Ericsson Lbi 38756 Users Manual 38652 MDS 148 174 MHz MOBILE RADIO COMBINATION

LBI-38756 to the manual 10942520-c999-44c3-9859-9637e3f3bdf8

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Mobile Communications

MDS

148-174 MHz MOBILE RADIO

COMBINATION

TABLE OF CONTENTS

MAIN BOARD ASSEMBLY . . . . . . . . . . . . . . . . . . . LBI-38756

FRONT PANEL ASSEMBLY . . . . . . . . . . . . . . . . . . . LBI-38757

POWER AMPLIFIER ASSEMBLY . . . . . . . . . . . . . . . LBI-38758

SERVICE SECTION . . . . . . . . . . . . . . . . . . . . . . . LBI-38759

Maintenance Manual

LBI-38652

Printed in U.S.A.

Copyright © April 1992, Ericsson GE Mobile Communications, Inc.

TABLE OF CONTENTS

Page

SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

PACKAGE NUMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

RADIO DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

MAIN BOARD ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

FRONT PANEL ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

POWER AMPLIFIER ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

PC PROGRAMMABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

EXTERNAL SPEAKER (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

BATTERY POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

EASY ACCESSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

SERVICE AIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

DETAILED TYPE 99 OPERATION AND PROGRAMMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

GE TYPE 99 FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MOTOROLA FORMAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

MECHANICAL PARTS BREAKDOWN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

MECHANICAL PARTS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

FIGURES

Figure 1 - MDS Conventional Radio Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

TABLES

Table 1 - Channel Guard Tone Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 2 - Primary and Equivalent Digital Codes (OCTAL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Table 3 - Tone Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 4 - Tone Generator Frequencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 5 - Motorola Type Coder Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 6 - Motorola Group Call Tone Groups (TG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Table 7 - Motorola Group Call Tone Groups (TG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

SPECIFICATIONS

GENERAL

Frequency Range Transmit: 148-174 MHz

Receive: Same as Transmit

Channel Spacing 25 kHz

Frequency Stability ±5.0 ppm

Operating Temperature Range -30 to +60°C

Battery Voltage 13.6 volts ± 10% (meets specs)

± 20% (operational)

Radio Current Drain OFF: 0.01 amps

Rx Squelched: 0.9 amps

RxOn: 1.5 amps

Tx On: 10.0 amps

Size 170mm W x 216mm L x 53mm H

TRANSMITTER

Tx Two Frequency Spread 26 MHz

RF Power Output 40 watts (+ 146 dBm, Adjustable 20 to 40 watts)

Maximum Deviation ±5% kHz peak

Tx Duty Cycle 20% Intermittent (EIA)

FM Hum and Noise (EIA) -45 dBc maximum

Audio Distortion 5% @ 300 Hz, 3% @ 1kHz, 5% @ 3kHz

RF Load Impedance 50 ohms

Audio Sensitivity 80 mV ±3 dB

Audio Frequency Response Within + 1 ,-3 dB of a 6db/octave pre-emphasis,

300-3000 Hz (EIA)

Spurious Emissions

Conducted

Radiated -16.5 dBm max (Meets DOC & FCC)

-13 dBm max (FCC)

RECEIVER

Receiver coverage

Factory Tuned 148-174 MHz

150-168 MHz

Rx Two Freq Spread 18 MHz (No degradation)

Channel Spacing 25/30 kHz

Sensitivity (12 dB SINAD) -117 dBm (.30 µV)

LBI-38652 LBI-38652

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INTRODUCTION

The Ericsson GE Conventional MDS VHF Radio is a rug-

ged two-way FM mobile radio which operates in the 148-174

MHz frequency band. The MDS is a wide band synthesized ra-

dio utilizing microcomputer technology to provide reliable

high quality simplex two-way mobile communications. Its

transmitter output power level is 40 watts over the wide band-

width of each split. The receiver has an allowable 12 MHz

maximum receive channel separation. There are two versions

available, a 2-channel and an 8-channel. The basic radio pack-

age includes the following features:

