Northern Airborne Technology AA38-5xx User Manual

Installation and Operation Manual

AA38-5xx, -6xx, -7xx and -8xx Series

Local ICS Loop

SM54

ISSUE 4.11

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

Telephone [phone]

Facsimile [phone]

Issued on the authority of Northern Airborne Technology Ltd.

Copyright 2008

V1Y 4N7

AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop

SM54 Installation and Operation Manual

Prepared By: Checked By: Approved By:

The status of this installation and operation manual is controlled by issue shown on the title page. The
status of each section is controlled by revision shown in the footer of each page. All revisions affecting
sections of this manual have been incorporated into the latest issue.

ISSUE/REVISION RECORD

Manual Issue

Number

Section

Revision Number

Revision Description Issue Date

4.11 Section 1 Rev: 1.01 Remove reference to Environmental
Qualification Form.

4.10 Section 1 Rev: 1.00

Section 2 Rev: 1.00
Section 3 Rev: 1.00

Update to current templates. Jun 9, 2008

Jan 13, 2010

Installation and Operation Manual Page ii

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AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop

SM54 Installation and Operation Manual

Table of Contents

Section Title Page

1. Description

1.1 Introduction 1-1

1.2 Product Description 1-1

1.3 Design Features 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

1.5 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 Continued Airworthiness 2-1

2.4 Installation Procedures 2-2

2.4.1 Cabling and Wiring 2-2

2.4.2 Post Installation Checks 2-2

2.5 Adjustments and Connections 2-3

2.5.1 Headset Volume and Sensitivity Adjustments 2-4

2.5.2 Auxiliary Receive control(s) 2-4

2.5.3 Mode Control (AA38-5xx and -6xx) 2-4

2.5.4 Mode control (AA38-7xx and AA38-8xx) 2-5

2.5.5 Remote ICS Master Volume Control (AA38-7xx and AA38-802) 2-7

2.6 Accessories Required But Not Supplied 2-7

2.7 Installation Drawings 2-7

3. Operation

3.1 Introduction 3-1

3.2 General Information 3-1

3.3 Controls and Indicators 3-1

3.3.1 AA38-5xx and AA38-6xx 3-1

3.3.2 Master ICS Volume Control (AA38-7xx and AA38-8xx) 3-1

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AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop Manual

SM54 Installation and Operation Manual

Section 1 Description

1.1 Introduction

Information in this section consists of product description, design features and specifications for the
AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop Manual. All derivative product information shall be
contained in the applicable manual supplement, which may be obtained from Northern Airborne
Technology Ltd as required.

Review all notes, warnings and cautions.

1.2 Product Description

The AA38-5xx Series Local ICS Loops (not AA38-505) provide live, VOX or keyed ICS for 4 or 8 users
(depending on model) with low impedance headsets.

The AA38-6xx Series Local ICS Loops provide live, VOX or keyed ICS for 4 or 8 users (depending on
model) with high impedance headsets.

The AA38-7xx Series Local ICS Loops provide an external ICS Volume control, and live, VOX or keyed
ICS for 4 users with low impedance headsets.

The AA38-8xx Series Local ICS Loops provide an external ICS Volume control, and live, VOX or keyed
ICS for 8 users with high impedance headsets.

The AA38-503, AA38-603 and AA38-703 models have prioritized transmit capabilities for all users, with
the highest priority given to user #1 and lowest to user #4.

The AA38-505 Series Local ICS Loops provide live, VOX or keyed ICS for 4 users with high impedance
headsets.

1.3 Design Features

The AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loops are remote, bulkhead mounted units
containing all the circuitry required to support a wide variety of ICS Loop applications, particularly
isolation/ICS amplifier use, where the output is required to be headset or line level. A switch-selectable
NAT/Andrea (AA38-5xx or -6xx) or NAT/SuperNAT ICS tie line (AA38-7xx or AA38-8xx) allows
connection to larger audio systems, and an auxiliary input allows for audio input from an audio panel or
transceiver.

The compact size and low weight of the AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loops allows
mounting in restricted locations, and the mapped interconnect makes installation simple to carry out.

ICS level and VOX sensitivity adjustments are provided for each headset position and for the AUX level.
The operational performance of the AA38 unit can be enhanced for specific operating roles with the

addition of in-line PTT drop cords. Drop cords can be configured to allow individual selection of headset
volume, intercom operation in VOX, LIVE or PTT mode, and independent TX PTT capability for those
AA38 models equipped with TX functions.

