NAT SM69 AA12S Series - Manual (Page 30)

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00
3.3
Operation Specifics
3.3.1 Radio Selection
TX Select Switch
VOX/TX Annunciator RX Select Switches
3.3.1.1 Receive
The AA12S is typically configured to select the RX audio from three transceivers and up
to four additional receivers.
The RX Select switches are white double-throw centre-off switches. Receiver audio can
be selected by setting the appropriate RX select switch to the down position.
Transceiver audio can either be selected by setting the appropriate RX select switch to
the up position, or as a function of the TX select switch. The transceiver that is selected
by the TX select switch is also automatically selected for receive. Receive/sidetone
audio for the selected COM is automatically provided.
When a switch is in the centre-off position, no transceiver/receiver audio is selected.
3.3.1.2 Transmit
The TX select switch is a 4-position rotary control that provides radio selection for up to
three transceivers and a PA. By selecting the desired transceiver and pressing the
external TX PTT switch, the AA12S is activated for transmit operation, connecting the
respective mic to the selected transceiver. The transceiver that is selected by the TX
select switch is also automatically selected for receive. The front panel annunciator will
illuminate green to indicate transmit operation (see section 3.1.3.)
TX selections are available only to the pilot and copilot. Activation of either TX PTT
input connects the user’s MIC to the selected COM, and activates the output PTT to the
selected COM. When PTT is pressed, all audio except the sidetone of the selected
COM and NAV inputs is removed from the headphone of the particular PTT user. The
sidetone of the active COM is provided from the COM radio.
The PA position provides PA mic audio and PA keyline to an external amplifier (e.g.
AA21, AA23, PA250) for use as either a Loudhailer or Passenger Address system.
A priority transmission feature allows the pilot to override the co-pilot.
Page 3-2 Oct 13, 2005
ENG-FORM: 806-0106.DOT
Amendment #1 Oct 14, 2005
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