•Microprocessor Control

•Synthesized RF Channel selection (frequency control)

•7-Segment LED Channel Display

•Multi-tone Channel Guard (CTCSS) Encode/Decode

•Multi-code Digital Channel Guard (DCG)

Encode/Decode

•Automatic Hook Switch Channel Guard Disable

•Channel Activity Sensing (CAS)

•Carrier Control Timer (CCT)

•5 ppm frequency stability

•Type 99 Tone Decode

•Field Programmable with PC

•Fixed Squelch, threshold programmable

•Internal 4-watt Speaker, with volume control

•Front Mounted Microphone Connector

•Rear Mounted Antenna TNC Connector

•Rear entry power connections

•ANI Encode

The small size of the MDS radio makes it ideal for front

mounting in conventional vehicles. The radio is operated with

a simple hand held microphone in combination with the fol-

lowing operating controls, all located on the front panel:

•Power ON/OFF Switch

•Channel UP/DOWN Selector

•Volume UP/DOWN Control

•Monitor Switch for Channel Guard Disable

•Type 99 Tone RESET Switch, to reset the tone decoder.

Refer to the Operator’s Manual LBI-38651 for a complete

description of the operating procedures.

RADIO DESCRIPTION

MAIN BOARD ASSEMBLY

A sturdy aluminum casting houses the Main Board Assem-

bly N29/85154001920. There is complete accessibility to the

Main Board with the radio’s top and bottom covers removed.

The Main Board contains the following circuits:

•Microprocessor and associated Logic

•Frequency Synthesizer

•Transmitter Exciter

•Receiver

•Audio Processing (for both transmit and receive paths)

•Tone and Squelch Processing (for both transmit and

receive paths)

•Voltage Regulators

Logic Circuitry

The radio’s logic circuitry includes the 80C535 microproc-

essor with associated EPROM and Electrically Erasable

PROM (EEPROM) memory and latch circuitry. The Micro-

processor controls the functions of the transmitter, the receiver,

the inputs from the operator and the outputs to the operator.

Synthesizer

A programmable Synthesizer generates both transmit and

receive operating frequencies. It includes a synthesizer chip, a

dual modulas counter, a temperature compensated reference

oscillator (TCXO) and a voltage controlled oscillator (VCO);

all part of an operating phase lock loop, with its requisite loop

filter.

Transmitter

The radio transmitter includes the Synthesizer’s modulated

VCO and the fixed tuned exciter amplifiers. The exciter ampli-

fiers are wideband, covering the VHF band without retuning.

The exciter output is fed to the Power Amplifier Board through

a coax cable. The exciter provides 35 dB of gain to drive the

Power Amplifier with 2 watts. The transmitter output level at

the antenna connector is factory set for a rated output power of

40 watts. The power control circuit detects the power output of

the Power Amplifier. Using the error signal, the power control

circuit varies the DC supply voltage to the first stage of the ex-

citer. This will hold the transmitter output level constant.

SPECIFICATIONS (Cont.)

Spurious Emissions

Radiated Meets FCC requirements

Conducted -57 dBm maximum

Rx Spurious Response 70 dB minimum

Adj Ch(2-Sig) Selectivity -75 dB max @ 30 kHz (EIA)

Intermodulation Attenuation -75 dB minimum

Rx Modulation Acceptance ± 7 kHz minimum

Audio Distortion 2% maximum @ 0.5 Watt (EIA)

10% maximum @ 4 Watts and 1 kHz

Audio Frequency Response Within + 2,-8 of a 6dB/octave de-emphases,

300-3000 Hz (EIA)