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SM54 Installation and Operation Manual

1.4 Specifications

1.4.1 Electrical Specifications

Power Supply

Input Signals

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Type DC Linear
Input Voltage Typically +24.8 to +30.3 Vdc

Nominal +27.5 Vdc (with reverse & over voltage protection)
Emergency +20.0 Vdc

Input Current 0.45 A Max. @ +27.5 Vdc (AA38-501, -503, -504, -505)

0.80 A Max. @ +27.5 Vdc (AA38-502, -602)

0.41 A Max. @ +27.5 Vdc (AA38-601, -603)

0.35 A Max. @ +27.5 Vdc (AA38-703)

0.90 A Max. @ +27.5 Vdc (AA38-802)

Quantity 8 MIC channels
(AA38-502, -602 and -802) 2 ICS tie channels, one for each group of 4 users
2 AUX RX channels, each driving 4 users

Quantity 4 MIC channels
(except AA38-502, 1 ICS tie channel

-602 or -802) 1 AUX RX channel
Audio Level 250 µVrms for MIC inputs (AA38-5xx except -505, -7xx models)

1.1 mVrms for MIC inputs (AA38-505 model only)
250 mVrms for MIC inputs (AA38-6xx models only)
340 mVrms for NAT ICS tie input(s)

2.8 Vrms for Andrea ICS tie input(s) (AA38-5xx and -6xx models)

2.5 Vrms for AUX RX input

1.2 Vrms (typical) for SuperNAT ICS (AA38-7xx and -8xx)
Circuitry Type Tie lines are single ended inputs

All AA38-5xx model MICs are differential inputs
All AA38-6xx model MICs are single ended inputs
All AA38-7xx model MICs are differential inputs
All AA38-8xx model MICs are balanced inputs
All AUX RX inputs are balanced

Keylines 4 ICS PTT active low (AA38-501, -504, -505, -60 1)
8 ICS PTT active low (AA38-502, -602, -802)
4 ICS PTT active low (AA38-503, -603, -703)
4 TX PTT active low

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Output Signals

Quantity 4 Headphone outputs (AA38-501, -503, -504, -505, -601, -603, -703)
8 Headphone outputs (AA38-502, -602, -802)

Rated Level Selectable between 8 and 600 Ω (except AA38-703 or -802)

7.7 Vrms or 100 mW (20 dBm) into 600 Ω (except AA38-703)

0.9 Vrms or 100 mW (20 dBm) into 8 Ω (except AA38-802)
ICS Tie Output level selectable between 1.6 kΩ (NAT ICS tie) and 250 Ω

(except AA38-504, (Andrea ICS tie)
AA38-703 and AA38-802) 140 mVrms ±10% for NAT ICS tie output (4 NAT loads)

2.8 Vrms ±10% for Andrea ICS tie output
ICS Tie Output level selectable between 1.6 kΩ (NAT ICS tie) and 250 Ω

(AA38-504 only) (Andrea ICS tie)
300 mVrms ±10% for NAT ICS tie output (1 NAT load)

3.8 Vrms ±10% for Andrea ICS tie output
ICS Tie 340 ±50 mVrms for NAT ICS tie output (1 NAT load)

(AA38-703 only) 1.2 ±0.1 Vrms for SuperNAT ICS tie output (1 to 4 SuperNAT

ICS Tie 340 ±50 mVrms for NAT ICS tie output (2 NAT loads)
(AA38-802 only) 1.2 ±0.1 Vrms for SuperNAT ICS tie output (1 to 8 SuperNAT

Impedance / Output 1-4 x 600 Ω or 1-4 x 8 Ω
1-8 x 600 Ω or 1-8 x 8 Ω (AA38-502 and -602 only)
2 ±0.2 kΩ for NAT ICS tie line
2 ±0.2 kΩ for SuperNAT ICS tie line (AA38-703 and -802 only)

Phones Circuitry Type Balanced output for high common mode noise rejection
ICS Tie Line Circuitry Type Single ended
Frequency Response ICS: ≤3 dB from 350 to 3000 Hz

