Northern Airborne Technology AMU50-001 User Manual
Installation and Operation Manual
AMU50-001
Audio Management Unit
SM76
ISSUE 1.04
Northern Airborne Technology Ltd.
1925 Kirschner Road
Kelowna, BC, Canada.
Telephone (250) 763-2232
Facsimile (250) 762-3374
Issued on the authority of Northern Airborne Technology Ltd.
Copyright 2009
V1Y 4N7
AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Table of Contents
Section Title Page
1. Description
1.1 Introduction 1-1
1.2 Product Description 1-1
1.2.1 System Information 1-1
1.2.2 System Configuration 1-1
1.3 Design Features 1-2
1.4 Specifications 1-3
1.4.1 Electrical Specifications 1-3
1.4.2 Physical Specifications 1-8
1.4.3 Environmental Specifications 1-8
1.4.4 Product Approval 1-8
1.4.5 DACS System Equipment 1-9
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 2-1
2.4.1 Warnings 2-1
2.4.2 Cautions 2-2
2.4.3 Mounting 2-3
2.4.4 Cabling and Wiring 2-3
2.4.5 Post Installation Checks 2-9
2.5 Adjustments and Configuration 2-10
2.5.1 Maintenance Mode 2-10
2.5.2 DevCs Configurable Settings 2-11
2.6 Accessories Required But Not Supplied 2-12
2.7 Installation Drawings 2-13
3. Operation
3.1 Introduction 3-1
3.2 General Information 3-1
3.3 Control Functionality 3-1
3.3.1 Audio Control Panels 3-1
3.3.2 PTT Keys 3-1
3.3.3 Transmit Priority 3-2
3.3.4 Aural Alerts 3-2
3.3.5 Remote Alert Cancel Switch 3-2
3.3.6 Remote Alert Inhibit Switch 3-2
3.3.7 Audio Muting 3-3
3.3.8 EMERG/BACKUP Indicator 3-3
3.3.9 Passenger Intercom 3-3
3.3.10 Passenger ICS Volume 3-3
3.3.11 Winchman Select 3-3
3.3.12 NORM Call; High Priority Call; ISO Override 3-3
3.3.13 Other Switches and Indicators 3-4
Installation and Operation Manual Page iii
ENG-FORM: 820-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
AMU50-001 Audio Management Unit (AMU50). 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.
Note: This manual contains information applicable to units MOD 12 and above (s/n 3000 and above).
For information applicable to units MOD 11 and below (s/n 2999 and below) contact the product
support department at Northern Airborne Technology Ltd.
1.2 Product Description
1.2.1 System Information
The Digital Audio Communication System (DACS) is a management system that distributes and controls
all of the transceiver, receiver and warning source audio in an aircraft. It enables the transmission of
microphone audio to a selected Transceiver and distributes all Inter-Communication System (ICS) audio.
The primary component of the DACS is the AMU50. Connected to this Line Replaceable Unit (LRU) are
the user headsets, the transceivers, the receivers, and the Audio Control Panels (ACP). The AMU50 also
has an audio accessory port that enables the connection of a unit for providing ICS audio in the cabin.
The DACS architecture is a star configuration to prevent the loss of the entire system due to failure of one
connection. It provides a redundant power supply, redundant amplifiers for the crew microphones (MIC)
and headphones (PHN), redundant amplifiers for the first three direct audio inputs, and multiple modes of
operation.
The Power-On Built-In-Test (PBIT) function provides fault analysis down to the LRU level, while the
Continuous Built-In-Test (CBIT) is a background task that verifies hardware functionality on an ongoing
basis.
1.2.2 System Configuration
The DACS is configurable on a per installation basis using the AMU50 connected via a Universal Serial
Bus (USB) port to a Personal Computer (PC) running the DACS Device Configuration Software (DevCs).
System configuration is stored in the AMU50 and the Remote Memory (RM).