Rx Hum and Noise

Unsquelched -50 dB maximum

Squelched -70 dB maximum

Audio Output Power 4 watts, @ <10% Distortion

Speaker Impedance 4 ohms

MDS RADIO PACKAGE NUMBERS

PACKAGE NUMBER DESCRIPTION

TLH22 VHF 2 CHANNEL, 40 WATT

TLH28 VHF 8 CHANNEL, 40 WATT

OPTIONS

OPTION NUMBER DESCRIPTION

MC3G DESK TOP MIC

ANIR 1/4 WAVE, ROOF MT ANTENNA W/TNC CONNECTOR

ZM3L EXTERNAL WEATHERPROOF SPEAKER AND CABLE

LS1F MIL SPEC SPEAKER, 4 OHMS, 5 x 5

CD1E SPEAKER CABLE

PD1A NOISE FILTER KIT

SU1C ALARM RELAY KIT

EC1A DOC POWER SET

MA1L DESK TOP RADIO MOUNTING WEDGE

PS1D 240 VAC-12 VDC, 13A 50/60 Hz Power Supply

PS5K 120 VAC-12 VDC, 13A 50/60 Hz Power Supply

LBI-38652 LBI-38652

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Figure 1 - MDS Conventional Radio Block Diagram

LBI-38652 LBI-38652

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Receiver

The RF front end of the receiver includes the PIN diode

T/R switch, the tuned bandpass preselector filters, and the

low noise RF amplifier. The filters have a 12 MHz band-

width, and are factory tuned for receiving in the 150-162

MHz bandwidth. Refer to the Service Section LBI-38759 for

retuning to a different frequency. The first mixer (with its

low side injection from the VCO) generates a 45.000 MHz

IF signal which is filtered with monolithic crystal filters hav-

ing a 15 kHz bandwidth. A 455 kHz low IF circuit module

contains the second local oscillator, the second mixer with

low side injection, external ceramic filters, an external

44.545 MHz crystal for the oscillator and the FM quadrature

detector circuit.

Transmit Audio Processing

In the transmit audio path, the audio from the micro-

phone is passed through a 3 kHz low pass filter, preempha-

sized and hard limited for a maximum modulation peak

deviation of 4.5 kHz. A MIC Mute switch is controlled by

the logic as appropriate for tone or voice modulation of the

transmitter. Channel Guard tones and the A.N.I. signal from

the microprocessor are summed into the audio path before

the gain control. Next, a 3 kHz post limiter low pass filter at-

tenuates frequencies above 20 kHz by more than 54 dB be-

fore passing the audio signal on to the modulation input of

the VCO.

Receive Audio Processing

Audio from the demodulator enters the voice path

through a 300 Hz high pass filter, followed by a 3 kHz low

pass filter. A "Receive Mute" switch is provided so the voice

signal can be muted by the microprocessor when it sums its

Alert tones into the path. The "Receive Mute" switch attenu-

ates the voice audio by 50 dB when the Alert tones are

summed into the path. The path is completed with a gain

control, and a logic controlled switch for speaker muting

while transmitting. The audio power amplifier which deliv-

ers 4 watts to the speaker is connected on the Main Board,

but is mounted on the aluminum chassis for heat sinking.

Tone And Squelch Processing

The Channel Guard path includes a 220 Hz low pass fil-

ter for passing the received Channel Guard tones without

audio. A tone limiter insures a 5 volt pp maximum input tone

level to the microprocessor.

In the Squelch path, noise above the audio voice frequen-

cies is filtered through a 6 kHz high pass filter; amplified

and then limited. A DC detector generates a DC voltage rep-

resenting the amplitude of the noise. This DC voltage is ap-

plied to a comparator. The out-put from the comparator is

fed to the microprocessor The microprocessor squelches the

receiver under conditions of high noise and absence of car-

rier.

Since the frequencies of Type 99 tones fall in the voice

band, they are passed through the 300 Hz high pass filter in

the voice path. Next, the tones are shunted through a closing

switch and passed into the tone path in front of the tone

limiter. The tone limiter passes the tones on to the tone de-

tector port of the microprocessor.

