3COM AA12S User Manual

SM69

AA12S Series
Compact Audio Controller

INSTALLATION AND OPERATION MANUAL

REV 4.00 October 13, 2005

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

V1Y 4N7

Telephone [phone]

Facsimile [phone]

Copyright 2005 by Northern Airborne Technology

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Performed at factory

Periodically NAT will release manual amendments. In order to maintain the most
accurate and up to date manual these amendments should be carried out immediately
upon receipt and recorded on the following amendment record.

AMENDMENT RECORD

Amendment

Number

Amendment

Date

Section(s)

Changed

Date

Entered

Entered By

806-0001 Oct 14/05 1,3

Insert any Amendment Instruction sheets after this page.

Oct 13, 2005 Page ii

ENG-FORM: 820-0109.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

INSTALL_OPS
MANUAL AMENDMENT

Manual: SM69 (AA12S) Amendment #: 1
Document # SM69\Install_Ops\809-0001 Amendment Date: Oct 14, 2005

The purpose of this amendment is to change the Revision of the manual to 4.00 (to
reflect its status as a 2-part manual), and to correct a Direct Audio statement (removed
from Section 3.3.1, added to Section 1.2.1.

NB. This amendment can be performed on both Rev 1.00 OR Rev 4.00 of this manual.

Amendment Instructions:

1

1-1 and 1-2 Rev 1.00 or 4.00 1-1 and 1-2 Rev 4.00 Amendment # 1
3-1 to 3-4 Rev 1.00 or 4.00 3-1 to 3-4 Rev 4.00 Amendment # 1

2 Update the Amendment Record sheet at the front of the manual.

3 Insert this page into the manual after the Amendment Record sheet (page ii).

Manual Amendment ends after the following amended pages

Remove Pages Replace With Pages

Amendment # 1 Oct 14, 2005 Page 1

ENG-FORM: 809-0109.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Table of Contents

Section Title Page

1 Description

1.1 Introduction 1-1

1.2 General Information 1-1

1.2.1 Features 1-1

1.2.2 Installation Adjustments 1-1

1.3 Specifications 1-2

1.3.1 Electrical Specifications 1-2

1.3.2 Physical Specifications 1-4

1.3.3 Environmental Specifications 1-4

1.3.4 Unit Nomenclature 1-5

2 Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Installation Procedures 2-1

2.3.1 Warnings 2-1

2.3.2 Cautions 2-2

2.3.3 Notes 2-2

2.3.4 Cabling and Wiring 2-2

2.3.5 Post-Installation Checks 2-2

2.3.6 Adjustments 2-3

2.4 Continued Airworthiness 2-4

2.5 Accessories Required But Not Supplied 2-4

2.6 Installation Drawings 2-5

3 Operation

3.1 Introduction 3-1

3.2 General Information 3-1

3.2.1 Features 3-1

3.2.2 Installation Adjustments 3-1

3.3 Operation Specifics 3-2

3.3.1 Radio Selection 3-2

3.3.2 Intercom 3-3

3.3.3 PILOT ISO / NORM Modes 3-4

3.3.4 Entertainment Audio 3-4

3.3.5 Automatic Fail-safe 3-5

Oct 13, 2005 Page iii

ENG-FORM: 820-0109.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Section 1 Description

1.1 Introduction

Information in this section consists of the functional and operational procedures for the
AA12S Series Compact Audio Controllers.

The information in this manual is applicable to all models unless otherwise specified.

1.2 General Information

The AA12S is a compact Dzus-mounted audio controller with an integral 4-place stereo
voice-activated intercom. It provides intercom capabilities for the pilot, co-pilot and two
passengers (PAX). The AA12S accepts stereo music inputs from either portable or
fixed entertainment systems to produce high quality stereo headset output.

Radio functions include selectable transmit capability for pilot and co-pilot on 3 COM
radios and a PA. Receive audio selections include COM1, COM2, COM3, MKR, NAV,
ADF, and DME.

