this concept. Further, companies
involved in transporting or working with hazardous materials like nuclear power
generation and HAZMAT transportation must have an emergency mode of
communications.
3.3.2 Applications
Specific MSAT applications for land mobile, fixed site and portable MTs exist throughout North
and Central America today. The following examples may provide some additional insight for
sales and marketing forces. The list is not exhaustive:
♦ Telecommunications companies have pur chased land mobile and transportable MTs
for operating and maintaining land lines, both fiber optic and wire. Mitsubishi MTs
can improve the efficiency of field units responding to fiber optic cable failure, saving
a lot of money. These companies typically use dispatch service.
♦ Oil and gas companies use land mobile MTs for regular pipeline maintenance
operations. Maintenance trucks testing pressures and physical integrity throughout
the extent of a pipeline or segment of pipeline can remain in constant
communications. This concept is very similar to that employed in the
telecommunication industry.
♦ Mining and construction companies can more effectively conduct day-to-day
business from even the most remote locations. Their business may require continuous
communications with other remote sites, fleets on the road, and headquarters through
the PSTN. Day-to-day business may just entail a report at the end of each day—
either voice or data.
♦ Any large corporation in regions prone to natural disasters, like the West Coast or
Gulf States, can use MTs for contingency communications. This application is not
the same as back-up communications for conducting business operations. Rather,
contingency communications link key executives and decision-makers for
implementing already existing recovery and response plans.
♦ Hospitals, nuclear facilities, and HAZMAT trucks require some form of
emergency communications for public safety reasons. Dedicated channels or high
availability channels can save lives during emergency situations that can disable or
degrade the existing terrestrial infrastructure. As a simple example, any cellular
telephone user in a major metropolitan area knows that even a minor traffic accident
on a commuter route can saturate capacity as hurried drivers begin making calls.
More severe emergencies exponentially degrade consumer-type systems.
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4.0 Product Description
4.1 General
The land mobile MT consists of a Common Transceiver Unit (CTU), a medium gain antenna,
handset, cradle and junction box (J-box), Beam Steering Unit (BSU) and all required cabling.
The fixed site configuration also includes a CTU, handset, parabolic antenna, AC/DC power
converter, all required cabling, cradle, and junction box. The ST221M standard kit includes a 50
foot (15 meter) CTU to AU cable set. Other cable options might be available through certain
distributors.
The OmniQuest® ST251 is a complete communications terminal containing a Trans ceiver Unit
(TU), Antenna Unit (AU), Handset, Battery and an AC Adapter/Charger. The antenna unit is
conveniently mounted in the notebook lid providing a very efficient design that allows for quick
and easy setup. All standard equipment fits in the soft carrying case provided with OmniQuest®.
Optional accessories are available for all terminals for added functions and capability. Widearea or digital dispatch requires an optional Push-To-Talk (PTT) handset. Note: availability of
system features may vary based on service provider offerings. The following tables summarize
standard and optional MT components, respectively.
Standard ST211 Land Mobile MT Components
Part Number Description
TU200A CTU, Mounting Kit
AU201A AU, Mounting Kit, 18’ (5.5m) AU-TU Cable
AU1200A(S) BSU, Mounting Kit
SZ130A Cradle-3, Junction Box, Mounting Kit
SZ460A 20’ (6m) Power Cable
SZ100A Basic Handset
ST200N02 Owner’s Manual
Standard ST221M Fixed Site MT Components
Part Number Description
TU200A CTU, Mounting Kit
AU601B AU, Mounting Kit
SZ130A Cradle-3, Junction Box, Mounting Kit
PUP-55-13-J9 AC/DC Converter
FSC50 50’ (15m) AU-TU Cable Kit
SZ100A Basic Handset
ST200N02 Owner’s Manual
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Standard ST251 MT Components
Part Number Description
NT100A Base Unit (includes integrated antenna, antenna electronics and
removable transceiver unit)
SZ100A Handset w/ Curl Cord
OQ-CRADLE Cradle
SZ511A NiMH Battery Pack
SZ503A AC Adapter/Charger
ME-SN Carrying Case
ME-COM Compass
OQ-REF1 Quick Reference Card
ST251NO1 Operating Instructions
Optional Components
Part Number Description
SZ300A PTT Handset; for wide-area dispatch
FZ1283A Monitoring Speaker; for hands free operation
FZ806A External Microphone; for hands free operation
OQFAU50 Fixed Dish Antenna w/50 ft cable for OmniQuest fixed site use
OQFAU100 Fixed Dish Antenna w/100 ft cable for OmniQuest fixed site use
SZ351A Junction Box for wide-area dispatch w/OmniQuest
SZ601A Cigarette Lighter Adapter for OmniQuest
SZ511A Additional Battery for OmniQuest
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4.2 Antenna Units
4.2.1 Dome Antenna Unit
The Dome AU (AU201A) contains a single helical antenna element mounted on a ground plane
which is fixed in elevation angle and mechanically steerable in azimuth. The AU201A houses
the RF Electronics Unit (RFU) underneath the antenna. The RFU includes a high power
amplifier, low noise amplifier, diplexer, and control electronics. The antenna gain is
approximately 9 dBi, with nominally 20 Watts of L-Band RF energy (~1.6 GHz). The Dome
AU receives steering commands from the BSU, through the CTU.
WARNING: Stay 6 inches (15 cm) away from the antenna while transmitting
!