The DevCs is a PC application that allows a user to control adjustments and functions of the DACS
Digital Audio Communication System equipment including the AMU50 and the ACPs. The PC Application
provides a graphical user interface for the display and control of the adjustment levels and function
behaviour or configuration. The configuration can be saved as a file. The configuration can be written to,
and read from, the DACS equipment over a serial data communication buss.
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
1.3 Design Features
The AMU50 is comprised of three subassemblies two of which support two 50 pin D-Min connectors
each. Power distribution, radio, and headset connections are evenly distributed across the connectors to
ensure the loss of one connector does not disable the entire system.
The Audio Management Unit supports up to six separate ACPs. The AMU50 is responsible for providing
power to each ACP53 and completing all of the audio processing to and from the ACP53 including MIC
and PHN audio, user switch selections, and level adjustments. The maximum Receive Audio input level
and the Transmit MIC output level are both adjustable using the DACS DevCs.
The AMU50 provides an audio accessory serial data port for connecting a passenger intercom device.
Support is provided for a Normal ICS Call input, a High Priority ICS Call input, and an Isolation Override
input. The Call inputs are used by passengers without ACP to call the crew when they have been
isolated. When the Isolation Override input becomes active, the Isolation Mode is temporarily suspended
and the passengers can communicate with the crew members.
The Voice Operated ICS (VOX) level for the passengers not assigned to an ACP53 is set in the DACS
DevCs. The highest VOX level threshold shall act as the keyed mode of operation and the VOX circuit
shall not gate the microphone audio. In this mode the MIC audio can only be gated using the ICS PTT
input. When the lowest VOX level is reached, the ICS shall still be gated but shall only require a small
signal to open the ICS channel.
The Audio Management Unit supports six Direct Audio inputs to provide audio at a fixed level to the
users. The Direct Audio inputs heard by each of the users are configurable using the DACS DevCs.
The AMU50 has an eight channel Aural Alert Generator. Each aural alert has a separate key input and
the resultant aural alert signals may be either tone, voice, or tone and voice. The Aural Alert inputs are
configurable, either as active HI or LO using the DACS DevCs.
The AMU50 provides a Direction Finder (DF) Blanking output. This output deactivates the DF antenna to
avoid causing it damage when users transmit on any transceiver.
Two separate power supplies are provided by the AMU50. The primary power supply provides filtering
and pre-regulation before distributing power to the rest of the AMU. The backup power supply provides
power to specific sections of circuitry depending upon the currently selected operational mode.
A USB port is provided on the AMU50 for configuration programming. The port is also used for extracting
the PBIT and CBIT results. The system configuration is downloaded into the AMU50 using the USB port
and is stored in the Remote Memory enabling the replacement of the AMU50 without the need of
downloading a new configuration file.
The AMU50 has three modes of operation: Normal Mode, Backup Mode, and Emergency Mode.
When the system is in Back-up mode, users 1 and 2 maintain full functionality via back-up microphone
and headphone amplifiers but all other headsets and ACPs are disabled. This mode overcomes failures
(such as a crew headset amplifier failure or a failure of circuitry used to support passengers) that may be
adversely affecting the operation of the system.
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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
In Emergency mode all ACPs are deactivated, and only User 1 and User 2 maintain a limited amount of
functionality. In this mode, User 1 will be able to listen to COM1, NAV1, Direct1, Direct2, Direct3 and all
alerts at a fixed level, and transmit on COM1. User 2 will be able to listen to COM2, NAV2, Direct1,
Direct2, Direct3 and all alerts at a fixed level, and transmit on COM2. Both User 1 and User 2 will have
keyed intercom audio at a fixed level.
Emergency mode disables the Digital Signal Processing software and provides the above functionality via
analog technology.