1.2.1 Features

All four mics have individual VOX gating. Each gate may also be activated with the
corresponding ICS keyline.

ICS muting is automatic during radio transmission.

The unit is supplied to suit a standard NAT bidirectional ICS audio TIE line for multi-unit
interface (configuration dependent). The crew and PAX are always connected except in
the case of Pilot ISO mode, when the pilot is disconnected from the ICS tie line.

If required, one or more receiver audio inputs may be configured at the factory prior to
ordering as (an) unswitched Direct Audio input(s). A new part number may be
assigned. Contact NAT Product Support for further information.

1.2.2 Installation Adjustments

The following audio levels can be adjusted at the time of installation, or during service
by an approved dealer, using individual level trimpots.

• Music Mute level • Sidetone level

• ICS Bass level • ICS Balance

• RX volume level • RX Balance

• Music Bass level • Music Balance

Oct 13, 2005 Page 1-1

ENG-FORM: 800-0107.DOT Amendment # 1 Oct 14, 2005

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

1.3 Specifications

1.3.1 Electrical Specifications

Power Supply

Input voltage 11-30 Vdc operating. Linear regulator with

reverse and over voltage protection.

Internal supply 11 Vdc

Nominal Lighting Voltage 27.5 Vdc @ 200 mA max (AA12S-001)

13.5 Vdc @ 400 mA max (AA12S-004)

Nom. Operating Voltages 27.5 Vdc @ 600 mA max

(one input for both) 13.8 Vdc @ 600 mA max

Maximum Operating 30.3 Vdc

Minimum Operating 11.0 Vdc

Note: The AA12S is not designed to operate under emergency electrical system

conditions for 14 Vdc operation.

Input Signals

Mic:

Quantity 4 (Pilot, Copilot, 2 Passengers)
Rated level 250 mVrms nominal (125 to 500 mVrms)
Impedance 150 Ohm ±10 %
Circuitry type unbalanced

TX Keyline:

Quantity 2 (Pilot, Copilot)
Rated level ground activates keyline, <20 mA source current

ICS Keyline:

Quantity 4 (Pilot, Copilot, 2 Passengers)
Rated level ground activates keyline, <1 mA source current

Receive Audio:

Quantity 7 (3 COM, 4 NAV)
Rated level 2.5 Vrms nominal (1.3 to 5.0 Vrms)
Impedance 1 kOhm ±10 % (1 to 3 kOhm for sidetone)
Circuitry type unbalanced

Music Inputs:

Quantity 2 (left channel, right channel)
Rated level 1.4 Vrms nominal (850 mVrms to 2.4 Vrms)
Impedance 11 kOhm ±10 %
Circuitry type unbalanced

Page 1-2 Oct 13, 2005

ENG-FORM: 800-0107.DOT Amendment # 1 Oct 14, 2005

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Bidirectional Signals

ICS TIE Channel:

Quantity 1
Rated level 340 mVrms nominal (170 to 680 mVrms)
Impedance 2 kOhm ±10 %
Circuitry type unbalanced

Output Signals

Phones:

Quantity 4 (Pilot, Copilot, 2 Passengers)
Rated level >5.5 Vrms (>100 mW, RX, ICS and music)
>0.7 Vrms (TX sidetone, adjustable)

1.5 Vrms nominal (Pilot ISO mode)
>0.2 Vrms (Automatic failsafe mode)
Impedance 300 Ohm ±10 %
Circuitry type transformer, unbalanced

Mics:

Quantity 4 (COM1, COM2, COM3 and PA)
Rated level 250 mVrms ±10 %
Impedance 150 Ohm nominal
Circuitry type direct throughline via relay

Keylines:

Quantity 4 (COM1, COM2, COM3 and PA)
Rated level <1 A
Circuitry type grounded relay contact

Audio Performance

As per RTCA DO-170 Product Classification 1a except where noted.

