Northern Airborne Technology AA20 - Manual (Page 27)

AA20 Series PA/Siren System
SM33-1 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-1
Section 3 Operation
3.1 Introduction
Information in this section consists of functional and operational procedures for the AA20 Series PA/Siren
System.
3.2 General Information
The AA20 PA/Siren System provides a central adjustment for internal and/or external aircraft paging
functions. The AA20 is a self-contained mixer/amplifier which directly drives the cabin or external
speaker(s). When turned on, the system is ready for operation and will accept audio feeds or a
microphone input. An internally generated siren is also available and adjustable through the side of the
controller. When the AA20 is turned on, a POWER KEY signal is generated. This signal is used to turn on
the PA amp (if connected in system). The high current DC power to operate the PA110/220 is supplied by
the aircraft.
3.3 Controls and Indicators
3.3.1 Power Up
To activate the AA20 PA/Siren system, flip the POWER toggle switch up to the ON position. The LED
adjacent to the switch should illuminate.
Power Switch Indicator LED
3.3.2 Function Switch
The Function Switch is used to select the appropriate operational mode for the unit. These modes vary
depending on the unit under consideration and are listed below.
Function Switch
Note: PA audio has priority in the AA20 system and it will be heard even if the panel switch is selected
to RADIO or TAPE.
ENG-FORM: 806-0111.DOT
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