Northern Airborne Technology AA83-001 User Manual rev.4.00

SM09-2A

AA83-001
InterMUSIC™ Stereo Intercom System
Serial No. 2939 and later

INSTALLATION AND OPERATION MANUAL

REV 4.00 February 8, 2006

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

V1Y 4N7

Telephone [phone]

Facsimile [phone]

Copyright 2006 by Northern Airborne Technology

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

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

Note: Revision 4.00 is the first public release of this document

Amendment

Date

Section(s)

Changed

Date

Entered

Entered By

Insert any Amendment Instruction sheets after this page.

Feb 8, 2006 Page ii

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

Table of Contents

Section Title Page

1 Description

1.1 Introduction 1-1

1.2 Purpose of Equipment 1-1

1.3 Features 1-1

1.3.1 Stereo & Intercom Special Features 1-1

1.3.2 Communication Functions 1-1

1.4 Specifications 1-2

1.4.1 Electrical Specifications 1-2

1.4.2 Physical Specifications 1-4

1.4.3 Environmental Specifications 1-4

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 Cabling and Wiring 2-2

2.3.4 Adjustments 2-3

2.3.5 Mechanical Installation 2-3

2.3.6 Post-Installation Checks 2-5

2.4 Continued Airworthiness 2-6

2.5 Accessories Supplied 2-7

2.6 Installation Drawings 2-7

3 Operation

3.1 Introduction 3-1

3.2 General Operation 3-1

3.2.1 Stereo & Intercom Special Features 3-1

3.2.2 Communication Functions 3-1

3.2.3 Important Operating Considerations 3-2

3.2.4 Installation Adjustments 3-2

3.3 Controls and Indicators 3-2

3.3.1 ICS VOL/PILOT VOX 3-2

3.3.2 MUSIC VOL/COPILOT VOX 3-3

3.3.3 VOX Operation 3-3

Feb 8, 2006 Page iii

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

Section Title Page

3.3.4 Annunciator 3-3

3.3.5 MODE Control 3-4

3.3.6 Radio Functions 3-5

3.3.7 Muting Logic 3-5

3.3.8 Automatic Fail-safe 3-6

Feb 8, 2006 Page iv

ENG-FORM: 820-0110.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.

SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

Section 1 Description

1.1 Introduction

This manual contains information on the AA83-001 InterMUSIC™ Stereo Intercom
System serial numbers 2939 and later. All derivative products 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 AA83-001 is a 4-place stereo voice-activated intercom, providing full intercom
capabilities for pilot, copilot and two passengers (PAX). The AA83-001 has a built-in
tieline with tie/split capability, providing support for additional users in a multi-unit
system.

The AA83-001 also provides transmit capability for pilot and co-pilot to a single COM
radio or audio selector panel. The AA83-001 accepts stereo music inputs from either
portable or fixed entertainment systems to produce high quality stereo headset output.

1.3 Features

1.3.1 Stereo & Intercom Special Features

The stereo music audio is muted during transmit or intercom operation and when radio
receive audio is detected, permitting greater intelligibility of incoming transmissions.

The AA83-001 muting depth adjustment ranges from complete music muting to gentle
background music on command, with a fast attack and slow level return for optimum
user comfort.

Each microphone is individually gated, for the best possible noise performance during
VOX operation. A front panel annunciator allows easy visual setting of the VOX
threshold, and also indicates transmit operation.

1.3.2 Communication Functions

The AA83-001 provides full boom-mic transmit and ICS functions for the pilot and co­pilot, and provides ICS and radio monitor operation for two additional passengers. Pilot
priority on transmit and pilot isolation/fail-safe (direct connection to the aircraft radio
system) are standard features on all NAT intercom systems. The AA83-001 can
support PTT ICS operation for all users, and can be wired to cyclic/yoke switches for
both TX and ICS functions.