Voltage Regulator Circuitry

The battery voltage (IGN A +) enters the radio at J11 on

the Power Amplifier Board. From the PA Board IGN A + is

routed directly to the Main Board where it is filtered and

passed through a relay as A + _SW. A + _SW is fed to the

regulator circuits which provide a regulated 8, 5 and 2 volts

to the appropriate circuits throughout the radio. A + _SW is

also fed to the Audio Power Amplifier circuits.

FRONT PANEL ASSEMBLY

The Front Panel Assembly (N29/85154000950) houses

the Front Panel Board, the internal 4-watt speaker, and all

control switches and indicators for the radio. The panel is

made of highly durable plastic with rounded corners and re-

cessed controls and indicators for passenger safety. The

Front Panel Board mounts on back of the Front Panel. The

following display elements are on the front panel:

•Channel Number Display, 7-segment LED with

numbers 1-8

•Transmit Light, lights when radio is transmitting

•Busy Light, ON when channel is busy

See the Operator’s Manual LBI-38659, for a detailed

description of the indicators, controls and operation of the

radio.

The microphone connector is an RJ-11 type, female con-

nector mounted to the Main Board but located on the front

panel of the radio. A strain relief is provided to secure and

protect the microphone connector. A microphone Hook

Switch with magnetic sensing is provided with the radio to

be mounted externally on the dashboard of the vehicle. Re-

moving the microphone from the Hook Switch disables the

Channel Guard, enabling the operator to monitor the channel

before sending a message.

POWER AMPLIFIER ASSEMBLY

The Power Amplifier Assembly (N29/85154000930) con-

tains the Power Amplifier Board mounted to an aluminum die-

cast heatsink. The PA Board contains the RF Power Amplifier,

the RF output LP harmonic filter, the PIN diode T/R switch,

and a stripline directional coupler for power output sensing.

The RF Power Amplifier is driven by the output of the ex-

citer on the Main Board, which is connected by coax to the PA

Board. The PA Board amplifies the output from the Main

Board to a level of 40 watts over the frequency range of 148-

174 MHz. The output of the PIN diode T/R switch is coaxially

connected to the receiver front end circuitry on the Main

Board. The T/R switch has a separate connection to the an-

tenna jack. The IGN_A + External Speaker and External

Alarm lines connect to the Power Amplifier Board at J11.

FEATURES

PC PROGRAMMABLE

The entire personality of the radio is programmed into the

radio using an IBM or IBM compatible personal computer and

the following equipment:

•Serial Programming Interface Module TQ-3310

•MDS Programming Cable TQ-3361

•MDS Conventional Programming Software TQ-3363

The interface module is connected between a serial port on

the computer and the RJ- 11 microphone connector on the

Front Panel of the radio. An RS-232 cable connects the serial

port to the Interface Module. The Programming Cable (TQ-

3361) is connected from the Interface module to the RJ- 11 mi-

crophone connector on the front of the radio. Refer to TQ-3363

for a complete set of instructions on how to program the MDS

Conventional radio.

Tracking Data

The test handset is used to make operational circuit adjust-

ments in the radio using digitally controlled potentiometers.

The resulting "Tracking Data" is stored in the EEPROM per-

sonality of the radio. A utility in the PC Programming software

can be used to read the Tracking Data. All programming is

done through the microphone connector on the Front Panel of

the radio, without the need of opening the radio package. The

Tracking Data adjustments made with the test handset include

the following:

•Reference voltage for Transmit RF power output level

•Voltage for VCTCXO frequency adjustment

•Modulation deviation adjustment for VCO

•Channel Guard modulation deviation adjustment

•Microphone gain adjustment, 2 pots in voice path

•Other filter adjusting pots

Programmable Features/Options

Squelch Tail Elimination

Squelch Tail Elimination (STE) is used with both tone and

digital Channel Guard to shorten the noise burst between re-

ceiving a call and muting the receiver audio path. This is com-

monly referred to as reducing squelch tails. The STE burst is

transmitted when the microphone PTT is released. The receiv-

ing radio de codes the burst and mutes the receiver audio for

250 ms. The duration of this mute time includes time for the

end of transmission plus that of the squelch tail. The radio

looks for STE on the received signal when the microphone is

either ON or OFF-hook. The STE is enabled for transmit

and/or receive by PC programming the radio’s personality.

