User's Manual

3-4
3.10 MIC 1, 2 AND 3 - PINS 3, 6 AND 9
The microphone input signals shall be connected using shielded wire with the shield connected to ground
(pin 1 or 14). It is recommended for best results to leave the other end of the shield floating to prevent
ground currents unless you are connecting to an audio panel with floating hi and lo inputs (like the
Technisonic A710 or A711 series) in which case the shield must be connected to the lo input.
3.11 AUDIO 1, 2 AND 3 - PINS 4, 7 AND 10
Audio outputs 1, 2 and 3 are 600 ohms impedance against ground. The output power is 500 mW
maximum.
3.12 PTT 1, 2 AND 3 - PINS 5, 8 AND 11
The PTT lines should be floating when in receive and grounded for transmit. The input has a pull up resistor
to 5 volts. Connecting an audio panel which wishes to see more, may result in no receive audio. Connect a
1N4006 diode in series with the cathode towards the audio panel in this case.
3.13 TX DATA AND RX DATA - PINS 12 AND 13
These are an RS-232 serial port for the RC-6000 remote control head if installed. Consult the RC-6000
installation manual for details.
3.14 CHANNEL UP AND CHANNEL DOWN - PINS 16 AND 17
These pins can be used to scroll up and down through the zone/channel/mode/talk group selections for the
band currently displayed on the screen. The inputs normally floating are grounded to activate. Two push
buttons or a center off, SPDT, spring loaded toggle switch are typically used on these inputs.
3.15 LH DATA, SB9600 BUSY, OPTB+, CTS OUT, BOOT DIN, RTSBIN AND RS232DIN - PINS 18 THROUGH
24
These pins are used for programming or updating the transceiver using Motorola Radio Service Software
(RSS™) or encryption key loading and are generally left unconnected. However, if it is desirable to update
the radio without removing it from the aircraft, these lines can be run to a 25 pin D male connector located
on the panel where a laptop computer can plug in. Use the same pin numbers so the programming cable
described in section 2 can be used (minus the power pins).
3.16 PANEL BACKLIGHTING - PINS 25
Connect to aircraft panel dimming bus. The transceiver comes with either 28 VDC or 5 VAC backlighting
circuits. Check the label on the side of the transceiver before applying power.
3.17 POWER JUMPER
The radio must be turned on manually each time the avionics bus is switched on. If it is desired that the
radio comes on with the radio master in the aircraft, remove the right side panel from the radio and install a
0.1” jumper across JP1 (two pins) near the rear of the radio on the right side of the MCU board. If you
attempt to turn off the radio with the jumper installed, it will just come back on again in 5 seconds.