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

1.4 Specifications

1.4.1 Electrical Specifications

Input Power Linear regulator with over voltage protection

Operating Voltages:
Nominal 27.5 or 13.8 Vdc @ 550 mA max (one input for both)
Maximum 30.3 Vdc
Minimum 11.0 Vdc

Internal supply 11 Vdc

Input Signals

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

TX Keyline
Quantity 2 (Pilot, Co-pilot).
Rated level ground activates keyline, <20 mA source current

ICS Keyline
Quantity 4 (Pilot, Co-pilot, 2 Passengers).
Rated level ground activates keyline, <1 mA source current

Receive Audio
Quantity 1
Rated level 2.5 Vrms nominal (1.3 to 5.0 Vrms)
Impedance 1.2 kOhm ±20 %
Circuitry type unbalanced

Music Inputs
Quantity 2 (left channel, right channel)
Rated level 1.4 Vrms nominal (850 mVrms to 2.4 Vrms)
Impedance 12.5 kOhm ±10 %
Circuitry type unbalanced

Bidirectional Signals

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

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

Output Signals

Phones
Quantity 4 (Pilot, Co-pilot, 2 Passengers)
Rated level >5.5 Vrms (>100 mW, RX and ICS and music)
Impedance 300 Ohm ±10 %
Circuitry type transformer, unbalanced

Radio TX Mic
Quantity 1
Rated level 250 mVrms ±10 %
Impedance 150 Ohm nominal
Circuitry type direct throughline via relay

Radio TX Keyline
Quantity 1
Rated level <1 A
Circuitry type grounded relay contact

Audio Performance

Per RTCA DO-170 except where noted. Product Classification: 1a

Rated Output Power 100 mW min. into 300 Ω (each stereo channel)
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 -50 dB max*
Input - Output crosstalk -55 dB max.
Input - Mic crosstalk <1.0 mVrms*
Audio noise -50 dB max
Output Regulation ≤3 dB variance (350 to 6000 Hz)
Audio Communication Loud & Clear
ICS Volume control ≥35 dB*, 40 dB nominal
Music Volume control ≥35 dB*, 40 dB nominal
Amplifiers with Compression N/A
Stability and Short Circuit Protection
No spurious or sustained oscillations.
Receive Input impedance 1.2 kΩ ±20%
Mic Input impedance 150 Ω ±10%
Music Input impedance 12.5 kΩ ±10 %
Tie Line 2 kΩ ±10 %

Note: * Denotes manufacturer's specification

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

Miscellaneous Audio Performance

ICS BAL control: ≥20 dB dynamic range
MUS BAL control: ≥20 dB dynamic range
RX BAL control: ≥20 dB dynamic range
ICS BASS control: ±2.5 dB min. range at 350 Hz*
MUS BASS control: ±2.5 dB min. range at 350 Hz*
MUS MUTE control: -60 dB to –10 dB
Music attack/decay time: < 7 seconds
RX volume control: ≥35 dB dynamic range
* measured at –10 dB ref: rated input level.

1.4.2 Physical Specifications

Height 1.32" (33.5 mm) max

Depth 7.20" (182.9 mm) max

5.84" (148.3 mm) max behind panel

Width 2.62" (66.5 mm) max panel width

Weight 0.70 lbs (0.32 kg) max

Mounting Through front panel; three 6-32 black brass

screws. Aircraft panel thickness 0.050" to 0.125"

Faceplate Panel is a rectangular double-sided photo-

imaged 0.062" aluminum plate, 1.32" high x

2.62" wide, max

Material/Finish Chassis and Cover: Brushed aluminum with

chromate conversion

Connectors One 44 pin male high-density D-min connector

with jackposts

Installation Kit AA83-IKC

1.4.3 Environmental Specifications

Temperature -20o to +55o C

Altitude 50,000 ft

Shock 6g/11ms, 20g/11ms, 20g/3s sustained.

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

End of section 1

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System 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 for the AA83-001

InterMUSIC

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:

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

2.2.1 Warranty

™

Stereo Intercom, serial numbers 2939 and later.

- AA83-001 InterMUSIC™ Stereo Intercom

- Installation kit (see section 2.5)

- Warranty Card

- Operator’s Manual

- Release certification

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

High volume settings can cause hearing damage.

Set the headset volume control to the minimum volume

setting prior to conducting audio tests, and slowly increase

the headset volume to a comfortable listening level.

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

2.3.2 Cautions

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

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

All audio installations can be seriously degraded by incorrect wiring and shielding, and
may result in abnormal cross-talk, hum and ground-loop noise. Be especially careful
with all microphone wiring and Tie Line wiring, as these lines carry the lowest level
signals in the aircraft.

All microphone and headset jacks should be electrically isolated from the airframe or
significant ground loop noise may result.