MIC Input: ≤3 dB from 350 to 3000 Hz
AUX RX Input: ≤3 dB from 350 to 6000 Hz

Distortion ≤10% THD @ rated power output
Audio Noise Level ≤-60 dB from rated output (without signal)
Coupling ≤-50 dB input to output crosstalk
Output Regulation at 400% ≤10% distortion / Δ 3dB max rated output power for 600 Ω output

and 75% of rated load ≤10% distortion / Δ 7dB max rated output power for 8 Ω output

AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop Manual

SM54 Installation and Operation Manual

loads)

loads)

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SM54 Installation and Operation Manual

1.4.2 Physical Specifications

AA38-501,

-504, -505

AA38-502 AA38-503 AA38-601 AA38-602 AA 38-603 AA38-703 AA38-802

Height

Max.
Depth 4.88" (124.0 m m) max. including connecto r 4.95" (125.7 mm)
Width 5.91" (150.1 mm) max. including flanges 5.94" (150.9 mm)

Weight

Max.

Mounting Bulkhead mount with four 10-32 screws

Material/

Finish

Connectors

1.18"

(30.0 mm)

1.14 lbs

(0.52 Kg)

2.26”

(57.4 mm)

2.00 lbs

(0.91 Kg)

Filtered male 37-pin D-subminiature connector with Positronics V5 locking tabs.

1.90"

(48.3 mm)

1.40 lbs

(0.63 Kg)

5052-H32 brushed aluminum with chromate conversion finish

(Two in the AA38-502, -503, -602, -603, -703 and -802)

1.18"

(30.0 mm)

0.80 lbs

(0.36 Kg)

2.26”

(57.4 mm)

1.37 lbs
(0.6 Kg)

1.90"

(48.3 mm)

1.20 lbs

(0.54 Kg)

1.60 lbs
(0.7 Kg)

1.94"

(49.3 mm)

1.4.3 Environmental Specifications

Temperature -45 to +55°C (ambient)

-55 to +85°C (survival)
Altitude 35,000 feet max.
Humidity 95% for 48 hours
Vibration/Shock Conforms to DO-160C category B, M, N

Qualification of the AA38-5xx Local ICS Loop was completed in accordance with
DO-160C Env. Cat. A1C4-BA[BMN]XXXXXXABABBTBXXX.

Qualification of the AA38-6xx Local ICS Loop was completed in accordance with
DO-160C Env. Cat. A1C4-BA[BMN]XXXXXXABABBTBXXX.

Qualification of the AA38-703 Local ICS Loop was completed in accordance with
DO-160C Env. Cat. A1C4-BA[BMN]XXXXXXZBABXXB

DO-160D Env. Cat. XX-XXXXXXXXXXXXXXXS

1

RF Susceptibility testing was performed to DO-160D, change 1, Sec. 20, Cat. S.

1

1

XXXXX.

XXX.

Note: The AA38-802 has not been tested for compliance to any DO-160 categories at this time.

1.44 lbs

(0.69 Kg)

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SM54 Installation and Operation Manual

1.5 Unit Nomenclature

AA38-501 LO Z Local ICS Loop - Four Place Intercom

4 MIC inputs - 0.250 mV / 5 Ω
1 ICS Tie line - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 kΩ
4 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

AA38-502 LO Z Local ICS Loop - Eight Place Intercom

8 MIC inputs - 0.250 mV / 5 Ω
2 ICS Tie lines - 1.6 kΩ (NAT) or 250 Ω (Andrea)
2 AUX inputs - 1 kΩ
8 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

AA38-503 LO Z Local ICS Loop - Four Place Intercom with Transmit

4 MIC inputs - 0.250 mV / 5 Ω
1 ICS Tie line - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 kΩ
4 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation
Individual TX PTT for each user (ascending priority)

AA38-504 LO Z Local ICS Loop - Four Place Intercom, High Gain Microphones

4 MIC inputs - 0.250 mV at 5 Ω
1 ICS Tie line input - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 kΩ
4 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

AA38-505 Hi Z Local ICS Loop - Four Place Intercom

4 MIC inputs – 1.1 mV / 150 Ω
1 ICS Tie line - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 kΩ
4 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

AA38-601 Hi Z Local ICS Loop - Four Place Intercom

4 MIC inputs - 250 mV / 150 Ω
1 ICS Tie line - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 k Ω
4 headset outputs 100 mW @ 8 or 600
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

Section 1 Rev: 1.01 Issue 4 Page 1-5

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Ω

AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop Manual

SM54 Installation and Operation Manual

AA38-602 Hi Z Local ICS Loop - Eight Place Intercom

8 MIC inputs - 250 mV / 150 Ω
2 ICS Tie lines - 1.6 kΩ (NAT) or 250 Ω (Andrea)
2 AUX inputs - 1 kΩ
8 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation

AA38-603 Hi Z Local ICS Loop - Four Place Intercom with Transmit

4 MIC inputs - 250 mV / 150 Ω
1 ICS Tie line - 1.6 kΩ (NAT) or 250 Ω (Andrea)
1 AUX input - 1 k Ω
4 headset outputs 100 mW @ 8 or 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation
Individual TX PTT for each user (ascending priority)

AA38-703 LO Z Local ICS Loop - Four Place Intercom with Transmit, External ICS Volume

4 MIC inputs - 0.250 mV / 5 Ω
1 ICS Tie line - 2 ±0.2 kΩ for NAT and SuperNAT
1 AUX input - 1 kΩ
4 headset outputs 100 mW @ 8 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation
Individual TX PTT for each user (ascending priority)
External ICS Volume Control

AA38-802 Hi-Z Eight Place Intercom - with Master Volume

8 MIC inputs - 250 mV / 150 Ω
2 ICS Tie line - 2 ±0.2 kΩ for NAT and SuperNAT
2 RX inputs - 1 kΩ
8 headset outputs 100 mW @ 600 Ω
Balanced output for high common mode noise rejection
LIVE, VOX or PTT operation
External ICS Volume Control

Section 1 ends

Section 1 Rev: 1.01 Issue 4 Page 1-6

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Section 2 Installation

2.1 Introduction

Information in this section consists of unpacking and inspection procedures, installation procedure s, po st­installation checks and installation drawings for the AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop.

Review all notes, warnings and cautions.

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. Check that all items listed below
are present before proceeding and report any shortage immediately to your supplier:

- Warranty Card

- Certificate of Conformity or Release Certification

2.2.1 Warranty

All Northern Airborne Technology Ltd. products are warranted for 2 years from date of installation by an
authorized NAT dealer, to be free of defects in workmanship or performance. This warranty covers all
materials and labour, but is exclusive of any transport to deliver the defective unit to and from NAT or its
designated warranty repair center, or any labour to remove or re-install the defective unit in the aircraft.
Contact NAT for any questions regarding this warranty, its applicability to your units and/or for return
authorization. NAT is the final arbitrator concerning warranty administration. Units which have been
physically damaged, burned, immersed in water or otherwise abused beyond the scope of normal use will
not be considered for warranty. WARRANTY IS VOID UNLESS THE PRODUCT IS INSTALLED BY AN
AUTHORIZED NAT DEALER. Product for which a warranty card is not returned shall be warranted from
date of manufacture.

2.3 Continued Airworthiness

Maintenance of the AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop is ‘on condition’ only. Periodic
maintenance of this product is not required.

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2.4 Installation Procedures

2.4.1 Cabling and Wiring

All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify 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 solde r sleeve s (fo r shield
terminations) to make the most compact and easily terminated interconnect. Follow the connector map in
Section 2.6 as required.

Coaxial cable shall be selected in accordance with MIL-C-17 unless otherwise specified. Do not use coax
cable with PVC insulation. Teflon dielectric cable is encouraged at or above VHF frequencies or where
cable runs exceed 8 feet. Note that at VHF frequencies, cables losses due to long cable runs and tight
bends may reduce the ERP (Effective Radiated Power) by greater than 50%.

Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Reference the interconnect drawing in Section 2.6 for shield termination details. Note that
the hood is a "clamshell" hood, and is installed after the wiring is complete. Aircraft harnessing shall
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 performed.

Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions. Coaxial cables shall be routed separately from existing wire bundle s in the
aircraft to minimize electromagnetic coupling effects.

Unless otherwise noted, all wiring shall be a minimum of 24 AWG, except power and ground lines, which
shall be a minimum of 22 AWG. Reference the Interconnect drawing for additional specifications. Check
that the ground connection is clean and well secured, and that it shares 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 circuit breaker or fuse (fast blow), and not attached to any other circuit
breaker without additional protection. Verify that the selected circuit breaker size and wire gauge are
adequate for the installation using the techniques specified in AC43.13-1B Change 1, Paragraphs 11-47
through 11-51 and 11-66 through 11-69.