* Manufacturers Specification ** Exceeds DO-170 requirement

Rated Output Power (each stereo channel) 100 mW min. into 300 Ω

Audio freq. Response:

Receive ≤3dB down from 350 - 6000 Hz
Intercom ≤3dB down from 350 - 3000 Hz
ICS Tie ≤3dB down from 350 - 3000 Hz
Music ≤3dB down from 300 - 15000 Hz

(Music Bass control at mid setting)

Distortion ≤10%, ≤3 % typical (350 to 6000 Hz)

Input - Input crosstalk -37 dB max*

Input - Output crosstalk -55 dB max

Input - Mic crosstalk <200 µVrms*

Oct 13, 2005 Page 1-3

ENG-FORM: 800-0107.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

Audio noise -60 dB max**

Output Regulation ≤3 dB variance (350 to 6000 Hz)

Audio Communication Loud & Clear

ICS Volume controls <35 dB range*, 40 dB nominal

Music Volume controls <35 dB range*, 40 dB nominal

Receive Input impedance 1 kΩ ±10 %

Mic Input impedance 150 Ω ±10 %

Music Input impedance 11 kΩ ±10 %

ICS Tie Line 2 kΩ ±10 %

1.3.2 Physical Specifications

Width 4.95" (125.7 mm) max, behind panel

Depth 5.80" (147.3 mm) max, behind panel

Height 1.15" (29.2 mm) max

Weight 1.2 lb (0.50 kg) max

Mounting Dzus rail, four fasteners, 5.366" horizontal

spacing, and 0.750" vertical spacing

Faceplate Lighted panel is laser-engraved acrylic edge lit

with blue-white backlighting

Material/Finish Brushed aluminum with chromate conversion

Connectors One 25-pin female D-min connector with jackposts
One 44-pin male high-density D-min connector

with jackposts

Installation Kit AA12S-IKC

1.3.3 Environmental Specifications

Temperature -20 °C to +55 °C

Altitude 50,000 ft

Shock 6g/11ms, 20g/11ms

Safety of Flight requirements per RTCA DO-160D Environmental Conditions
DO-160D Env. Cat. [(A1)(D1)X]BXB[(SMB)(UF)]XXXXXXZBAXXXMXXXX

Page 1-4 Oct 13, 2005

ENG-FORM: 800-0107.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

1.3.4 Unit Nomenclature

Variants of the AA12S series Compact Audio Controllers are identified as follows:

AA12S-001

Unassigned Options

1.3.4.1 Unassigned Options

These portions of the designator may be assigned to future special options.

1.3.4.2 Lighting Voltage

This portion of the designator refers to the lighting voltage of the specific model.

001 = 28 Vdc lighting

004 = 14 Vdc lighting

End of section 1

Lighting Voltage

Oct 13, 2005 Page 1-5

ENG-FORM: 800-0107.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Section 2 Installation

2.1 Introduction

Information in this section consists of: unpacking and inspection procedures, installation
procedures, post-installation checks, and installation drawings.

2.2 Unpacking and Inspection

Unpack the equipment carefully and locate the warranty card. Inspect the unit visually
for damage due to shipping and report all such claims immediately to the carrier
involved. Note that each unit should have the following:

- AA12S Series Compact Audio Controller

- Warranty Card

- Operator’s Manual

- Release certification

Verify that all items are present before proceeding and report any shortage immediately
to your supplier.

2.2.1 Warranty

Complete the warranty card information and send it to NAT when the installation is
complete. If you fail to complete the warranty card, the warranty will be activated on
date of shipment from NAT.

Note: An appropriately rated facility, e.g. Certified Aircraft Repair Station, must install

this equipment in accordance with applicable regulations. NAT Ltd’s warranty is
not valid unless the equipment is installed by an authorized NAT Dealer. Failure
to follow any of the installation instructions, or installation by a non-certified
individual or agency will void the warranty, and may result in a non-airworthy
installation.