1.4 Specifications
1.4.1 Electrical Specifications
POWER
INPUTS
Audio Inputs
NORM and EMERG Power Inputs
Normal Operating Conditions:
Abnormal Operating Conditions:
Maximum Current: 2.6 A @ 28.0 Vdc with 6 ACPs connected and lights at maximum
Power Outputs for ACP
(ACP 1 PWR thru ACP 6 PWR)
Quantity: Six
Output Voltage: 25.5 Vdc (Nominal) with a +28.0 Vdc input to the AMU50
Maximum Current: 0.25A @ 25.5 Vdc
Power Output for RM01
(RM01 PWR)
Quantity: One
Output Voltage: 5 Vdc ±10% (Nominal)
Maximum Current: 0.10 A @ 5 Vdc
(NORM +28 VDC Power, EMERG +28 VDC Power)
Nominal input voltage 28.0 Vdc
Maximum input voltage 30.3 Vdc
Minimum input voltage 22.0 Vdc
Emergency input voltage 18.0 Vdc
Maximum input voltage 32.2 Vdc
Minimum input voltage 20.5 Vdc
MIC Inputs
Three microphone impedances available: User 1 and User 2 microphone impedances must be
the same; User 3 through User 7 microphone impedances are independently configurable.
Quantity Seven, configured through DevCs application.
Gain Independently adjustable from -9 dB to +6 dB of nominal input
level, +/- 1dB with 15 steps of adjustment
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Microphone (Type One) dynamic
Input Impedance 5 Ω ±30%
Rated Input 250 µVrms nominal to produce rated headphones output
Circuitry Type Differential
Microphone (Type Two) dynamic
Input Impedance 75 Ω ±30%
Rated Input 850 µVrms nominal to produce rated headphones output
Circuitry Type Differential
Microphone (Type Three) amplified dynamic/electret
Input Impedance 150 Ω ±10%
Rated Input 250 mVrms nominal to produce rated headphones output
Circuitry Type Single ended
Direct Audio Inputs
(DIR 1 RX thru DIR 6 RX)
Quantity: Six
Input Impedance: 1000 Ω ±10%
Rated Input: 1 to 19.95 Vrms maximum to produce rated headphones output
Circuitry Type: Differential
Receive Audio Inputs
Quantity: Sixteen (8 transceivers and 8 receivers)
Input Impedance: 1000 Ω ±10%
Rated Input: 1 to 19.95 Vrms maximum to produce rated headphones output
Circuitry Type: Differential
Music Inputs
(MUSIC RIGHT/LEFT RX)
Quantity: Two (one left, one right, summed to produce mono)
Input Impedance: 1000 Ω ±10%
Circuitry Type: Differential
Input Range 1: 400 mVrms nominal
Input Range 2: 2.5 Vrms nominal
Discrete Inputs
All discrete inputs have the following specifications unless stated otherwise.
Logic Active LO, switched ground, no external pull up required
Input Active ≤ +3 Vdc
Maximum Current ≤10 mA
Input Protection Diode protected to +45 Vdc maximum
Transmit Push-To-Talk
(USER 1 TX KEY thru USER 7 TX KEY)
Quantity: Seven
ICS Push-To-Talk Inputs
(USER 1 ICS KEY thru USER 7 ICS KEY)
Quantity: Seven
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Passenger ICS Volume Inputs
Quantity: Two
(PAX VOL +/-)
Aural Alert Cancellation Input
Quantity: One
Aural Alert Inhibit Input
(Alert Inhibit)
Quantity: One
Weight On Wheels Input
(WEIGHT ON WHEELS)
Quantity: One
Normal Mode Enable Input
(ACP 1 NORM MODE and ACP 2 NORM MODE)
Quantity: Two (one for User 1 and one for User 2)
Backup Mode Enable Input
(ACP 1 BACKUP MODE and ACP 2 BACKUP MODE)
Quantity: Two (one for User 1 and one for User 2)
Winchman Select Inputs
(ACP 1 WINCHMAN SELECT thru ACP 3 WINCHMAN SELECT)
Quantity: Three (associated with ACP 1 through ACP 3)
Aural Alert Inputs
(Alert 1 thru Alert 8)
Quantity: Eight
Maximum Current: ≤10 mA
Input Protection: Diode protected to +45 Vdc maximum
Active LO Configuration (configured through the DevCs application):
Logic: Active LO, switched ground no external pull up required
Input Active: ≤+3 Vdc
(Alert Cancel)
Active HI Configuration (configured through the DevCs application):
Logic: Active HI, switched power no external pull down required
Input Active: ≥+18 Vdc
Normal Call Input
(NORM Call in)
Quantity: One
High Priority Call Input
(High Priority Call in)
Quantity: One
Isolation Over-ride Input
(Isolation Over-ride in)
Quantity: One
OUTPUTS
The AMU50 provides the following outputs to the aircraft:
Audio Outputs
Headphone Outputs
Three headphone impedances available: User 1 and User 2 headphone impedances must be the
same; User 3 through User 7 headphone impedances are independently configurable.
