Northern Airborne Technology AA224 series Installation And Operation Manual - page 44
AA24/AA25 Series Single User Audio Controller Manual
SM18 Rev 4.00
3.3.2
Receiver/Transceiver Selection
The Receiver/Transceiver audio is selected from a double row of color-coded toggle
switches. Receiver switch bats are blue, and transceiver switch bats are white. To
connect the desired radio to the headphones, the relevant switch is toggled upwards.
On the AA25, independent volume controls are provided for the transceivers and the
first two NAV aids.
3.3.3 Volume
Control
The Volume control is a dual concentric knob.
3.3.3.1
ICS Volume Control
The inner knob of the dual control is ICS VOL and controls the intercom volume for all
headsets. An internal trimpot sets the minimum level. With ICS VOL set fully ccw
intercom volume will be at a minimum. As the operator rotates the control cw, intercom
volume will increase.
In multiple station systems, the ICS volume adjusts only the local ICS audio level.
3.3.3.2
RX Volume Control
The outer knob of the dual control is RX VOL and controls the RX volume for all
selected radios. With RX VOL fully ccw, volume will be at a minimum. As the operator
rotates the control cw, volume will increase.
3.3.4
VOX Mode Control
The VOX Control selects the mode of operation of the intercom mic. When the control
is in the centre of its range, the intercom is in the VOX mode (voice activated). As the
control is rotated counterclockwise, the system becomes more sensitive, until in the fully
counterclockwise position it is in LIVE mode (on constantly). As the control is rotated
clockwise, the sensitivity decreases, until at the fully clockwise position it is in PTT
mode (activated by cyclic or foot switch closure).
3.3.5
Audio Alerting Functions
The user receives audio alerting signals connected to the Direct Audio under all
operating conditions of the AA24/AA25.
End of Section 3.0
Page 3-2
Nov 21, 2003
ENG-FORM: 806-0105.DOT
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