2.3 Installation Procedures

2.3.1 Warnings

Do not bundle any lines from this unit with transmitter coax lines. Do not bundle any
audio or DC power lines from this unit with 400 Hz synchro wiring or AC power lines. Do
not position this unit or wiring from this unit next to any device with a strong alternating
magnetic field such as an inverter, or significant audio interference will result.

Oct 13, 2005 Page 2-1

ENG-FORM: 805-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

2.3.2 Cautions

In all installations, use shielded cable exactly as shown and ground as indicated.
Significant ground loop and noise problems may result from not following these
guidelines.

The shielding and routing of the MIC and ICS TIE LINES used in the AA12S installation
is very critical and poor performance of the aircraft audio system will result if these
issues are not handled properly.

The operation of the VOX intercom can be severely degraded by the quality and type or
mix of microphones used in the aircraft. If one user has a very 'hot' microphone, it will
present more electrical signal to the VOX circuit and the VOX SQUELCH will have to be
set to quiet this microphone. The other microphones may not be able to generate
enough electrical energy to overcome this VOX SQUELCH setting, and will break up or
not be heard at all.

2.3.3 Notes

Audio performance can be impaired by the introduction of airframe electrical noise at
the headset jack locations. For best results, all headset jacks should be fully isolated
from the airframe.

2.3.4 Cabling and Wiring

All unshielded wire should be MIL-W-22759 or equivalent. For shielded wire
applications, use Tefzel MIL-C-27500 shielded wire with solder sleeves (for shield
terminations) to make the most compact and easily terminated interconnect. Follow the
wiring diagrams in Section 2.6 as required.

Allow 3 inches from the end of the wire to the shield termination to allow the hood to be
easily installed. Note that the hood is a ‘clamshell’ hood, and is installed after the wiring
is complete.

All wiring should be at least 22 AWG, except power and ground lines, which should be
at least 20 AWG. Ensure that all ground connections are clean and well secured.

2.3.5 Post-Installation Checks

If any preset requires adjustment, be sure this is carried out before the aircraft leaves,
and that the unit and its mating connector are secured before departure. Make all
required log book entries, electrical load, weight and balance amendments and other
paperwork as required by your local regulatory agency.

Page 2-2 Oct 13, 2005

ENG-FORM: 805-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

2.3.5.1 Voltage/Resistance Checks

Check the following:

a) P101 pin <1> for avionics buss voltage.

b) P101 pin <16> for continuity to ground.

c) P101 pins <9> <10> <11> and <12> for continuity to ground when the relevant

switch is closed. (Also check pins <13> and <14> if switches are installed in
these positions.)

d) P301 pin <5> for avionics lighting bus voltage relative to ground (with lighting on).

e) P301 pin <17> for continuity to ground.

2.3.5.2 Power On Checks

a) Install the AA12S and power up the ship’s systems. Turn on the radios and

accessories required for the system.

b) Check for correct radio audio and adjust for acceptable level.

c) Run through all installed functions, and check the ICS and TX functions for all

users. Refer to Section 3 for specific operation details.

Note: Significantly different headsets may have different mic characteristics.

d) If any preset requires adjustment, be sure this is carried out before the aircraft

leaves, and that the unit and its mating connector are secured before departure.
Make all required log book entries, electrical load, weight and balance
amendments and other paperwork as required by your local regulatory agency.

2.3.6 Adjustments

The internal adjustments that can be varied are located along the sides of the unit and
are accessed through necessary switches and trimpots.

Note: The unit is shipped from the factory with all internal adjustments set to the normal

test levels. Once installed in the aircraft, it may be desirable to change some of
these settings to best suit the local operating environment.

2.3.6.1 Left Side Adjustments

The adjustments found on the left side of the unit are:
ICS BAL R L, which controls the ICS Balance;

BAL

ICSICS

BASS

MUSIC

MUTE

ICS BASS, which controls the ICS bass level;

RL

and MUSIC MUTE, which controls the Music mute level.

