Northern Airborne Technology 3110 - Manual (Page 60)

3110-100 Audio Control Panel Manual SM3110 Rev. 4.00
headphone. The CVR output contains the pilot headphone audio, which is a sum of the
tranceiver's audio and the aural warning audio.
Without power, the speaker, receiver/transmitter selections, and all other front panel
operations are effectively disabled.
When power is restored to the unit, it will return to the last known transmit select
configuration and annunciator status.
3.4.2
Oxygen Mask Mode
An external switch is used to switch between the Boom Mic and Oxygen Mask Mic
audio sources.
Selecting the Oxygen Mask Mode deactivates any Aural Warning mute that has been
previously activated. Oxygen Mask Mode also enables interphone audio to be heard
over the cockpit speaker.
3.4.3
Cabin Call Tone
A momentary external Cabin Call Tone switch can be connected to the 3110-100 to
indicate to the pilot that the service interphone headset operators wish to communicate
with the cockpit.
Each activation of the switch will cause the Cabin Call Tone to be played once to the
pilot, the service headphone, and to the cockpit speaker outputs.
3.4.4
Speaker Mute (AUX MUTE)
An external momentary switch may be connected to the 3110-100 to mute all audio,
including aural warnings, to the cockpit speaker. (The pilot headphone audio remains
unmuted.)
Audio to the speaker may be restored in four ways: by a second action of the switch; by
selecting and then deselecting Oxygen Mask Mode; by removing and then restoring
power to the unit; or by activating and then deactivating emergency mode (see section
3.4.1).
The 3110-100 can be connected to an external annunciator to indicate that speaker
mute has been activated.
3.4.5
Aural Warning Volume
An external switch may be connected to the 3110-100 to allow selection of high or low
aural warning volume (for all aural warning audio).
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ENG-FORM: 806-0106.DOT
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