Quantity: Seven Mono PHN, configured through DevCs application.
Rated Output: >250 mW into rated load
Circuitry Type: Balanced
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Headphone (Type One)
Load Impedance: 8 Ω ±10%
Output Impedance: ≤2.25 Ω
Headphone (Type Two)
Load Impedance: 150 Ω ±10%
Output Impedance: ≤20 Ω
Headphone (Type Three)
Load Impedance: 600 Ω ±10%
Output Impedance: ≤60 Ω
Transceiver Microphone Outputs
Quantity: Eight
Output Impedance: ≤60 Ω
Circuitry Type: Balanced and AC coupled
Rated Output: 250 mVrms into 50 Ω ±10%
Output Range: 11 mVrms to 1.1 Vrms, ≥160 steps, logarithmic
Composite Audio Output
Quantity: One
Output Impedance: ≤150 Ω
Rated Output: 2.5 Vrms or 500 mVrms into 600 ohms ±10%
Circuitry Type: Balanced
Cockpit Voice Recorder Outputs
(User 1 CVR and User 2 CVR)
User 1 CVR is User 1 summed MIC and headphone audio, and User 2 CVR is User 2 summed
MIC and headphone audio.
Quantity: Two
Load Impedance: 5 kΩ ±10%
Output Impedance: ≤600Ω across rated frequency range
Rated Output: 500 mVrms into rated load in normal mode ±10%
500 mVrms into rated load in emergency mode +50%/-30%
Output Level: Configurable
through DevCs application, providing 40 ±2 dB of control
Output Range:
Normal Mode: 9 mVrms to 900 mVrms, ≥64 steps
Emergency Mode: 10 mVrms to 900 mVrms, 65 steps
Circuitry Type: Balanced
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Discrete Outputs
All the following outputs have these specifications unless stated otherwise.
Logic: Active LO, switched ground
Output Active: ≤2 Ω
Current: 1 A maximum
Transmit Push-To-Talk Outputs
Quantity: Eight
Crew Isolation Output
Quantity: One
Aural Alert Active Output
Quantity: One
DF Blanking Output
Quantity: One
Emergency Mode Active Output
Quantity: One
BI-DIRECTIONAL PORTS
USB Port
Quantity: One USB 2.0 (for programming)
ICS Tieline
The ICS tie line can be configured (using DevCs) for analog or digital operation.
Analog:
Quantity: One
Output Impedance: 2000 Ω +/-10%
Rated Level: 230 mVrms into 1000 ohms +/-15%
Circuitry Type: Balanced
(CREW ISO OUT)
(ALERT ACTIVE)
(DF BLANKING OUTPUT)
(EMERG/BACKUP OUT)
Digital:
Quantity: One
Specification: RS422
Serial Data Protocol: SP/DIF
1.4.1.1 Audio Performance
The AMU50 meets the requirements of FAA TSO-C139, EASA ETSO-C50c and RTCA/DO-214 Class Ib.