NOTE: The AU antenna cable connection at the CTU must be firmly secure prior to operation.
Loose or improper connection may render the terminal inoperable (not able to power
on) or result in error messages.
4.2.2 Fixed Site Antenna Unit
The Fixed Site AU (AU601B) is a parabolic antenna (with feed horn) which physically
incorporates the RFU, including high power amplifier, low noise amplifier, and diplexer. The
AU601B provides a gain of approximately 20 dBi and nominally emits 20 Watts in L-Band (~1.6
GHz).
WARNING: Stay 26 inches (60 cm) away from the antenna while transmitting
!
NOTE: The AU cable connections at the antenna and at the CTU must be firm l y secure prior to
operation. Loose or improper connections may render the terminal inoperable (not able
to power on) or result in error messages.
4.3 Common Transceiver Unit
The land mobile and fixed site MTs utilize a Common Transceiver Unit (CTU), the TU200A,
which provides interfaces for AUs, handsets and data devices, as well as managing signaling and
communications with the CGS via the satellite. The CTU demodulates and processes received
antenna signals; process, modulate, and send outgoing signals to the antenna for transmission;
and manages all handsets, data devices and other accessories.
In addition to providing the major MT interfaces, the CTU is comprised of a main board,
converter board and necessary power supplies. The main board multiplexes, scrambles, en codes,
and interleaves signals in addition to providing frame-formatting functions. Its logic and
signaling subsystem provides the central control of the MT to initialize self tests, setup/configure
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the CTU, handle protocols, and manage control signals and messages with handset(s) and data
devices. A logic and signaling processor in the main board includes a CODEC for anal og and
digital conversions of voice signals. The CTU converter board contains the necessary frequency
synthesizers, up and down converters, and the QPSK modulator.
The most current CTU configuration accommodates 4800 bits per second data communications,
a satellite acquisition algorithm that speeds network access, and advanced service features. The
availability of advanced service features depends on the specific offerings of each service
provider, but can include:
♦ Call Line Identification (Caller ID) and Caller ID Restriction—Handset displays
the caller’s phone number or protects your phone number from such devices
♦ Connected Line Identification and Connected Line Restriction —Handset displays
the phone number of the party who you called or protects your phone number
from such display
♦ Call Transfer—Transfers a call in progress to a third party without any previous
connection
♦ Call Forwarding and Voice Mail—Forwards incoming calls to another number
(without ringing) or to a voice mailbox when your phone is busy or unattended
♦ Call Waiting—Notifies the user of an incoming call during a conversation and
allows switching between these calls
♦ Conference Calling—Allows conversations with several parties simultaneously
♦ Call Barring—Restricts placing one or more types of calls
♦ Alternate Account Charging—Allows billing to specific accounts for particular
phone calls
♦ Enhanced Fraud Protection—Requires a four digit PIN, that the service provider
assigns, to complete dialing
4.4 CTU Cradle and Junction Box
The cradle and junction box provide the appropriate interfaces for the basic handset and
accessories with the CTU. The handset cradle package (SZ130A) includes a clip mount with an
RJ-45 handset interface and the junction box (SZ350A) interface for accessories (PTT handset,
monitoring speaker, and hands free microphone).
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NOTE: All connections between the basic handset and the CTU must be firmly secure. Loose
or improper connections may render the terminal inoperable (not able to power on) or
result in error messages.
4.5 Beam Steering Unit
The Beam Steering Unit, or BSU (AU1200A), is a small component that attaches to the side of a
CTU in the land mobile configuration. Its piezo-electric gyroscope and control system sense
changes in vehicle direction. The BSU feeds these measurements directl y through the CTU to
the antenna for closed loop tracking. The CTU also processes this information for optimizing its
system management functions. Section 5 includes additional information on antenna pointing.
The BSU must be mounted within + 5o of vertical (relative to the ground) for proper operation.
For rapid satellite acquisition and lock, the vehicle should remain stationary or move along a
straight path for the first ten (10) seconds of MT operation.
4.6 CTU Power Components
The power cable (SZ460A) connects from a vehicle’s 12 Volt battery line directly to the CTU in
a land mobile configuration. The power cable has a +12V power line, a +12V ignition sense
line, and a ground line. The power and ignition sense lines each contain a 10A in-line fuse
which protects the CTU and the vehicle’s electrical system.
The PUP-55-13-J9 AC/DC converter provides 13.8 V at 55 Watts of continuous output power to
the fixed site ST221M. This unit is enclosed in a polycarbonate case with an IEC320 inlet
connector, which allows interchangeable power cords for international use. All models meet
VDE class B and FCC class B emissions limits, and are approved to UL, CSA, and CTUV safety
standards.
4.7 OmniQuest® Description
A brief description of each of the main components of OmniQuest
®
is provided below.
4.7.1 Base Unit
The OmniQuest
®
Base Unit (NT100A) houses all of the main electronics of the system including
the Antenna, Radio Frequency Unit (RFU), removable Transceiver Unit (TU), and power
electronics (including internal battery). Latches are included to secure the antenna and TU and a
release lever secures the battery pack when the door is open.
NOTE: The TU and the battery are the only removable sub-assembli es in the OmniQuest®. The
electronics contained in the RFU (within the NT100A unit), the antenna lid and the
TU201A subassemblies are not serviceable outside MELA’s service center.
Distributors and their agents should not attempt to access these electronics unless
authorized by MELA (does not apply to Battery Pack).
