OPERATION
Transmitting
When a transmitter is keyed, the active transceiver
MIC key annunciator blinks approximately once per sec-
ond. A white TX indication appears next to the active
COM frequency on both the PFD and the MFD during
transmission.
NOTE: Audio level of the COM radio(s) is con-
trolled by the COM volume controls located on
both the PFD and MFD (see the VHF NAV/COM
Pilot's Guide).
COM SWAP
A remotely mounted switch can be used to transfer the
active transceiver between COM1 MIC and COM2 MIC.
Pressing the switch has no effect if COM3 is the active
transceiver.
OPTIONAL COM MUTING
COM muting on receive and COM muting on trans-
mit options can each be disabled if desired. Contact a
Garmin-authorized service center for details.
COM Muting on Receive
When COM muting on receive is enabled, all second-
ary COM audio is muted during detection of received pri-
mary COM audio.
NOTE: If COM muting on receive option is
enabled, only primary COM radio reception is
recorded by the digital clearance recorder.
COM Muting on Transmit
When COM muting on transmit is enabled, all sec-
ondary COM audio is muted during transmission over the
primary COM radio.
6A-6
TELEPHONE INTERFACE
The GMA 1347 contains a dedicated telephone inter-
face that is closely linked to the ICS operation. It is con-
trolled by the TEL key. See Table 6A.3.3 for a summary
of the telephone distribution and the various ICS isolation
modes.
SPLIT COM FUNCTION
Pressing the COM 1/2 key selects the split COM func-
tion. During split COM operation, the COM1, COM1
MIC, COM2 and COM2 MIC keys are active.
When the COM 1/2 key is selected, COM1 is used by
the pilot for transmission and COM2 is used by the copi-
lot. The COM1 MIC annunciator blinks when the pilot' s
microphone is keyed and the COM2 MIC annunciator
blinks when the copilot' s microphone is keyed.
In this mode, both the pilot and the copilot can trans-
mit simultaneously over separate radios. The pilot can
still monitor COM3, NAV1, NAV2, DME, ADF, AUX and
MKR audio as selected, but the copilot is only able to
monitor COM2.
Split COM mode is cancelled by pressing the COM 1/2
key again.
Garmin G1000 Audio Panel Pilot's Guide
NOTE: The ringer to the TEL channel is muted
during COM radio transmissions.
NOTE: Split COM performance varies significantly
across installations and is affected by both the
distance between the antennas and the separa-
tion of the tuned frequencies.
190-00378-02 Rev. A