Northern Airborne Technology AA20-431 - Manual (Page 6)

SM22 Rev. 4.10 AA20-431 Cabin PA System Manual
Section 1.0 Description
1.1 Introduction
This manual contains information on the AA20-431 Cabin PA System. All derivatives
will be covered by manual supplements which can be obtained from NAT as required.
Information in this section consists of purpose of equipment, features and specifications.
1.2 Purpose of Equipment
The AA20-431 is a passenger announcement and entertainment system, capable of
providing a 30 W/8
Ω speaker output for in flight music, messages and advisory tones.
The system also provides eight 150 Ω headset outputs for use in operational
environments where it is not practical to use the speaker output.
The AA20-431 PA controller provides central adjustment for all the PA and music audio
to the passengers. Automatic chime before announcements and soft music muting are
standard features.
1.3 Features
The AA20-431 accepts music inputs from either portable cassette tape/CD players or
remote CD changers/am/fm cassette players. The left and right music inputs are
summed internally.
Music audio will mute and chime will activate prior to cabin pages; this allows for un-
distracted passenger attention. ‘Seat Belt’ and ‘No Smoking’ sign interlocks energize
the chime circuit when enabled and disabled. The Microphone input has an adjustable
sidetone amplifier, which provides ‘PA sidetone’ to the audio controller.
A +3 dB switch input allows the output level to change to suit aircraft operating
conditions.
The AA20-431 features Thermal and Overload protection circuits. These circuits
provide the internal circuitry with protection from over-voltage, over-current and high
temperature conditions.
Apr 21, 2004 Page 1-1
ENG-FORM: 800-0107.DOT
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