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4.7.1.1 Antenna
MITSUBISHI ELECTRONICS AMERICA, INC.
The integrated lid Antenna receives signals transmitted from the satellite and transmits signals
provided from the RFU. The OmniQuest
patch antenna integrated into the lid and connected to the OmniQuest
®
Antenna is comprised of a two element planar array
®
Base Unit. The antenna
provides a gain of approximately 10.8 dBic and emits 20 Watts of RF energy nominally in the L
Band frequency range (~1.6 GHz).
WARNING: Stay 2 feet (24”) / 61 cm away from the antenna while transmitting
!
The OmniQuest
®
antenna must be manually pointed at the satellite which is aided by using the
Quick Reference Card and compass provided in the standard carrying case. Because the
beamwidth of the antenna is fairly wide (~30o), approximate pointing of the antenna is easy.
Once the approximate location of the satellite has been established, the pointing angle can be fine
tuned by using the Received Signal Strength Indicator (RSSI) displayed on the Handset (i.e.,
approximate or initial pointing of the satellite needs only to be accurate enough so that a signal
can received on the RSSI). See section 5.11 for operational considerations concerning the RSS I
and OmniQuest
®
setup.
NOTE: If an approved external antenna is used, the cable must be securely attached to the
RFU prior to operation. Likewise, if switching from an external antenna back to the
OmniQuest
®
self-contained antenna, the antenna cable must also be securely at tached.
Loose or improper connections may render the terminal inoperable (not able to power
on or low received signal) or result in error messages.
4.7.1.2 RF Unit
The RFU is contained within the Base Unit and provides an interface between the Omni Quest
antenna and the removable TU. The RFU contains a High Power Amplifier (HPA), Low Noise
Amplifier (LNA), diplexer, and control electronics that provide the proper amplification,
filtering, and control of the RF signals generated from the TU and received from the satellite
through the antenna.
4.7.1.3 Transceiver Unit
The removable TU201A Transceiver Unit is located inside the Base Unit, providing the
necessary interfaces for user devices and the RFU, as well as managing all signaling and
communications with the CGS via the satellite. It demodulates and processes the signals
received by the antenna through the RFU; processes, modulates, and sends signals to the RFU
for transmission, and manages all interfaces with user interface equipment, other connected
accessories, and network interfaces with the CGS.
NOTE: All required interfaces for the OmniQuest
®
Transceiver Unit are available on the TU
connector panel. Distributors should not attempt to access the electronics inside the
Base Unit without prior authorization from MELA.
®
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NOTE: The connection of the TU to either the Base Unit or the TMU must be firmly secure.
To ensure proper connections after inserting the TU into the Base Unit, adjust latches
(located on BOTH sides of the Base Unit) to the “L” or locked position.
4.7.2 Battery Pack
The SZ511A Battery Pack provides DC voltage for operating the OmniQuest® MT. The Battery
Pack is comprised of NiMH Battery cells (similar to some cellular telephones) and provides for
the storage of energy to provide DC powe r (see speci fic ati ons for rat ings). T he Battery Pack can
be charged through use of the AC Adapter/Charger from an ex ternal 115 VAC / 60 Hz power
source while installed in the OmniQuest® Base Unit or when removed as discussed below.
NOTE: There are several handling, storage, and charging considerations for increasing the
performance and lifetime of NiMH Battery Packs. Please refer to the ST251 Operating
Instructions for details.
NOTE: The standard Battery Pack is rated to provide for > 1 hour of talk time at 77oF / 25oC.
Because the MT is voice activated, the typical conversation time obtained from a fully
charged Battery Pack could be > 2 hours.
NOTE: There are several operational considerations concerning batter y run time, which should
be well understood by the users. Please refer to the ST251 Operating Instructions or
section 5.11 for details.
NOTE: This Battery Pack has been designed specifically for use and operation with the
OmniQuest® ST251 MT. Do not attempt to use other batteries with this unit.
4.7.3 OmniQuest®AC Adapter/Charger
The SZ503A AC Adapter/Charger provides two methods for charging the Battery Pack as well
as providing DC power output for operations. The DC output cable of the AC Adapter/Charger
can be used for trickle charging a battery pack installed in the OmniQuest® MT and/or for
powering the MT during operation when connected to the DC Input Connector of the MT.
Alternately, the Battery pack can be removed from the MT and attached directly to the unit for
charging. Rapid charging of the battery takes approximatel y 2 hours. When the MT is powered
on and in transmit mode, rapid charging changes to trickle charging and may take up to 24 hours
if the MT is continuously transmitting (e.g., in data mode).
NOTE: When the battery pack is fully charged, the indicator light on the SZ503A will change
from red to green (for either the “spa re” batter y pack or the “main” b attery pack i nside
the base unit). Prompt removal of the battery is required to avoid overcharging, and
potential damage to the SZ511A battery pack.
The DC output cable of the SZ503A is approximately 1 foot (32 cm) in length and is hard wired
directly to the AC Adapter/Charger. The plug at the end of the DC output cable is a special 4-pin
connector which mates to the DC Input connector of the Base Unit. The AC input cable for the
AC Adapter/Charger is approximately 6 feet (1.8 m) in length. The c ylindrical objects attached
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to the cords are special inductive filters and are required to maintain compliance with FCC
requirements for conducted emissions. No attempt should be made by distributors or users to
fabricate replacement or alt ernate cables, to modify the length of these cabl es, or to remove or
change the filters on the cables.