Oct 13, 2005 Page 2-3

ENG-FORM: 805-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

2.3.6.2 Right Side Adjustments

The adjustments found on the right side of the unit
are:
TX S/T, which controls the sidetone level;
RX BAL R L, which controls the RX Balance;
RX VOL, which controls the RX volume level;

RX

BASS

VOLBAL

BAL

RLLR

TX

S/T

MUSIC

MUSIC

RX

MUSIC BASS, which controls the Music Bass level;
and MUSIC BAL R L, which controls the Music balance.

Upon satisfactory completion of all performance checks, make the required log
entries and complete the necessary Regulatory Agency paperwork before
releasing the aircraft for service.

2.4 Continued Airworthiness

Maintenance of the AA12S is ‘on condition’ only. Periodic maintenance of this product is
not required.

2.5 Accessories Required But Not Supplied

Installation kit p/n AA12S-IKC (crimp) is required to complete the installation. The kit
consists of one 44-Pin D-min Female Crimp Kit (NAT Part # D44SL-IKC) and one 25-Pin
D-min Male Crimp Kit (NAT Part # D25PL-IKC).

The D44SL-IKC consists of:

Quantity Description NAT Part #

1 D-min 44 Socket Housing 20-20-044
44 Mini D Crimp Socket 20-26-703
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 25 pin Connector Hood 20-29-026

The D25PL-IKC consists of:

Quantity Description NAT Part #

1 D-min 25 Pin Housing 20-11-025
25 MS Crimp Pin 20-26-891
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 25 Pin Connector Hood 20-29-026

* Use as required.

Page 2-4 Oct 13, 2005

ENG-FORM: 805-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

2.6 Installation Drawings

DRAWING REV. DESCRIPTION TYPE SERIAL #

AA12S\001\403-0 1.10 AA12S Compact Audio Controller Interconnect All
AA12S\001\405-0 1.10 AA12S Compact Audio Controller Connector Map All
AA12S\001\905-0 1.10 AA12S Compact Audio Controller Faceplate All
AA12S\001\922-0 1.10 AA12S Compact Audio Controller Mech. Installation All

Section 2 ends after these Drawings

Oct 13, 2005 Page 2-5

ENG-FORM: 805-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

TX

S/T

BAL

ICS ICS

LR

BASS

BAL

R L

MUTE

MUSIC

MUSIC

BASS

MUSIC

RX

RX

BAL VOL

R L

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

Section 3 Operation

3.1 Introduction

Information in this section consists of the functional and operational procedures for the
AA12S Series Compact Audio Controllers.

The information in this manual is applicable to all models unless otherwise specified.

3.2 General Information

The AA12S is a compact Dzus-mounted audio controller with an integral 4-place stereo
voice-activated intercom. It provides intercom capabilities for the pilot, copilot and two
passengers (PAX). The AA12S accepts stereo music inputs from either portable or
fixed entertainment systems to produce high quality stereo headset output.

Radio functions include selectable transmit capability for pilot and copilot on 3 COM
radios and a PA. Receive audio selections include COM1, COM2, COM3, MKR, NAV,
ADF, and DME.

3.2.1 Features

All four mics have individual VOX gating. Each gate may also be activated with the
corresponding ICS keyline.

ICS muting is automatic during radio transmission.

The unit is supplied to suit a standard NAT bidirectional ICS audio TIE line for multi-unit
interface (configuration dependent). The crew and PAX are always connected except in
the case of Pilot ISO mode, when the pilot is disconnected from the ICS tie line.

3.2.2 Installation Adjustments

The following audio levels can be adjusted at the time of installation, or during service
by an approved dealer, using individual level trimpots.

• Music Mute level • Sidetone level

• ICS Bass level • ICS Balance

• RX volume level • RX Balance

• Music Bass level • Music Balance

Oct 13, 2005 Page 3-1

ENG-FORM: 806-0106.DOT Amendment #1 Oct 14, 2005

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

3.3 Operation Specifics

3.3.1 Radio Selection

VOX/TX Annunciator

RX Select Switches

TX Select Switch

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

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

at

o

3.3.1.3 VOX/TX Annunciator

The VOX/TX Annunciator is a bicolour LED that indicates the intercom status.

