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.