Garmin GMA 35 Installation Manual page 31

NOTE
Depending on configuration and sometimes COM system wiring, other transceivers may
be muted during transmit. Also, the audio panel may mute the speaker during PTT.
4. Move the headset to the copilot's headset jacks and verify that any one of the installed transceivers
(testing each is not necessary) receives and transmits copilot mic properly as above.
3.7.3 Verify Audio from Installed Receiver and Alert Sources
1. Connect a headset to the pilot's headset output and mic input jack (depending on configuration and
ICS mode, copilot or passenger positions may not hear all of these sources).
2. Verify each installed receiver (NAV/ADF/DME) can be heard when selected (use test signal gener-
ators/transmitters when necessary).
3. Verify each installed unswitched (alert) source can be heard when the source is instructed to play a
simulated alert/message.
3.7.4 Verify Speaker Output (if installed)
1. Select the speaker output and verify any one transceiver or receiver is heard clearly.
2. Verify that any one unswitched (alert) source is heard clearly in the speaker (depending on config-
uration, these may be heard in the speaker regardless of speaker selection).
3. Initiate PA (Passenger Address) mode and verify that from both the pilot and copilot position the
crew position that is pressing PTT has their mic delivered to the speaker clearly.
NOTE
If a loud squeal is heard while testing PA, it is because there is too much acoustic feedback
between the speaker and the mic. If they cannot be placed further apart, a lower volume
configuration should be used. In some installations, there is insufficient distance between
the speaker and crew seat positions for PA to speaker to reliably operate. In these
conditions, the "PA to speaker" volume can be set very low and PA audio will still be
delivered to the headsets.
3.7.5 Verify ICS (Intercom System) Operation
1. Place the audio panel into all ICS mode (refer to the applicable pilot's guide) so that all ICS
positions hear all others.
2. Deselect or turn off other audio sources (MKR, transceivers, receivers, alerts).
NOTE
Some configurations may mute passenger intercom audio to crew when aircraft audio is
present.
3. From the pilot headset position, verify the pilot, copilot, and all passenger mic inputs can be heard
in the pilot's headset when speaking into the mic input under test (adjust pilot ICS volume if
necessary).
4. Speak into the pilot's mic and verify that pilot mic audio is heard in the copilot headset (adjust
copilot ICS volume if necessary) and in each passenger headset (adjust passenger ICS volume if
necessary).
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GMA 35/35c Installation Manual
Page 3-5