NOTE: The AC Adapter/Charger has been designed specifically for the OmniQuest® ST251.
Only this unit should be used to provide power to the MT for operation or to charge the
Battery Pack from an AC power source.
4.7.4 Standard Carrying Case
The Standard Carrying Case provides space to accommodate all of the standard components of
the OmniQuest®, and AC Adapter/Charger. Also provided with the Standard Carrying Case is a
magnetic compass and a Quick Reference Card to assist in setup. The Standard Carrying Case is
constructed of 600 denier nylon with reinforced seams.
NOTE: The Standard Carrying Case only provides light protection to the OmniQuest
components from moisture and impact. The user is responsible for ensuring that the
OmniQuest® components are protected to a level consistent with the users specific
operating and transportation environment.
4.7.5 OmniQuest® Cigarette Lighter Adapter (CLA)
The SZ601A Cigarette Lighter Adapter (CLA) provides a method to supply 9.6V DC input to the
MT from a standard 12V vehicle cigarette lighter socket. The CLA cables are similar in length
to the AC Adapter/Charger cables. The CLA is functionally equivalent to the AC
Adapter/Charger and can both power the OmniQuest® unit and charge a battery while installed in
the OmniQuest® unit or when installed on top of the charger.
NOTE: The SZ601A CLA has been designed to meet the specific voltage requirements of the
OmniQuestTM ST251. Only the SZ601A should be used to provide power to the MT for
operation or to charge the SZ511A Battery Pack from a standard cigarette lighter
socket. Use of other CLA adapters may void the ST251 limited warranty.
4.7.6 OmniQuest® Junction Box
Only OmniQuest® specific Junction Boxes (SZ351A, SZ352A) are designed to work with the
ST251 terminal. Both Junction Boxes provide the capability of using the PTT Microphone and
allow the use of hands-free accessories (i.e. external speaker, microphone). The SZ352A
Junction Box includes a longer cable and is therefore more suitable for permanent vehicle
installations or if the customer desires a longer cable. The Junction Box connects to the “J-Box”
port of the OmniQuest® TU. For hands-free operation, the user connects the hands-free
microphone and speaker to the junction box.
®
NOTE: Although the handset contains an external speaker which will provide hands-
free/dispatch audio, the external speaker is a desirable and highly recommended option
if the handset speaker is not loud enough or a remote location of the speaker is desired.
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In most cases, the customer will prefer the external speaker for dispatch and hands-free
operation. To activate hands-free mode, the handset must be connected to the TU and securely
latched into the handset cradle. The handset cradle contains a magnet that deactivates the
handset speaker and activates the external speaker when connected to the Junction Box.
4.7.7 OmniQuest® Fixed Dish Antenna
External antenna
18”
(OQFAU) shown with
100’ cable (Type
LMR400) and
optional tripod.
Weight of ant enna
and mounting
hardware is
less than 5 lbs.
See Appendix C for
detailed installation
instructions.
OmniQuest® is capable of being operated with an external Fixed Dish Antenna (OQFAU50)
connected to the RFU through the external ant enna port (located on th e back of the OmniQuest
base unit). The Fixed Dish Antenna is 18” in diameter and comes with mounting hardware and
50 feet of cable (LMR240). A 100’ cable may also be used and is commercially available. The
cable type needed is LMR400 and requires SMA straight connectors. The OQFAU50 is fully
weatherproof and “marinized” for use in harsh or salt water environments. For temporary fixedsite applications, use of a tripod is desirable, however, the OQFAU50’s mounting b racket will
also accommodate a 2” diameter mounting pole.
4.8 Basic Handset
The standard handset (SZ100A) operates as a control panel for dialing and storing phone
numbers and accessing built-in functions. The handset has a two line, seven character liquid
crystal display (LCD) and a 23 button keypad (illuminated). The keypad control panel has a
standard 12 button alpha-numeric telephone keypad (most with multiple functions), 3 speed
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®
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dialing keys, and eight other unique keys including a power button and two volume control
buttons on the side of the handset. Users can input up to 28 characters or numbers for placing a
call or memory storage in one of 99 locations (two screens required to see the entire location).
The interface between the standard handset and the cradle is a special 8-wire interface using RJ45 connections. The interface consists of three audio lines, two serial data lines, a power-on
signal line, +12V DC power, and ground. The serial data lines transmit keypad strokes and
receive and display commands from the handset and CTU.
The curl cord stretches to a maximum length a 5 feet (1.5m). Do not attempt to fabricate a
replacement or alternate cable, or modify the length of the curl cord provided. Although
standard RJ-45 extension cables exist, Mitsubishi Electronics does not endorse these extension
cables or guarantee MT product performance and reliability with these cables.
The connection of the Handset curl cord at the cradle must be firmly secure. Loose or improper
connections may render the terminal inoperable (not able to power on) or result in error
messages.
4.9 Push-to-Talk Handset
The Push-To-Talk handset, or PTT microphone, is an optional accessory providing access to the
wide-area dispatch service known as net radio. The PTT handset lets users select up to 15
different networks, or talkgroups. The MSAT service provider configures these channels, which
operate in a half-duplex manner like a standard two-way radio. The PTT handset also allows
users to automatically scan through configured talk groups and select active networks. The PTT
handset plugs into the junction box with the optional external speaker (needed for received
audio).