2.3.3 Cabling and Wiring

All unshielded wire shall be selected in accordance with AC43.13-1B Change 1,
Paragraphs 11-76 through 11-78. Wire types should be to MIL-W-22759 as specified
in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11. 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. Aircraft harnessing should permit the unit to be lowered from the
panel for easy access to all side adjustments. Do NOT mount the unit until all
adjustments have been carried out.

All wiring should be at least 22 AWG. Ensure that all ground connections are clean and
well secured, and that they share no path with any electrically noisy aircraft accessories
such as blowers, turn and bank instruments or similar loads. Power to this unit must be
supplied from a separate breaker (1 A) or fuse (1 A fast), and not attached to any other
existing breaker without additional protection. The correct fuse is included with the
AA83.

Ensure that all ground connections are clean and well secured.

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

2.3.4 Adjustments

The unit ships 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.

CAUTION

Before performing the following adjustments ensure the aircraft radio’s
volume control is set to produce 2.5 Vrms ±10 % at the input to the
AA83-001, or the mute functions may not operate correctly.

The internal adjustments are located along the sides of the unit and are as follows:

Left side of unit

Right side of unit

2.3.4.1 ICS, RX, and MUSIC BAL.

These potentiometers are used to adjust the headset stereo balance.

2.3.4.2 ICS and MUSIC BASS

These potentiometers are used to adjust the amount of bass audio to the headsets.
Rotating ccw will lower the bass level, and cw will raise it.

2.3.4.3 RX VOL

To reduce the receive audio volume, rotate this potentiometer ccw, and to increase the
volume, rotate it cw.

2.3.4.4 MUSIC MUTE

The music mute level can be adjusted using this potentiometer.

2.3.5 Mechanical Installation

Before the unit is mounted, make all functional tests and trimpot adjustments. Be sure

the harness has enough clearance to permit the unit to be dropped down for re­adjustment, if needed later. Make sure unit is securely fastened to the panel, and that
the connector locks are tightened before any flight is attempted.

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

The AA83-001 can be installed in a vertical or horizontal
attitude directly on the instrument console, using the AA83­IKC Installation kit (see Section 2.5 for details).

For proper installation, refer to Mounting Diagram (AA83\001\920-0) and Drill

Template (AA83\001\921-0) and the following steps:

Note: The mounting nuts on the panel pots should not be removed at any time.

a) After deciding the attitude (vertical or horizontal) of the unit, drill the required

mounting holes in the aircraft panel and insert the AA83-001 from behind the panel.

b) Remove the protective plastic film from the black metal faceplate, and position it

with the appropriate legend orientation facing out. Secure with the mounting
screws provided.

Note: Ensure that the aircraft panel is tightly ‘sandwiched’ between the AA83-

001 and faceplate.

c) Rotate the inner and outer shafts of the ICS VOL / VOX potentiometer fully ccw.

The outer knob may be rotated by hand, but it may be necessary to temporarily
attach the inner ICS knob to facilitate this action. Align the white markers on the
knobs (part of 40-21-ICS3) to the LIVE position on the faceplate label. Using a

0.05" Allen key, tighten the knobs onto the potentiometer shafts.

d) Rotate the shaft of the MUSIC VOL potentiometer fully ccw. Align the white

marker on the knob (part of 40-21-MUS3) to the LIVE position on the faceplate
label. Using a 0.05" Allen key, tighten the knob onto the potentiometer shaft.

Note: Make sure there is enough clearance between the concentric knobs so

that rotating one does not also move the other. A piece of paper makes a
good spacer when setting up the clearance.

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

2.3.6 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.

2.3.6.1 Voltage/resistance checks

Do not attach the AA83-001 until the following conditions are met.

Check the following:

a) Check P101, pin <1> for avionics buss voltage relative to ground.

b) Check P101, pin <16> for continuity to ground (less than 0.5 Ω).

c) Check P101, pins <9> <10> <11> and <12> (and <13> and <14> if applicable)

for continuity to ground (less than 0.5 Ω) when the relevant switch is keyed.

d) Check all mic, phone, music, and key lines for shorts to ground or adjacent pins.

Check all key lines for correct operation.

2.3.6.2 Power On checks

WARNING

High volume settings can cause hearing damage.

Set the headset volume control to the minimum volume

setting prior to conducting audio tests, and slowly increase

the headset volume to a comfortable listening level.

