Northern Airborne Technology AMU50-001 - Manual (Page 5)

AMU50-001 Audio Management Unit
SM76 Installation and Operation Manual
Section 1 Rev: 1.03
Issue 1 Page 1-2
ENG-FORM: 800-0116.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
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.