The interface between the PTT handset and the junction box is a special 8-wire interface using
RJ-45 connections. The interface comprises one audio line, two serial data lines, a PTT signal
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line, a power-on signal line, +12V DC power, and ground. The serial data lines transmit keypad
strokes and display commands to/from the transceiver.
The PTT handset must be securely connected to the junction box prior to power-on of the MT.
Net radio operation also requires an external monitoring speaker.
4.10 Other Accessories
Other accessories such as Mitsubishi hands free microphones and ex ternal speak ers a re available
through equipment distributors. Customers should contact these distributors directly concerning
cost and availability.
5.0 Product Operation
Mitsubishi satellite telephones are user friendly, operating like a cellular phone (i.e., no dial tone)
and requiring minimal user interaction. These MTs have many built-in features including special
function keys, user programmability options, and security features. This section includes a brief
design overview as useful background for understanding MT operations.
5.1 Design Overview
The Mitsubishi MTs operate under a blanket license from the FCC for MSAT Service under Part
25 (Satellite Communications) of its rules. This license, on file with the FCC (File No. 2823DSE-P/L-93), does not require special MT identification tags for compliance. The fixed site
MT, ST221M, also complies with Part 15 of the FCC Rules as a Class B unintentional source of
radiation subject to the conditions thereunder. The land mobile MT has no requirement for Part
15 compliance.
The MSAT network operates in the L-Band of the frequency spectrum, roughly covering 1.5-1.6
GHz. Because L-Band signals are subject to fading, Mitsubishi MT design includes additional
margin to assure performance and reliability. The terminals’ digital modulation and signal
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processing techniques also minimize fading effects to a level that outperforms analog cellular
and standard two-way radio systems.
The mean time between failures for the land mobile and fixed site MTs is greater than 5200
hours of continuous use—actual performance may exceed this design value.
: WARNING: MT operation may interfere with inadequately protected medical devices,
!
including pacemakers. Consult a physician or the manufacturer of the medical device
with any questions.
Changes or modifications to the equipment that Mitsubishi Electronics does not expressly
approve can void the authority to operate equipment within commercial and residential
buildings.
5.2 Signaling and Communications Channels
All Mitsubishi MTs access the MSAT network through six different special “channels”. The
following table defines these channels:
Channel From To Purpose
Pilot Signal CGS MT Reference signal for acquisition
GC-S Channel CGS MT System status, call indication, commands
MET-ST Channel MT CGS Responses to CGS commands
MET-SR Channel MT CGS Call setup and other requests
FES-C Channel CGS MT Communications, in-band signaling
MET-C Channel MT CGS Communications, in-band signaling
5.2.1 Pilot Signal
The MSAT satellite continuously transmits an L-band pilot signal in each of five regional
coverage beams. The MT’s pilot signal strength (initially displayed on the handset) serves as a
reference for locating the satellite before initiating the GC-S acquisition process. The pilot
signal itself does not, however, carry any information.
5.2.2 GC-S Channel
The Group Controller-Signaling (GC-S) channels provide network status information, incoming
call indications, and control messages from the CGS to the MT. The MSAT network can
accommodate up to 16 GC-S channels per beam, per control group (see section 2.2). An MT
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selects one GC-S channel, based upon the last channel used and current network conditions.
Multiple terminals can share this GC-S channel using a Time Division Multiplexing (TDM)
scheme. The GC-S provides information to MTs when they are idle—logged onto the network
but not engaged in a call. Each MT has an encrypted Forward Termi nal Identification Number
(FTIN) as an address for the GC-S channel , protecting all com munications. The received signal
level of the GC-S channel is displayed on the handset after an idle MT completes network
acquisition.
5.2.3 MET-ST Channel
MTs respond to GC-S information and commands through the MET-ST channel. Based on
traffic conditions, the ground segment will assign a specific number of MET-ST channels to each
GC-S channel. The TDMA channel structure is at some fixed time slot following a GS-S
request/command. A unique Reverse Terminal Identification Number (RTIN) identifies METST messages—the RTIN is equivalent to the Electronic Serial Number for each MT.
5.2.4 MET-SR Channel
The MET-SR channel transmits unsolicited MT requests to the ground segment such as call
setup, and beam log-on. Each control group (see Section 2.2) can have up to 64 MET-SR
channels. Access to the MET-SR channels is on an as-needed basis using a “Slotted A LOHA”
protocol. This protocol selects an available MET-SR channel at random, transmits its message in
the next available time slot, and then waits a specific amount of time to receive an
acknowledgment from the ground segment (over the GC-S channel). If an acknowled gment is
not received in the proper time frame the MT will wait a random amount of time and then
attempt to re-transmit the message. The MT also receives information from the ground segment
on the MET-SR channels that help in congestion control. The RTIN also identifies messages
from the MT to the ground segment on these channels.
5.2.5 MET-C Channel
The MET-C channel transmit (1) voice and data communications from the MT to the ground
segment and (2) in-band signaling. The ground segment assigns the channel to a specific MT
(over the GC-S channel) in response to a call setup request (over the MET-SR chann el). The
MET-C channels use Single Channel Per Carrier (SCPC) / Frequency Division Multiplexing
Access (FDMA). This means that each channel occupies its own dedicated 6 kHz of spectrum
during a call. The MET-C channel is voice activated, only transmitting when voice or data bits
are present. During an active call, the channel includes multiplexed in-band signaling messages
for network management and call control functions like on-hook and connect acknowledgment.