Install the AA83-001 and power up the aircraft’s systems, and turn on the radios and
accessories required. Verify normal operation of all functions. Refer to Section 3 for
specific operation details.

a) Begin with only the pilot's headset installed; no hand mic. Check for correct radio

operation (both receive and transmit) and ICS operation. Check yoke (or cyclic)
switch action.

b) If there is a music source in the system turn it on and verify that music is heard in

all modes except PLT ISO. Check for proper mute operation.

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

Note: Unusual buzzes, hums or other background audio may be symptomatic of

multiple grounds or noisy external systems sharing the same wire bundle.
Incorrect jack wiring is a common fault, especially for passenger stations, and
may cause loss of audio, a tone on the headset lines, or other problems.

c) Plug in the copilot's headset. Check for correct radio and ICS operation. Check

pilot's transmit priority. Check yoke or cyclic switch functions, if applicable.

d) Plug in the hand mic (if applicable to the installation), and test for correct

operation in all modes. It must activate the transmitter(s) in all cases.

e) Plug in any remaining headsets, and check for correct ICS operation.

f) To verify proper operation, all functions and levels should be checked in-flight.

g) To verify 'fail-safe' operation, ensure that the front-panel switch is in the NORM

position, and then pull the breaker or fuse that powers the AA83-001. The pilot's
headset is now connected directly to the COM or audio panel, and should be
checked to ensure the RX and TX functions work properly. It may be necessary
to adjust the RX VOL side trimpot to ensure RX audio from the audio panel is at
a suitable level for audibility.

Be sure headsets are of good quality and are installed correctly. Unless the AA83 has
specifically been wired for mono operation NEVER USE MONO AIRCRAFT
HEADSETS in the system, as they will short out one side of the AA83 power amplifier
when installed in stereo jacks. This may result in eventual unit failure, which IS NOT
COVERED BY WARRANTY.

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 AA83-001 is ‘on condition’ only. Periodic maintenance of this
product is not required.

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

2.5 Accessories Supplied

Installation kit p/n AA83-IKC is required to complete the installation. The kit consists of
the following:

Quantity Description NAT Part #

1 D-sub Socket 20-20-044
44 Contacts 20-26-703
1 Jackscrew, D-sub, Pair 20-27-002
1 Hood, D-sub, Plastic 20-29-026
1 AGC, Fast, 1 A 23-00-006
3 Screw, panhead, Phillips, Brass, Black 25-11-427
1 Knob, Fluted Concentric, Rubber 40-21-ICS3
1 Knob, Fluted Concentric, Rubber 40-21-MUS3
1 Legend and Template, AA83 43-10-083
1 Faceplate, Rectangular, AA83-001 50-04-831

2.6 Installation Drawings

DRAWING REV. DESCRIPTION TYPE SERIAL #

AA83\001\302-0 1.00 Stereo Intercom Block Diagram 2939 and up

AA83\001\403-0 2.00 Stereo Intercom Interconnect 2939 and up

AA83\001\405-0 2.00 Stereo Intercom Connector Map 2939 and up

AA83\001\905-0 2.00 Stereo Intercom Faceplate 2939 and up

AA83\001\920-0 2.00 Stereo Intercom Mounting Diagram 2939 and up

AA83\001\921-0 1.00 Drill Template Drill Template 2939 and up

AA83\001\922-0 2.00 Stereo Intercom Mech. Installation 2939 and up

Section 2 ends after these Drawings

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Confidential and Proprietary to NAT

Confidential and Proprietary to NAT

SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

Section 3 Operation

3.1 Introduction

Information in this manual consists of the functional and operational procedures for the
AA83-001 InterMUSIC

™

Stereo Intercom, serial numbers 2939 and later.

3.2 General Operation

The AA83-001 is a 4-place stereo voice-activated intercom, providing full intercom
capabilities for pilot, copilot and two passengers (PAX). The AA83-001 has a built-in
tieline with tie/split capability, providing support for additional users in a multi-unit
system.

The AA83-001 also provides transmit capability for pilot and co-pilot to a single COM
radio or audio selector panel. The AA83-001 accepts stereo music inputs from either
portable or fixed entertainment systems to produce high quality stereo headset output.

The InterMUSIC

™

family of stereo intercoms allows several installation configurations ­from single unit systems, to fully independent stations for the pilot, copilot and
passengers. For expanded systems, tie line connections are compatible with other NAT
systems including AA82, AMS4x and AA9x series units.