During VOX activity, the annunciator LED is illuminated red. If TX is keyed with no ICS
or sidetone, the annunciator LED is illuminated green. If TX is keyed with mic or
sidetone, the combination of red and green will cause the LED to appear amber.

Note: If the LED is still illuminated green after transmission is concluded, this indicates

a possible stuck mic.

3.3.2 Intercom

ICS VOL/VOX Squelch Control

VOX/TX Annunci

r

The VOX and ICS VOL control is a fluted concentric knob, with the ICS volume on the
centre knob, and the VOX control on the outer knob.

3.3.2.1 VOX Control

The VOX control is used to set the level of audio required to activate the microphones.

The AA12S provides three modes of intercom operation, selected by the position of the
VOX control.

LIVE ICS When the VOX control is positioned fully counter-clockwise (ccw), all mics

will be live, and any sound picked up by the microphone(s) will be
processed by the ICS system

KEYED ICS When the VOX control is positioned fully clockwise (cw), the intercom will

be in a keyed-only mode.

VOX ICS When the VOX control is positioned between fully cw and fully ccw, the

intercom is in VOX mode. To establish the VOX threshold, rotate the
control ccw until the LED turns red, and then rotate the control cw until the
LED goes dark. Continue turning the control cw until the desired voice
sensitivity is set.

Oct 13, 2005 Page 3-3

ENG-FORM: 806-0106.DOT Amendment #1 Oct 14, 2005

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

AA12S Series Compact Audio Controller Manual SM69 Rev. 4.00

3.3.2.2 ICS Volume Control

The ICS VOL control, which has a line to mark rotational position, is at minimum volume
when fully ccw. As the knob is rotated cw, the ICS volume for crew and PAX increases.

The ICS is muted during transmit operations.

3.3.3 PILOT ISO / NORM Modes

Pilot Isolate Switch

The PILOT ISO/NORM control is a red, two-position toggle switch that allows selection
of either NORM (Normal) or PILOT ISO (Pilot Isolate).

In NORM mode (default) everyone on the system can talk to each other, listen to music,
and hear all selected radio audio.

The PILOT ISO mode separates the pilot from the intercom network, allowing
confidential radio communications without interference from the copilot or passenger
intercom or music, while maintaining complete control of all the radio functions of the
audio panel. The copilot and passengers retain normal intercom and music functions.

Note: In PILOT ISO mode, the receive/sidetone levels may require adjustment at the

audio source.

3.3.4 Entertainment Audio

The AA12S accepts stereo music input from portable entertainment units, CD players or
other integrated on-board systems. The stereo output delivers music to stereo, or
standard monaural, general aviation headsets (installation dependent).

Music muting occurs during any radio or intercom activity.

Page 3-4 Oct 13, 2005

ENG-FORM: 806-0106.DOT Amendment #1 Oct 14, 2005

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM69 Rev. 4.00 AA12S Series Compact Audio Controller Manual

3.3.5 Automatic Fail-safe

In the event of a power failure, automatic fail-safe operation will be activated. This
routes the pilot’s phones, mic audio, and mic PTT directly to the COM radio selected by
the position of the TX rotary selector switch, and selected audio inputs. Copilot and
passengers will have no ICS, music, or receive functions.

In the unlikely event of an AA12S circuit failure that results in a communication failure,
the automatic fail-safe mode can be enabled by pulling the AA12S circuit breaker.

Note: In Automatic Fail-Safe mode, the receive/sidetone levels may require adjustment

at the audio source.

The pilot should confirm that all aspects of Automatic Fail-Safe operation are
working before accepting the aircraft into service.

End of section 3

Oct 13, 2005 Page 3-5

ENG-FORM: 806-0106.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.