Carrier Control Timer

The Carrier Control Timer (CCT) turns off the transmitter

after the microphone push-to-talk (PTT) switch has been keyed

for a pre-programmed time period. A pulsing alert tone will

warn the operator to unkey and then rekey the PTT to continue

the transmission. The timer can be programmed to time out for

15 to 225 seconds in 15 second increments. The CCT will be

the same for all channels in the personality.

Type 99 Decode

Type 99 2-tone sequential selective calling is programma-

ble on a per channel basis, with the radio enabled to decode

only. On a channel where Type 99 has not been selected in pro-

gramming, the Type 99 tone decoder is disabled. The Type 99

selective calling option operates in either Type 99 Select Mode

or Type 99 Monitor Mode. The default mode can be designated

in programming. See the section DETAILED TYPE 99 OP-

ERATION AND PROGRAMMING, on page 11, for more

detailed information on Type 99 Decode.

Automatic Number Identification (A.N.I.)

As an option, one ID number per radio is programmed on a

per channel basis. The microprocessor generates the special

1600 Hz A.N.I signal which is coded with a 4-bit phase revers-

ing code. It is sent at a 400 baud rate as part of the handshak-

ing preamble to a repeater just after PTT has been pressed, or

alternatively just after release of the PTT key. A.N.I. is re-

LBI-38652 LBI-38652

4

ceived and optionally de modulated by the repeater as part of

the system protocol when so installed.

Receive-Only Operation

Channels can be programmed to receive-only operation.

Channels cannot be programmed for Transmit-only operation.

Busy Channel Lock Out

With Busy Channel Lock Out programmed, the radio can-

not transmit on a channel already busy. If the channel is busy,

fast pulsing beeps will sound (without stopping), until the PTT

switch is released. The radio must be programmed for, and re-

ceiving, the correct Channel Guard. The combination of Chan-

nel Guard and Busy Channel Lock Out prevents the user from

talking on a channel that is already in use (busy).

When the Busy Channel Lock Out option is enabled with-

out programmed Channel Guard, the user is prevented from

transmitting over a channel until there is no carrier present in

the channel.

Minimum Volume Level

The Front Panel VOLUME controls permit adjustment of

the audio level. Minimum levels are programmable. This fea-

ture prevents missed calls due to a low volume level.

Power Level

Incremental transmitter power level change can be pro-

grammed to permit setting the output power to rated value. The

selected power level will be used for all channels.

Channel Guard

Channel Guard provides a means of restricting calls to spe-

cific radios through the use of a continuous tone coded squelch

system (CTCSS), or a multi-code digital squelch system

(DCG). Tone frequencies range from 67 Hz to 210.7 Hz. There

are 83 standard programmable digital codes.

The Channel Guard tone frequencies and codes are soft-

ware programmable. Both tone frequencies and digital codes

may be mixed on each channel. The frequencies and codes are

shown in Tables 1 and 2. A Channel Number display that does

not flash, indicates that Channel Guard is enabled, or that

Channel Guard is not programmed. A flashing Channel Num-

ber indicates that Channel Guard is programmed and disabled.

EXTERNAL SPEAKER (Optional)

The power connector provides a place to connect an exter-

nal speaker. The internal speaker must be disconnected when

an external speaker is used.

