AA21-406 PA Controller
SM34 Installation and Operation Manual Supplement
SM Supplement Rev: 1.11
Mar 24, 2009
Page 1
This supplement contains installation and operation information that is unique to the AA21-406 PA
Controller. Installation and operation information common to the AA21-400 base unit can be found in the
SM34
Installation and Operation Manual.
Section 1 Description
The AA21-406 provides control for an aircraft’s internal and external PA systems. Audio inputs include
microphone, receive audio or CD input. Receive audio or PA mic input is selectable on the front panel.
Adjustable sidetone is provided for the mic input. A PA output with adjustable level is available. Thermal
and short circuit protection are provided for the internal speaker output electronics. Wail or yelp siren is
selectable on the front panel and activated by enabling the siren keyline.
Figure 1: AA21-400
Figure 2: AA21-406
1.1 Specification
Changes
The AA21-406 is identical to the AA21-400 with the following exceptions:
a)
The speaker output is replaced with a CABIN PA MIC output.
b)
An INT/EXT discrete function is added.
c)
The POWER switch is removed. The unit is hard-wired to be on.
d)
The faceplate backlighting is 5 Vdc.
e)
Changes to the faceplate text can be found by comparing Figure 1 to Figure 2.
ENG-FORM: 810-0111.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
23-31-90
The document reference is online, please check the correspondence between the online documentation and the printed version.
