G M A 3 4 0 |
A U D I O P A N E L |
P I L O T ’ S |
G U I D E |
® |
Front Panel Controls
MKR BCN
ICS
1.Marker Beacon Lamps
2.Marker Beacon Receiver Audio Select/Mute Button
3.Marker Beacon Receiver Sensitivity Indicator LED.
4.Marker Beacon Receiver Sensitivity Selection Button
5.Unit On/Off, Pilot Intercom System (ICS) Volume
6.Pilot ICS Voice Activated (VOX) Intercom Squelch Level
7.Copilot and Passenger ICS Volume Control (Pull out for Passenger
Volume)
8.Copilot/Passenger VOX Intercom Squelch Level
9.Crew Isolation Intercom Mode Button
10.Pilot Isolation Intercom Mode Button
11.Passenger Address (PA) Function Button
12.Speaker Function Button
13.Transceiver Audio Selector Buttons (COM1, COM2, COM3)
COM/ 14. Transmitter (Audio/Mic) Selection Buttons
NAV 15. Split COM Button
16.Aircraft Radio Audio Selection Buttons (NAV1, NAV2, DME, ADF)
17.Annunciator Test Button
18.Locking Screw Access
19.Photocell - Automatic Annunciator Dimming
1
On, Off, and Fail-Safe Operation
The GMA 340 is powered off when the left small knob (5) is rotated fully CCW into the detent. To turn the unit on, rotate the knob clockwise past the click. The knob then functions as the pilot ICS volume control. A fail-safe circuit connects the pilot’s headset and microphone directly to COM1 in case power is interrupted or the unit is turned off.
Lighting
LED button annunciator and marker beacon lamp intensity are controlled automatically by a built-in photocell on the front panel. Nomenclature backlighting is controlled by the aircraft dimmer buss.
Transceivers
NOTE
Audio level is controlled by the selected COM radio volume controls.
Selection of either COM1, COM2, or COM3 for both MIC and audio source is accomplished by pressing either COM1 MIC, COM2 MIC, or COM3 MIC (14). The active COM audio is always heard on the headphones.
Additionally, each audio source can be selected independently by pressing COM1, COM2, or COM3 (13). When selected this way, they remain active as audio sources regardless of which transceiver has been selected for microphone use.
When a microphone is keyed, the active transceiver’s MIC button LED blinks approximately once per second to indicate that the radio is transmitting.
Split COM
Pressing the COM 1/2 button (15) activates the split COM function. When this mode is active, COM1 is dedicated solely to the pilot for MIC/audio while COM2 is dedicated to the copilot for MIC/audio. The pilot and copilot can simultaneously transmit in this mode over separate radios. Both pilots can still listen to COM3, NAV1, NAV2, DME, ADF, and MKR as selected. The split COM mode is cancelled by pressing the COM 1/2 button a second time.
When in the split COM mode the copilot may make PA announcements while the pilot continues using COM1 independently. When the PA button is pressed after the split com mode is activated, the copilot’s mic is output over the cabin speaker when keyed. A second press of the PA button returns the copilot to normal split COM operation.
2
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