BATTERY POWER

The vehicle 12 volt battery with negative ground is all that

is required for operation of the radio. A cable connects the bat-

tery to a male connector mounted on the back of the radio. The

radio can also be powered with the vehicle ignition switch.

EASY ACCESSIBILITY

The radio circuitry is mostly contained on a single Main

Board, with the exception of the PA Board and the Front Panel

Board. Access to the Main Board and the inside of the radio is

easy with the removal of the top and bottom covers with two

screws each. Then the few adjustment controls (most are ad-

justed with PC programming) can be easily reached. Four more

screws will permit removal of the front panel, giving access to

the Front Panel Board along with the switch and indicator cir-

cuitry.

SERVICE AIDS

•Test Handset Kit (SPK9024), includes Handset

(19A706965P3) and Coiled Cord (19D901619P2)

•Test Adapter Box (TQ0618)

•Programming Cable (TQ3361)

•PC Programming Adapter (TQ3310)

•Power Contact Extraction Tool (458994-2)

DETAILED TYPE 99 OPERATION

AND PROGRAMMING

The original Type 99 programming provides individual,

group and super group call decode. The motorola format two-

tone sequential signaling schemes can also be decoded.

The MDS Conventional radio can be PC programmed with

up to two separate tables of tones. Either the GE Type 99 for-

mat or the Motorola format can be assigned to each tone table.

The tone decoder (Individual, Group and Quick Call for the

Motorola format) can be enabled individually for each channel.

Once enabled, one of the two tone tables can be selected for

each channel.

The Group Call format allows communication with all

radios within a subgroup. The Super Group Call in GE tone

systems) or Quick-Call (in Motorola tone systems) allows

communications between all radios in a system.

The MDS Conventional radio can operate in either the

Type 99 Select Mode or the Type 99 Monitor Mode. In the

Type 99 Select Mode the speaker audio remains muted until

the user’s own Type 99 code is decoded, unmuting the audio

and permitting receipt of the message. At this time an audi-

ble alert sounds and an "A" appears in the display. The "A"

will remain displayed (instead of the selected channel num-

ber) until the RESET button in pressed or the transmitter is

keyed.

Table 2 - Primary and Equivalent Digital Codes (OCTAL)

Table 1 - Channel Guard Tone Frequencies

LBI-38652 LBI-38652

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In the Type 99 Monitor Mode the receive audio remains

unmuted permitting the user to monitor all activity on the

channel. When the user’s own Type 99 tones are decoded, a

beep sounds and an "A" will be displayed, calling his atten-

tion to his own call now on the channel.

Toggling the RESET button allows the user to choose

either the Type 99 Select Mode or Type 99 Monitor Mode of

receiving.

GE TYPE 99 FORMAT

Tone frequencies in the GE tone system fall within the

range of 517.5 to 997.5 Hz.

In the GE tone format, the first tone may be from tone

group A (for Individual or Group calls) or from tone group C

(for Super Group calls). The second tone may be from tone

group B (for Individual calls) or from tone group D (for

Group and Super Group calls).

The GE tone format is illustrated below:

INDIVIDUAL CALL FORMAT

<---1.0 SEC--->

±20%

TONE A

<---200 MS--->

±25%

GAP

<---1.0 SEC--->

300%, -0%

TONE B

GROUP CALL FORMAT

<---1.0 SEC--->

±20%

TONE A

<---200 MS--->

±25%

GAP

<---1.0 SEC--->

+300%, -0%

TONE D

SUPER GROUP CALL FORMAT

<---1.0 SEC--->

±20%

TONE C

<---200 MS--->

±25%

GAP

<---1.0 SEC--->

300%, -0%

TONE D

For example, assume the paging number to be 123. The

first digit of the paging number is a 1. Look in Table 3 and

read down the column labeled "100’s Digit" to a 1. Read

horizontally across the column labeled "10’s Digit". The

tone group is B. The second digit of the paging number is a

2. The tone number is B2. Look in Table 4 and down the col-

umn labeled ’Tone Designator" to find B2. Read horizon-

tally across the column labeled "Tone Frequency". The first

tone frequency is 787.5 Hz.