3.2.1 Stereo & Intercom Special Features

The stereo music audio is muted during transmit or intercom operation and when radio
receive audio is detected, permitting greater intelligibility of incoming transmissions.
The AA83-001 muting depth adjustment ranges from complete music muting to gentle
background music on command, with a fast attack and slow level return for optimum
user comfort. Each microphone is individually gated, for the best possible noise
performance during VOX operation. A front panel annunciator allows easy visual
setting of the VOX threshold, and also indicates transmit operation.

3.2.2 Communication Functions

The AA83-001 provides full boom-mic transmit and ICS functions for the pilot and
copilot, and provides ICS and radio monitor operation for two additional passengers.
Pilot priority on transmit and pilot isolation/fail-safe (direct connection to the aircraft
radio system) are standard features on all NAT intercom systems. The AA83-001 can
support PTT ICS operation for all users, and can be wired to cyclic/yoke switches for
both TX and ICS functions.

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A

f

t

p

3.2.3 Important Operating Considerations

Ensure headsets are of good quality and are installed correctly. NEVER USE MONO
AIRCRAFT HEADSETS in this system unless the installation has been specifically

wired for mono operation, as they will short out one side of the AA83-001 power
amplifier when installed in stereo jacks. This may result in eventual unit failure, which
IS NOT COVERED BY WARRANTY. Use only stereo headsets with this system, and
be sure the aircraft is placarded appropriately.

3.2.4 Installation Adjustments

Using individual level trimpots, an approved dealer can adjust the following audio levels
during service, or at the time of installation.

•

Music mute level

• • •

Music Bass level RX volume level ICS Bass level

•

Music balance

•

RX Balance

•

ICS Balance

3.3 Controls and Indicators

Dual Control:
ICS Volume (inner)
Pilot VOX (outer)

Dual Control:
Music Volume (inner)
Copilot VOX (outer)

MODE Switch

nnunciator

3.3.1 ICS VOL/PILOT VOX

This control is a fluted concentric rubber knob on the left side o
the front panel.

The inner (front) knob is the ICS VOL control, which is used to se
Intercom volume. It is at minimum volume when fully counter-
clockwise (ccw). As the knob is rotated clockwise(cw), the ICS
volume for crew and PAX increases. The ICS is muted during
transmit o

erations.

The outer (rear) knob is the PILOT VOX control, that controls VOX for the pilot only.
For full information on VOX operation, see section 3.3.3 below.

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3.3.2 MUSIC VOL/COPILOT VOX

This control is a fluted concentric rubber knob on the right
side of the front panel.

The inner (front) knob is the MUSIC VOL control, which is
used to set normal music volume. The volume can be
adjusted from minimum (fully ccw) to maximum (fully cw).

The outer (rear) knob is the COPILOT VOX control, that controls VOX for the copilot
and passengers. For full information on VOX operation, see section 3.3.3 below.

3.3.3 VOX Operation

The VOX control is used to set the level of audio required to activate the microphones.
The AA83-001 provides three modes of intercom operation, selected by the position of
the VOX control.

LIVE ICS When the VOX control is positioned fully ccw to the LIVE position, all mics

will be live, and any sound picked up will be processed by the ICS system
(hot mic).

KEYED ICS When the VOX control is positioned fully cw to the MAX position, 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.

3.3.4 Annunciator

The front panel annunciator is a bi-colour LED that shows intercom status.

If the LED is illuminated green, it indicates transmit activity, and if it is red, it indicates
VOX activity. For transmit with sidetone or mic activity, it will illuminate amber. The
green LED also indicates a possible stuck mic if still lit after transmission is concluded.

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

3.3.5 MODE Control

MODE Switch

The mode control is a three-position toggle switch used to select the operational mode
of the unit. The selectable positions are SPLIT, PIL ISO and NORMAL. These modes
are described fully in sections 3.3.5.1, 3.3.5.2 and 3.3.5.3 below.

3.3.5.1 NORMAL Operation

In normal use, the AA83-001 serves as a common intercommunication system for up to four
users, and a flow-through interface for connection to the ship's external communication
system. The NORM mode (default) permits everyone on the system to talk to each
other, listen to music, and hear all radio communications.

Radio transmit functions may be initiated by either the pilot or the copilot. The pilot has
priority.