5.2.6 FES-C Channel
The FES-C channel sends (1) voice and data calls and (2) in-band signaling to the MT, from the
ground segment. The ground segment assigns the FES-C channel (via GC-S channel) to an MT
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in response to a call setup request (over the MET-SR channel). Like the MET-C channel, FES-C
channels also use SCPC/FDMA access in a dedicated 6 k Hz, voice activat ed slot. Likewise this
channel also includes multiplexed in-band signaling messages for network management and call
control functions like ring command and on-hook command.
5.3 Modulation & Encoding
The digital bit stream containing voice call, data call, and command information are Differential
Quaternary Phase Shift Keying (DQPSK) modulated onto the L-Band RF carrier. Phase Shift
Keying is a popular digital satellite modulation technique which assigns (and transmits) a
specific phase of the carrier frequency to the value of the sample period. For QPSK there are
four phase values that correspond to two bits of sampled data. In differential QPSK, the phas e is
also encoded with a binary algorithm or logic, like XOR or AND functions. This figure below
illustrates differential encoding and modulation functions.
Processed Digital Voice
or Data Bits
Processed Signaling Bits
M
U
X
Odd Bits
Even Bits
n
c
o
d
e
r
e
I (n)
Q (n)
o
d
u
l
a
t
o
r
m
L-Band RF
at Phase x
(x=+45,+135,-45,-135o)
L-Band RF Carrier Signal
The MET-SR and MET-ST channels use binary Differential Phase Shift Keying (DPSK)
modulation, where only two phases (+90o, -90o) correspond to the bit values 1 and 0. The
demodulators for each channel type reconstruct the bit encoded bit stream described above.
5.4 Signal Processing
Prior to modulation on the transmit side and after demodulation on the receive side, the MT
digitally processes the actual voice, data, and signaling to improve performance and enhance
privacy. These following sections briefly review these processing methods. For a complete
discussion of privacy and security capabilities, see Section 5.5.
5.4.1 Scrambling
All digital voice and data bits, as well as signaling messages, are scrambled before being
encoded and modulated for transmission to ensure privacy. The scrambler is a Pseudo-Noise
(PN) scrambler with a 15-stage shift register. During each bit cycle, the output of the 15-bit shift
register adds to the incoming information bit, resulting in the output bit. The output of the shift
register derives from some binary combination (e.g. XOR, AND, etc.) of the resident 15 bits,
with results feeding back into register during each cycle. This process continuously changes the
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scrambling bit. Since the MT randomly selects the initial contents of the shift register (starting
each scrambling process) the output is also random. The MT and ground segment can scramble
and de-scramble the communications link because the MT transmits the initial scrambling
pattern to the ground station.
5.4.2 Interleaving
Interleaving is a process by which the information bits to be communicated are “shuffled” in
some organized manner. Interleaving improves performance on the digital link by mixing up the
bits such that if a short fade or blockage of the signal results in the loss of some bits, they would
end up being widely dispersed in the received information bits after they are deinterleaved,
resulting in little or no impact. The interleaver used in the MT is a block interleaver in which
data is read into the interleaver by rows and then taken out of the interleaver by columns, thus
mixing up the bits in a structured way. The interleaver is only used on data bits and signaling
bits (digital voice bits are not interleaved) and the block size of the interleaver (i.e. number of
rows and columns) is different depending on the operating mode.
5.4.3 Forward Error Correction
Forward Error Correction (FEC) also improves communications performance for the data and
signaling bit—the CODEC performs FEC for voice bits. The MT uses convolutional encoding,
where two or more bits are transmitted for each original bit based upon the contents of a shift
register. Specifically, the MT uses a 1/2 rate en coder of constraint length K=7. Therefore the
MT convolutional encoder produces two output bits based on the summation of the last seven
bits. The technique, called Viterbi decoding, re-assembles the information into its most likely
original form.
5.5 Security Functions
5.5.1 Electronic Features
Mitsubishi MTs, including land mobile and fixed site configurations, offer five key electronic
security features:
♦ Handset Lock Code
♦ Security Code
♦ Call Restriction Levels
♦ Authentication
♦ Communications Scrambling Vector
The basic handset has a user programmable 3-digit lock code. W hen locked the handset can not
place or receive calls, except for 911 (or other emergency numbers in the Number Assignment
Module, or NAM). Regular use of the handset lock will significantly mitigate the risk of
unauthorized users.
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A 4-digit security code allows users to set call restrictions, change the 3-digit handset lock code,
reset an accumulated talk timer, and change the status monitor. Users can input their 4-digit
security code into the MT during NAM programming. Call restriction levels include: no
restriction, recall memory locations 1-99 only, and receive only.
The MT saves both the handset lock and the call restriction mode settings while off. For
maximum security, users should electronically lock the handset or select receive only call
restriction.
5.5.2 Authentication
Every MT authenticates its identity upon call setup and during commissioning and performance
verification tests. The authentication process encrypts a random variable and an Access Security
Key (ASK) to form an authentication code. The MT and CGS independently generate the
authentication code, with the MT sending its version of the code to the CGS at the beginning of
each call event. The CGS in turn verifies that the MT can continue call setup, commissioning, or
performance verification tests. The authentication code is both random and e ncrypted for each
event, with only the specific MT and CGS having all information required to produce the code.