To determine the second tone frequency look in Table 3

and as before, find the first digit of the paging number (1).

The second tone group is A. The third digit of the paging num-

ber is a 3 and the tone Designator is A3. In Table 4 read down

the column labeled "Tone Designator" and find A3. Read

horizontally across the column labeled "Tone Frequency". The

second tone frequency is 802.5 Hz. For different paging num-

bers, locate the first digit in the "100’s Digit" column and de-

termine the tone frequencies as described in the example.

Tone D is the diagonal tone used (in GE tone systems only)

when the first and second tone frequencies are the same. The

standard frequency for Tone D is 742.5 Hz, but may be pro-

grammed with any tone frequency.

MOTOROLA FORMAT

Tone frequencies in the Motorola tone system are within

the range of 288.5 to 1433.4 Hz. In the Motorola tone format,

the first tone may be one of three tones: A for Individual Call,

B for Quick Call and C for Group Call. The second or final

tone is B in all cases.

The Motorola tone format is illustrated as follows:

INDIVIDUAL CALL FORMAT

<---1.0 SEC--->

(Minimum)

TONE A

<--NONE--->

GAP

<---3.0 SEC--->

(Minimum)

TONE B

GROUP CALL FORMAT

<---1.0 SEC--->

(Minimum)

TONE A

<---NONE--->

GAP

<---3.0 SEC--->

(Minimum)

TONED

SUPER GROUP CALL FORMAT

<------------------------------8 SEC------------------------------>

TONE B

Individual Call

Tables 5 and 6 may also be used to determine the tone fre-

quencies. The first digit of the code determines the tone group

used in the code (see Table 5). Then Table 6 is used to deter-

mine the actual tone frequencies. For a code of 124, the tone

groups used are shown in Table 5. Tone A and Tone B are both

located in tone group 1 and Tone B is tone number 4. Refer to

the following examples for additional information.

Example 1 - Code 098:

The digit "0" in Table 5 (First Digit of Code) shows that

Tone A is in Tone Group 4 and Tone B is in Tone Group 2 (see

Table 6).

Tone number 9 in Tone Group 4 is 524.6 Hz.

Tone number 8 in Tone Group 2 is 879.0 Hz.

Example 2 - Code 265:

The digit "2" in Table 5 shows that both Tone A and Tone

B are both in Tone Group 2.

Tone number 6 is 788.5 Hz.

Tone number 5 is 746.8 Hz.

Group Call (Quick-Call Format)

In Group Call applications, the Tone Group is determined

by Table 7, while the frequency is determined by Table 6. Re-

fer to the following examples.

Table 3 - Tone Groups

The MDS radio is able to recognize the A, B, and C

tones. Individual, Group and Quick Call formats may

be used simultaneously.

NOTE

Table 4 - Tone Generator Frequencies

Table 5 - Motorola Type Coder Numbers

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Example 1 - Group Call Code 07 (also code 27 and 37):

The digit "0" in Table 5 shows that Tone B is in Tone

Group 2 along with 20 to 29 and 30 to 39. Tone number 7 in

Tone Group 2 is 832.5 Hz (see Table 6).

Example 2 - Group Call 98 (also code 48 and 88):

The digit "9" in Table 5 shows that Tone B is in Tone

Group 4 along with 40 to 49 and 80 to 89. Tone number 8 in

Tone Group 4 is 496.8 Hz.

Group Call code numbers range from 00 to 99. How-

ever, there are several Group Calls with the same Tone

B frequency. This limits the total number of Group

Calls to 40.

NOTE

Table 6 - Motorola Group Call Tone Groups (TG)

Table 7 - Motorola Group Call Tone Groups (TG)

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MECHANICAL PARTS BREAKDOWN

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PARTS LIST

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