2.4.2 Post Installation Checks

2.4.2.1 Voltage/Resistance Checks
Do not attach the AA38-5xx, -6xx, -7xx and -8xx Series Local ICS Loop until the following

conditions are met.

Check the following:

a) Check P101, pin 1 for +28 Vdc relative to ground.
b) Check P101, pin 20 for continuity to ground (less than 0.5 Ω).
c) Check P101 pins 3, 5, 7 and 9 for continuity to ground (less than 0.5 Ω) when relevant ICS

PTT line is keyed.

For AA38-502, AA38-602 and AA38-802, repeat this process for the same pins in P102.

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For AA38-503, AA38-603 and AA38-703, also check the following:
d) P102 pin 1 for +28 Vdc relative to ground.
e) P102 pin 20 for continuity to ground.
f) P102 pins 14, 15, 16 and 17 for continuity to ground when relevant TX PTT line is keyed.

For AA38-703, also check the following:
g) P102 pins 11 and 13 for continuity to ground when relevant ICS VOL switch is activated.

For AA38-802, also check the following:
h) P101 and P102 pins 11 and 13 for continuity to ground when relevant ICS VOL switch is

activated.

2.4.2.2 Power On Checks

Power up the aircraft’s systems and confirm normal operation of all functions of the AA38-5xx, -6xx, -7xx
and -8xx. Refer to Section 3 (Operation) for specific operational details.

a) Check for correct radio and intercom audio and adjust for acceptable level.
b) Run through all installed functions, and check the ICS and TX functions for all users.
c) Check preset adjustments are completed before aircraft departure.

Notes: 1. Significantly different headsets may have different MIC characteristics.

2. The David Clark M 7 MIC is more active than the M 4 or M 1/DC MICs. Mixing
different MICs may aggravate headset imbalance.

Upon satisfactory completion of all performance checks, make all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.

2.5 Adjustments and Connections

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. See Section 2.4 for the specific unit under consideration.

The AA38-5xx/6xx/7xx/8xx can be set for up to four NAT tie line configurations, one Andrea tie line
(AA38-5xx and -6xx) or up to four SuperNAT tie lines (AA38-7xx and AA38-802).

The internal adjustments that can be varied are located along the sides and at the rear of the unit. Refer
to Mechanical Installation drawings AA38/xxx/922-0 in Section 2.6 of this manual, where xxx is the model
number under consideration, ie. AA38/503/922-0.

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SM54 Installation and Operation Manual

2.5.1 Headset Volume and Sensitivity Adjustments

The headset volume and sensitivity controls are located on the rear of the unit as shown in Figure 1
below. Each headset position has a level trimpot (L) and a sensitivity trimpot (S) that controls MIC/VOX
operation.

Headset #3 Level (Volume) Adjustment Headset #3 Sensitivity Adjustment

Figure 1: Headset Volume and Sensitivity Controls

The AA38-502, AA38-602 and AA38-802 have two banks of controls. The individual headset level
(volume) controls provide up to 40 dB of dynamic range. For maximum headset power rotate the pot fully
clockwise (cw) and for minimum headset power rotate fully counter-clockwise (ccw).

The individual sense control trimpots are used to select the required operating mode for the headset s. For
KEYED ICS (PTT operation) the trimpot is set fully cw. For LIVE (Hot MIC operation) the trimpot is set
fully ccw. For VOX (Voice Activated operation) the trimpot is set in the mid position.

To obtain the best setting for the ambient noise conditions and the quality and number of MICs connected
in the system, set the trimpot fully ccw, then slowly rotate it cw until the intercom just becomes ‘quiet’.
Check this setting for both ground and flight operation.

2.5.2 Auxiliary Receive control(s)

The Auxiliary (AUX) receive (RX) level trimpot (RX LEVEL) is located on the front of the unit, and provides
up to 40 dB of dynamic range. When rotated fully cw it gives maximum AUX RX input level, and fully ccw
gives minimum level. The AA38-502, AA38-602 and AA38-802 have two of these controls.

2.5.3 Mode Control (AA38-5xx and -6xx)

The Mode Control switch is used for selecting the type of ICS tie line configuration required and is a quad
piano DIP-switch accessible through the left side of the unit. To open a switch, place it in the ‘up’ position
and to close it put it in the ‘down’ position as shown in Figure 2.

Switches 1, 2 and 3 shown in the
closed (down) position.

Switch 4 shown in the open
(up) position.

Figure 2: Mode Control DIP Switch

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