In NORM mode, external tie line users are included in the ICS communications.

3.3.5.2 PIL ISO (Pilot Isolation) Operation

In normal operation, the pilot, copilot, and passengers hear the same signals from the
aircraft communication system. Sometimes this is not desirable from the pilot's
perspective, for instance during communication with the tower on approach, or when
discussions on the intercom would be a distraction. Many times the copilot position is
simply another passenger, and the pilot may wish to be isolated from them.

PILOT ISO mode separates the pilot from the intercom network, allowing confidential
radio communications without interference from the copilot or passenger intercom or
music. The pilot has no ICS operation, and all signals are presented in mono format
during this mode. All other users are unaffected and continue to use the
entertainment and intercom functions of the AA83-001.

While in PILOT ISO mode, the pilot maintains complete control of all the radio
functions of the intercom, and the pilot mic and TX keyline are directly connected to
the transceiver. The pilot phones are driven by the transceiver.

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SM09-2A Rev. 4.00 AA83-001 InterMUSIC™ Stereo Intercom System Manual

The copilot and passengers will be unable to monitor any transceiver activity, although
they retain full ICS and music functions.

This mode is 'fail-passive', meaning that it requires no power to operate and is the
same mode the box goes into automatically when power is lost to the AA83-001.
In this way, switch over is immediate for the pilot and there is no possibility of lost
communication because of a lack of pilot action. Note that the pilot's boom mic is sent
directly to the radio in this mode, and only a PTT key input is needed to transmit.

Note: In this mode, the receive/sidetone levels may require adjustment at the audio

source.

3.3.5.3 SPLIT Operation

Operation in SPLIT Mode is similar to NORM mode, but if the AA83-001 is connected
as part of a multi-unit system, the SPLIT mode allows external users to be disconnected
from the AA83-001 ICS communications without requiring adjustment of the ICS Audio
level.

All users are permitted to talk to each other, listen to music, and hear all radio
communications.

There is provision for an external ICS tie line load to maintain the ICS audio at the same
level as in NORM mode.

3.3.6 Radio Functions

There are two PTT inputs: one each for the pilot and copilot. Activation of either PTT
input connects the user’s MIC to the radio, and activates the output PTT to the radio.

Sidetone audio input is provided from the radio, not by the AA83-001 microphone
circuits. Transmit sidetone audio utilizes AA83-001 Radio RX audio and phones driver
circuits.

Radio RX/sidetone is a mono signal, but RX balance control may be adjusted to provide
spatial displacement to aid user in quick signal identification.

Note: A priority transmission feature allows the pilot to override the copilot.

3.3.7 Muting Logic

When transmitting, any music will be muted quickly, and will slowly return when
transmission is completed. Music will also be muted when ICS or RX functions are
active. The degree of muting is set at the time of installation. The relative volume of
the music can be changed from the front panel by the knob marked with a musical
note.

Feb 8, 2006 Page 3-5

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AA83-001 InterMUSIC™ Stereo Intercom System Manual SM09-2A Rev. 4.00

Below is a simple chart to aid in understanding audio switching in the NORMAL
Operation mode.

The following terms are used:

'Active' - Function being used.
'Muted' - Functions that are overridden by the active condition.
'Idle' - Functions that are not active, but still available for use.

Active feature→

Music→

ICS→

RX→

Pilot TX→

Copilot TX→

Music ICS RX Pilot TX Copilot TX
Active
Muted
Muted Idle
Muted Muted Idle
Muted Muted Idle Idle

↓ Affect on other functions ↓

Idle Idle Idle Idle
Active

Idle Idle Idle
Active

Idle Idle
Active

Muted
Active

3.3.8 Automatic Fail-safe

In the event of a power failure, automatic fail-safe operation will be activated. It can also
be enabled by pulling the AA83-001 circuit breaker. Fail-safe mode routes the pilot’s
phones, mic audio, and mic PTT directly to the COM radio.

During transmit mode, the pilot mic is directly connected to the transceiver mic. Mic
bias is provided by the transceiver, not the AA83-001. The pilot TX keyline is directly
connected to the transceiver. The sidetone audio is directly connected from the audio
source to the pilot phones.

During receive mode, receive audio is directly connected from the audio source to the
pilot phones.

In both modes, copilot and passengers have no ICS, music, sidetone, or receive
functions.

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

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