Audio Frequency Response: <3dB from 300 - 6000Hz
Volume Controls: 40dB of adjustment (individual receive audio and intercom audio)
30dB of adjustment (master receive audio)
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
1.4.2 Physical Specifications
Height: 56.6 mm (2.23 in) maximum
Depth: 279.4 mm (11.00 in) maximum
Width: 190.0 mm (7.48 in) maximum
Weight: 2 kg (4.4 lbs) maximum
Material and Finish: Conversion coated aluminium
Connectors:
Four 50 pin D-Sub, two male and two female
Jack post locking hardware
Installation: RS-422 Cable: 20.0 m (785.9 in) maximum
RM01 Cable: 0.3 m (11.8 in) maximum
MIC Cable: 5.0 m (196.7 in) maximum
PHN Cable: 5.0 m (196.7 in) maximum
USB Cable: See USB 2.0 Specification
Mounting: Bulkhead Mount: Four 10-32 screws
1.4.3 Environmental Specifications
The AMU50-001 has been tested to the environmental conditions listed below. Environmental categories
for which TSO and ETSO compliance has been demonstrated are listed on the Environmental
Qualification Form in Section 2 of this manual.
Temperature: -40 to +70° C (Operating)
-45 and +85° C (Short Time Operating)
-55 to +85° C (Ground survival)
Altitude: 50,000 feet max
Humidity: 95% non-condensing
Shock: Operational Shock; 6 g for 11 ms
Crash Safety (impulse); 20 g for 11 ms
Crash Safety (sustained); 20 g for 3 s
Vibration: RTCA/DO-160E category [(SBM)(U2FF1)]
1.4.4 Product Approval
1.4.4.1 FAA: TSO-C139
When configured as defined in section 1.4.5 (DACS System Equipment) the Digital Audio Communication
System is approved as follows:
FAA: TSO-C139 (RTCA/DO-214 Class Ib, RTCA/DO-160E, RTCA/DO-178B Level C)
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AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
1.4.4.2 EASA: ETSO-C50c
When configured as defined in section 1.4.5 (DACS System Equipment) the Digital Audio Communication
System, with an AMU50-xxx which has MOD 15 incorporated, is approved as follows:
EASA: ETSO-C50c (RTCA/DO-214 Class Ib, RTCA/DO-160E, RTCA/DO-178B level C)
When configured as defined in section 1.4.5 (DACS System Equipment) the Digital Audio Communication
System, with an AMU50-xxx which does not have MOD 15 incorporated, is approved as follows:
EASA: ETSO-C50c (RTCA/DO-214 Class Ib, RTCA/DO-160E, RTCA/DO-178B level D)
1.4.5 DACS System Equipment
Product approvals listed in section 1.4.4 apply only to DACS systems configured using approved
components as shown below.
1.4.5.1 Required Equipment
System Component
Approved
Part No.
MOD
Audio Management Unit AMU50-xxx MOD 12 and above (Serial No 3000 and above)
Audio Control Panel (ACP 1 and ACP 2) ACP53-xxx MOD 8 and above (Serial No 3000 and above)
ACP54-xxx MOD 2 and above (Serial No 3000 and above)
1.4.5.2 Optional Equipment
System Component
Approved
Part No.
MOD
Audio Control Panel (ACP 3 to ACP 6) ACP51-xxx MOD 2 and above (Serial No 3000 and above)
ACP53-xxx MOD 8 and above (Serial No 3000 and above)
ACP54-xxx MOD 2 and above (Serial No 3000 and above)
Remote Memory RM01-xxx MOD 3 and above (Serial No 3000 and above)
Installation instructions for the Audio Control Panels and Remote Memory are available in the following
manuals: SM75 (ACP53-xxx), SM77 (RM01-xxx), SM81 (ACP51-xxx), SM82 (ACP54-xxx).
Refer to section 2.4.2 Cautions (Installation Limitations) for details of configuration settings required for
TSO-C139 and ETSO-C50c compliance.
Section 1 ends
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