Com/Vor/Ils/Digital Audio - Garmin GIA 63 Installation Manual

4.6 COM/VOR/ILS/Digital Audio

4.6.1 COM/VOR/ILS/Digital Audio Function and Emergency Mode
Activation of COM MIC KEY enables COM MIC AUDIO and causes the transceiver to transmit.
500Ω COM AUDIO and 500Ω VOR/ILS AUDIO are 100 mW audio outputs that are intended to drive a
headset or an audio panel. Digital audio outputs from the GMA 1347 are 3.87 Vrms into 150 ohms.
Momentarily depressing the COM REMOTE TRANSFER button toggles the active and standby COM
frequencies. Momentarily depressing the VLOC REMOTE TRANSFER button toggles the active and
standby VLOC frequencies.
The COM REMOTE TRANSFER input may be used for EMERGENCY operation of the COM
transmitter. If the remote transfer switch is depressed for two seconds, the active COM frequency
changes to 121.50 MHz. Once the emergency frequency is activated through COM REMOTE
TRANSFER, the GIA 63(W) ignores inputs from the front panel controls for COM selections only. The
pilot may exit this independent mode—restoring COM selection control to the front panel knobs and
buttons—by momentarily depressing the COM REMOTE TRANSFER switch.
When TRANSMIT INTERLOCK is active, the GIA 63(W) COM receiver sensitivity is decreased. This
input is intended to reduce interference from other transmitters in the aircraft. The TRANSMIT
INTERLOCK input should be connected to the PTT input of other transmitters in the aircraft. If
connected to multiple PTT inputs, these connections must include diode isolation or multiple radios
transmit simultaneously.
For digital audio installations, all of this information is transferred in the digital audio data stream.
4.6.2 Com/VOR/ILS/DIGITAL Audio Electrical Characteristics
4.6.2.1 Com Mic Key
Pin Name
COM MIC KEY
INACTIVE: 10 ≤  V in ≤  3 3VDC or Rin ≥ 100kΩ
ACTIVE: Vin ≤ 1.9VDC with ≥  7 5 uA sink current, or Rin ≤ 375Ω
Sink current is internally limited to 200 uA max for a grounded input
4.6.2.2 Com Mic Audio, Intercom Mic Audio
Pin Name
INTERCOM MIC IN HI
INTERCOM MIC IN LO (GROUND)
COM MIC AUDIO IN HI
COM MIC AUDIO IN LO (GROUND)
COM MIC AUDIO and INTERCOM MIC each have a 520 Ω AC input impedance and supply the
microphone with a 9 V bias through 620 Ω.
COM MIC AUDIO is set in the factory for 275 mV
The microphone gain adjustment is accessible through the top cover.
Page 4-18
Revision H
Connector
P601
Connector
P601
P601
P601
P601
to modulate the transmitter at 80% nominally.
RMS
GIA 63/GIA 63W Installation Manual
Pin I/O
4 In
Pin I/O
5 In
6 --
7 In
8 --
190-00303-05