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LBI-38960
(EEPROM) to store customer frequencies, tones, and options.
The microprocessor provides control data to the digital signal
processor (DSP), conventional tone generation and detection,
frequency data to the synthesizer, and sends and receives data
to another microprocessor in the Front Cap Assembly for the
display and control commands.
SYSTEM BOARD
The system Board controls the main input power to the ra-
dio. The front panel POWER switch and the IGNITION
SENSE input lead provide the necessary signals to the MOS-
FET switching circuit.
The board also interfaces all option connections from the
internal boards in the radio with the optional items outside of
the radio. All options that apply to the radio, interconnect to
the System Board through the back of the radio using and op-
tional cable.
AUDIO AMPLIFIER BOARD
The Audio Amplifier Board provides compression on the
received audio. An audio amplifier is used to drive four watt
audio power into the internal eight ohm speaker or ten watts
audio power into an external four ohm speaker. With a Remote
Mount Kit, the external speaker power is 7.5 watts.
FRONT CAP ASSEMBLY
The Front Cap Assembly contains the Display Board and
houses the internal speaker. The Display Board contains a mi-
croprocessor that senses key closures, updates the eight charac-
ter LED display and ICON displays, and communicates with
the main radio microprocessor on the Logic Board.
ACCESSORIES AND OPTIONS
MICROPHONES
The standard mobile combinations use a transistorized dy-
namic microphone with an internal hookswitch. The micro-
phone is housed in a sturdy case, and is supplied with a
magnetic microphone hanger.
The extendible coiled cord
plugs into a jack on the bottom of the radio, and is secured to
the radio by a cable clamp.
In trunked mode, the radio can be programmed to originate
a call when the microphone is removed from the hanger, or to
terminate a call when the microphone is returned to the hanger.
In conventional mode, Channel Guard (an option) is dis-
abled when the microphone is removed from the magnetic
hanger allowing the operator to monitor the channel before
sending a message. Optional DTMF and desk microphones
are also available for other applications.
CARRIER CONTROL TIMER (CCT)
The Carrier Control Timer turns off the transmitter after the
microphone push-to-talk (PTT) switch has been keyed for a
pre-programmed time period. A continuous alert tone warns
the operator to unkey and then rekey the PTT to continue the
transmission. The timer can be set for 30 seconds to 7.5 min-
utes in 30 second increments. The timer can be enabled or dis-
abled for each channel.
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 through continuous digital coded squelch
(CDCSS) Channel Guard codes. Tone frequencies range from
67.0 Hz to 210.7 Hz. There are 83 standard programmable
digital codes.
The Channel Guard tone frequencies and digital codes are
software programmable. Tone frequencies and digital codes
can be mixed on each channel. They are listed in Table 1.
SQUELCH TAIL ELIMINATION (STE)
STE is used with tone and digital Channel Guard to elimi-
nate squelch tails. The STE burst is transmitted when the mi-
crophone PTT is released. The receiving radio decodes the
burst and mutes the receiver audio for 250 ms. This mute time
allows the transmission to end and mutes the squelch tail. The
radio looks for STE on the received signal both when the mi-
crophone is on or off hook. STE is enabled for transmit and/or
receive by PC programming the radio's personality.
PC PROGRAMMING OPTIONS
The radio is programmed using an IBM compatible per-
sonal computer equipped with an RS-232 connector. Option
TQ-3310 provides the RS-232 serial interface unit and the ca-
ble between the PC and the unit. An auxiliary power supply
for the unit is also included but is not needed to program the
radio.
Option TQ-3372 provides the radio programming cable be-
tween the PC interface unit and the radio microphone jack.
TMX-8825/MDX GE-MARC PC programming software op-
tion TQ-3344 is provided on 5.25 inch diskettes and TQ-4344
is provided on 3.5 inch diskettes.
NOISE SUPPRESSION KIT OPTION
Noise Suppression Kit Option PD1A (19A148539G1) is
available for installations having excessive alternator or
electrical noises present on the power cable that prohibit
proper radio operation. Refer to the interconnect diagram
for options.
DESK MOUNTING WEDGE
Desk mounting wedge option MAIL (19C851685G2) is
available for use with the AC power supply options when
using the radio as a base station. The wedge mounting
bracket mounts the radio with the control panel tilted up for
better accessibility to the radio controls.
REMOTE MOUNT OPTION
The Remote Mount Option (MA3K) provides for con-
trolling the main radio assembly remotely from the Front
Cap Assembly. The Front Cap is removed from the main ra-
dio assembly and mounted to a rear housing containing an
interface board (supplied with the option). A new front cap,
without any controls or displays, containing an interface
board is mounted to the main radio assembly. An 18-foot
system cable is normally supplied for use between the two
units.
AC POWER SUPPLIES
Two AC power supplies are available when equipping
the MDX GE-MARC radio for operation as a base station.
Option PS1C (19A704647P2) is a 117 VAC, 60 Hz
power supply. Option PS1D (19A704647P3) is a 120/240
VAC, 50/60 Hz power supply. Both supplies are available,
depending upon the application requirements.
OPTION CABLE
Option cable CD7Z (19C851585P14) is used to bring all
option connections from the System Board through the back
of the radio to the outside. This cable is required with all ex-
ternal options.
POWER CABLE
Eighteen
foot
power
cable
Option
CD9A
(19B801358P17) is available for installations requiring more
than the standard nine foot cable.
LBI-38960
EXTERNAL SPEAKER OPTIONS
The military specification external speaker options pro-
vide a five inch speaker in a LEXAN housing. Option LS1F
(19A149590P1) provides a dash-kit for the External
Speaker. Speaker cable option CC9M (19A149590P8) is
also required for operation of this option.
The radio's ten watt amplifier drives the speaker's four
ohm impedance.
EXTERNAL ALARM
External
Alarm
Horn
Relay
Option
SU1C
(19A705499P1) requires External Alarm ON/OFF switch
Option SU1F (19C851585P7). The relay option connects to
pin 13 of the option cable Option CD7Z. The relay can
sound the vehicle horn when a call is received. The alarm
switch is used to turn the horn relay on or off.
HORN ALERT OPTION
If the Horn Alert Option is present, the radio can be pre-
programmed to beep the vehicle horn when a call is received
(in trunked mode operation only).
To enable the Horn Alert Option, momentarily press the
MENU (MNU) key until ALARM appears in the display. (If
PHONE appears, press MNU again). Use the GROUP
UP/DOWN (G , G ) keys to toggle between Yes or No to
enable or disable the alarm.
If desired, after disabling the alarm, press the CLEAR
(CLR) key to leave the menu mode and return the display to
the current area/group. The alarm remains enabled on the
area/group selected in the display.
With the alarm enabled, when a call is received, the radio
first sounds a pulsed alert warning tone for three (3) seconds
and then begins blowing the horn five times (one second on,
three seconds off, for 20 seconds). Pressing the microphone
PTT during the pulsed alert tone prevents blowing the horn.
The horn alert remains enabled for subsequent calls.
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