5.5.3 Scrambling
All communications between a specific MT and the CGS are scrambled before transmission.
Because the scrambling function derives from a random number that each MT selects, only that
specific MT and the CGS can de-scramble intelligible communications.
5.6 Network Data Distribution & Storage
During initialization, and each time the MT is powered on, the CGS transmits network data to
that MT. This data includes network status, channel parameters, and signaling channel
assignments. The MT stores some of this data in Non-Volatile Random Access Memory
(NVRAM), retaining the information when powered down. For example, an MT saves the
system table in NVRAM, defining the last beam and signaling channel used. The system table
helps the MT in the network acquisition process. The CGS continuously transmits detailed
system status and assignment information to operating MTs through the GC-S channel (idle MT)
or FES-C in-band signaling (active MT).
5.7 Shutdown Conditions
There are four conditions that may cause a MT to cease transmission or automatically shut down.
All dealers should be aware of and understand these conditions for trouble resolution and user
training.
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♦ System Deactivation
♦ Low Power
♦ Temperature Alarms
♦ Loose or Disconnected Cables
System deactivation is when the CGS commands the MT to deactivate (handset display: Shut
Down) due to network congestion, MT failure of a performance verification test, detection of
corrupt NVRAM, or the need for excessive re-transmissions to successfully deliver messages. It
is also possible that the Aeronautical Mobile Satellite Service (AMSS) may exercise its priority
access rights in emergency situations. In these cases the dealer must coordinate with the MSAT
service provider to request reactivation. This situation may also require re-commissioning.
An MT may automatically shut itself down if it detects low power or high temperatures. In both
cases the MT notifies the user of the situation with an audible warning tone prior to automatic
shutdown. In most cases the user can terminate a call in progress before automatic shutdown.
Finally, an MT may power down or not be able to power on if there are loose or disconnected
cables. Proper MT operation requires secure connections between the handset, CTU, and AU.
Damage to cables may also cause the power-off condition.
5.8 Operation
5.8.1 Initialization
The Mitsubishi MTs run through a hardware and software self-test procedure every time a user
applies power. The MT will request programming information the first time that it powers up.
After programming, described in Section 7, the unit will automatically power down. When the
user powers up again, the MT will request the Pilot Frequency Code (PFC) and the
Commissioning Frequency Code (CFC), which the dealer obtains from the MSAT service
provider. These codes identify the pilot channel frequency (for satellite location) GC-S channel
frequency (for commissioning messages). The land mobile MTs can now find the satellite and
begin commissioning. Fixed site and transportable MTs require manual antenna pointing
towards the satellite. This setup procedure is described in the following section (5.8.2).
The commissioning procedure automatically starts after the user responds to the push SEND
button prompt from the MT. The initialization request from the MT goes over a special METSR channel to the CGS. The CGS then verifies that the MT is registered and sends a response,
including initial assignment and identification information. The CGS then commands the MT to
perform a Performance Verification Test (PVT) including both the signaling and the
communications channels. For communications channel testing, the MT enters a loopback
mode, sending data to the NCC for checking errors. After the MT successfully completes the
PVT, the NCC sends a commissioned indication to the MT, indicating that it is ready for service.
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5.8.2 OmniQuest® Setup
Upon power up, the ST251 MT runs through a self-test procedure to check the inte rnal status of
hardware and software. If no internal faults are detected, the unit will prompt the user to point
the TPB antenna towards the satellite and then to press * to initiate automatic GC-S selection.
During automatic GC-S selection, the MT selects a GC-S channel based upon information stored
in NVRAM about the status of the MSAT system when the MT was last logged on. The MT
searches GC-S channels in an organiz ed manner starti ng wi th t he GC-S chann el wi thin the beam
which was last used and then moving on to others if this channel or beam is not available (based
on signal strength and error rates). If the MT has been moved to another beam area since it was
last operated, it must also perform a log-on procedure to notify the CGS about which CGS
channel it is using (within a specific beam). Once a log-on response is received from the CGS,
the MT is available for calls and the NO SVC indicator on the handset should turn off.
5.8.3 Placing a Telephone Call
To place a voice call, the user dials the telephone number on the keypad, or recalls a number
from a memory location, and then presses the send button. Pressing speed dial keys, P1-P3,
performs both telephone number input and send functions. The MT send button/function
transmits a call request to the CGS (MET-SR channel) indicating the type of call (voice or data),
the telephone number, and the RTIN. In response, the CGS sends the MT’s transmit and receive
frequency assignment for the call (GC-S channel). The MT then forwards the scrambling vector
for the call and the MT access security check. End-to-end communications begin after the MT
receives ringing and off-hook sign als through in-band signalin g on the FES-C channel. The MT
user presses the end button to transmit an on-hook command, which the ground segment
acknowledges over the FES channel.
5.8.4 Receiving a Telephone Call
While the MT is logged onto the network, but not engaged in a call, it continuously monitors the
GC-S signaling channel for network status information updates, incoming call indications, and
other control messages from the CGS. The MT displays incoming call type (voice or data) from
the encrypted FTIN and sends an acknowledgment to the CGS over the MET-ST channel. The
ground segment in turn assigns transmit and receive frequencies. The remainder of the call
structure is the same as described in section 5.8.3.
5.8.5 Data Communication
Data calls are very similar to voice calls, with identical CGS signaling. Data calls identify their
communications rate and format on the MT-SR channel along with the called phone number.
