AIRPLANE
OPERATIONS
MANUAL
NAVIGATION AND
COMMUNICATION
REVISION 36
2-18-15
Page
3
Code
01
AOM-145/1114
DIGITAL AUDIO PANEL CONTROLS AND INDICATORS
1 - MICROPHONE SELECTOR BUTTONS
í When pressed enables transmission and reception of radio
signals through the respective COM unit (COM 1, COM 2,
COM 3, HF).
í Simultaneous selection of more than one microphone selector
button is not possible. Pressing a different microphone selector
button will cause the previously selected button to be
deselected.
í A bar illuminates inside the button to indicate that it is pressed.
2 - AUDIO CONTROL KNOBS
í When depressed, turns on the associated COM/NAV audio.
í When rotated, provides volume control for the associated
COM/NAV audio.
3 - PASSENGER BUTTON
í When pressed enables the crew to make the speech to the
passenger cabin while simultaneously deselecting the
previously selected COM transmitter.
4 - EMERGENCY BUTTON
í When pressed in case of interruption of power supply to the
Digital Audio Panel, it automatically connects the microphone
to the emergency COM mic outputs and headphone unit to
COM and NAV audio.
í The captain is connected to COM 1 and NAV 1 and the copilot
to COM 2 and NAV 2. Observer radio communications
capability is lost.
5 - BOOM/MASK BUTTON
í Alternates selection between the boom (pressed) and the mask
(released) microphones.
6 - ID/VOICE BUTTON
í When pressed (ID position), NDB and VOR audio signals are
filtered in order to enhance morse code identification.
í When depressed (VOICE position), VOR/ILS audio signals are
filtered in order to reduce morse code signal, enhancing the
VOR/ILS voice associated messages (e.g., ATIS messages).
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