Northern Airborne Technology AA9x - Manual (Page 5)

AA9x Series Single Channel Audio Controller
SM56 Installation and Operation Manual
Section 1 Rev: 1.00 Issue 4 Page 1-1
ENG-FORM: 800-0113.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
AA9x Series Single Channel Audio Controller. All derivative product information shall be contained in the
applicable manual supplement, which may be obtained from NAT as required.
Review all notes, warnings and cautions.
1.2 Product Description
The AA9x series provide control for all aircraft audio, allowing selection of transmit and receive audio,
LIVE, KEYED, or VOX intercom, interface for an additional hand held transmit microphone (hand mic),
and pilot isolation/emergency operation.
Transmit and PA functions are controlled with a single rotary switch. Receive audio, ICS operations and
tape audio are controlled with toggle switches. Receive volume, ICS volume and ICS VOX squelch are
individually adjusted with rotary controls. Sidetone (S/T) level is adjustable internally and the AA97 also
has an individual RX level control for each transceiver.
1.3 Design Features
The AA9x series are Dzus rail mounted units with lighted faceplates. Transceiver interfacing is
accomplished through directly switched microphones. To ensure maximum radio compatibility, it has a
ground-referenced keyline that incorporates no diodes or other steering components.
Independent control is provided for each audio channel within the controller, allowing sidetone, ICS audio
and RX audio to be independently set.
Boom mic support is provided for the pilot and co-pilot, with both ICS and XMIT functions via cyclic or
yoke switching. In some models, a third ‘transmit capable’ boom mic is added. Live (Hot Mic) and VOX
ICS are also provided, with a ‘transparent’ function, allowing immediate transmission via this mode
without further control panel switching and immediate return to ICS operation on completion. The ICS
(intercom) function is achieved using dynamic noise reduction and active filtering. This provides the
clearest possible ICS audio under high ambient noise conditions by rejecting airframe and wind noise and
passing only voiceband information.
All audio, except the S/T of the radio in use and certain DIRECT AUDIO input signals, is muted during
transmit for clarity. ICS operation allows transmit during any ICS mode by using the transmit PTT switch.
All switches, relay contacts and external connections are gold plated for maximum reliability. Switches
and relays are sealed. G10-FR flame retardant circuit boards are postcoated for maximum moisture
resistance and corrosion prevention. Relays are sealed, high vibration rated (50g shock), dry nitrogen
filled units.