Northern Airborne Technology AMU50-001 - Manual (Page 16)

AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Section 2 Rev: 1.04
Issue 1 Page 2-4
ENG-FORM: 805-0120.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
2.4.4.1 Interconnect References
The Interconnect (AMU50\001\403-0) and Connector Map (AMU50\001\405-0) show standard signal
designations. For information on the correlation between these designations and the Transmit/Receive
signal designations for a specific ACP, refer to the Custom Designation Cross-Reference List
(ACP5x\xxx\724-1) in the Installation and Operation section of the relevant ACP Service Manual.
2.4.4.2 NORM and EMERG Power Inputs
The NORM power input is active when the system is in NORM mode. The EMERG power input is active
when the system is in BK-UP or EMERG modes. If 28 Vdc power is lost on both NORM and EMERG
power inputs then no audio is provided to any user. If audio is required by users 1 and 2 during
emergency electrical system conditions, the EMERG power input must be connected to an aircraft
essential 28 Vdc buss or battery buss.
2.4.4.3 Normal and Backup Mode Inputs
There are two NORM MODE inputs (ACP1 and ACP2) on the AMU50 (one for User 1 and one for User
2). When both of these inputs are active, the system will be in Normal Mode.
There are two BACKUP MODE inputs (ACP1 and ACP2) on the AMU50 (one for User 1 and one for the
User 2). When either of these inputs is active, the system will enter Backup Mode.
When the system is in Backup Mode, users 1 and 2 maintain full functionality via backup microphone and
headphone amplifiers but all other headsets and ACPs are disabled. This mode is to overcome a crew
headset amplifier failure or a failure of circuitry used to support passengers that may be adversely
affecting the operation of the system.
When User 1 or User 2’s Normal Mode and Backup Mode inputs become inactive the AMU50 will enter
Emergency Mode.
In Emergency Mode, all ACPs are deactivated. User 1 and User 2 maintain a limited amount of
functionality however. In this mode, User 1 will be able to listen to COM1, NAV1, Direct1, Direct2, Direct3
and all alerts at a fixed level. User 1 will be able to transmit on COM1. In this mode, User 2 will be able
to listen to COM2, NAV2, Direct1, Direct2, Direct3 and all alerts at a fixed level. User 2 will be able to
transmit on COM2. 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
using analog technology.
2.4.4.4 Routing of Power Lines
RTCA/DO-160E Section 22 Lightning Induced Transient Susceptibility testing of the AMU50 cable
bundles was conducted with the 28 Vdc power lines bundled with the control/signal leads. To maintain the
equipment lightning protection, the power lines must be bundled with the control/signal lines in the aircraft
installation.