The scrambling vector also includes the character format and speed of the data call. All
Mitsubishi MTs can receive and send calls either manually with the handset or automatically
with Data Terminating Equipment (DTE), such as a personal computer. Data communications
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use standard AT commands, which common PC software applications normally embed within
their modem script. The MT Owner’s Manual and Appendix D provide information beyond the
description in this section.
When an MT receives a data call, it produces a shorter ring with longer pauses and displays
SatData Call on the handset. When the MT answers a data call, it routes the incoming FES-C
channel to the DATA port on the transceiver. The MT user can send a data call directly from the
handset (like a normal voice call) or automatically through the DATA port of the transceiver by
using AT commands from a PC. Users can answer calls one of three w ays: 1) pressing a k ey on
the basic handset, 2) automatically after three rings with auto-answer function enabled, or 3)
automatically after a specific number of rings (greater than 1) specified in the application
software.
Users should execute three key steps prior to data call operations:
1. Obtain a data telephone number from the dealer or service provider.
2. Program and commission the MT, if this has not already been done.
Hint: Program the DATA telephone number into an unused memory location for future reference
(e.g. memory location 99).
3. Connect the data interface (D/I) cable (provided b y customer) to the DTE port (TU) and the
COM port (DTE).
The following table lists key data port (TU) characteristics for reference:
Mechanical Interface DB-25 female
Electrical Interface RS-232
Communication mode Full duplex
Synchronization Start - Stop systems (Asynchronous)
Communication rate 1200bps, 2400bps, 4800 bps
Flow Control None
Error Correction Rate 1/2 convolutional coding
Functionality All “AT” commands listed in the Operating
Instructions
Every MT interfaces with one of the following character formats:
Start Bits Data Bits Parity Bits Stop Bits
1 7 even or odd 1
1 8 none 1
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Mitsubishi Electronics recommends the following DTE setup:
Communication rate 4800bps
Character format 8 bits, No parity, 1 stop bit
Flow Control None
1. Use a serial port (COMx), on the PC to MT connection for data transmission.
Note: The COM1 port is normally utilized for this connection.
2. The MT transmits all data transparently (RTS signal line is not used / CTS line always high)
so HW flow control is not necessary (i.e. ignored) but software flow control between end
equipment can be used (e.g. XON/XOFF).
3. When choosing a modem driver, select a basic Hayes compatible 4800bps modem as default,
or something as close to this as possible.
4. Various transfer protocols are supported; the standard configuration should be Zmodem.
5.8.6 Net Radio/Dispatch Operation
Net Radio or Satellite Dispatch capability is a special MT function that provides a half-duplex
digital network (or talk group) capability. This service requires the use of the Push-to-Talk
(PTT) Microphone (SZ300A), external speaker accessory, and a separate service subscription.
A customer can configure and re-configure up to 256 talk groups, or dispatch channels, with as
many as 10,000 MTs in all talk groups. Each MT can belong to 15 different talk groups. Talk
group configurations and attributes download from the ground segment every time an MT
powers on. The Net Radio service uses special protocols and messages on each of the previously
defined channels for downloading system parameters, setting up and tearing down networks, and
establishing communications between the speaker and all other members in a talk group.
Dealers should be able to provide end-users with more detailed information on Net Radio service
offerings.
5.9 Possible Cable Extensions
The following figure and table describe acceptable cable extensions for Mitsubishi MT
configurations. MT modifications should not include full lengths for Extension A and Extension
B. Note that adding any extension cable exposes the MT to various electromagnetic interference
conditions, therefore Mitsubishi Electronics does not guarantee audio performance.
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Extension Cable
Ref: Figure 1.
A
B
M\F means the cable has one male connector and one female connector, If the cables are not available, a standard
“gender bender” may be utilized.
Short Length \
Minimum Cable Type
50 ft \ ~15m
RS-232C Standard - M\F*
26AWG - <50pF\ft
Drain wire connects
connector housings for a
ground.
50ft \ ~15m
Flat Satin
RJ-45 M\F - 26AWG
Long Length \
Minimum Cable Type
100 ft \ ~30m
RS-232C Extended - M\F*
24AWG - <15pF\ft
Drain wire connects
connector housings for a
ground.
100ft \ ~30m
Category 3 LAN
RJ-45 M\F - 24AWG
5.10 Multiple Handsets
Mitsubishi MTs configured with both the basic handset and PTT handset can automatically
switch operations between regular voice and dispatch. One of the devices will always be in a
“sleep” mode, where the display does not remain in contact with the CTU. However, the
transceiver will automatically “wake up” the handset and route an incoming call when the MT is
idle. Users can manually wake up a sleeping handset with the press of any button (besides
power), for more than half a second. The SZ300A PTT Microphone Operating Instructions
manual provides a complete description of this “multi-terminal operation”.
5.11 Other Operational Considerations
♦ Fixed Site, ST221M, pointing requirements do not account for magnetic offset effects. This
phenomenon causes a difference between ma gnetic north and true north, which varies more
at high latitudes and over time.
♦ All configurations require a clear line of site to the satellite for reliable communications. The
L-Band MT signals must effectively propagate 22,300 miles / 36,000 km to the satellite
without significant distortion or attenuation. Mitsubishi MTs can communicate through most
glass (though some tinted or reflective glass coatings will attenuate the signal), plastics, and
ST200 Series Technical Support Manual 27 January 2000
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