SEALED
2012.11
.19
17:46:3
2 -08'00'
Installation and Operation Manual
ERU50-001
Emergency Relay Unit
SM83-ERU50-804-0
ISSUE 1.01
IMPORTANT NOTICE
Chelton Avionics Inc. doing business as Wulfsberg Electronics
Division is responsible for full distribution and revisions of
ICA's (Instructions for Continued Airworthiness).
For inquiries regarding the content and currency of this
manual contact Wulfsberg Electronics Division, 6400
Wilkinson Drive, Prescott, Arizona, 86301. Telephone (928)
756-1615 or refer to the following website:
www.wulfsberg.com for more information.
Copyright 2009
Geoff Melton
2012.11.14
18:30:02 -08'00'
Barb Page
2012.11.1
6
09:25:46
-08'00'
Zack
Pahlman
2012.11.
19
15:12:12
-08'00'
ERU50-001 Emergency Relay Unit
SM83 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
1.01 All DCA W12809 Nov 15, 2012
1.00 Section 1 Rev: 1.00
Section
Revision Number
Section 2 Rev: 1.00
Section 3 Rev: 1.00
Revision Description Issue Date
Initial release Oct 22, 2009
Installation and Operation Manual Issue 1.01 Page ii
CONFIDENTIAL AND PROPRIETARY TO COBHAM
ERU50-001 Emergency Relay Unit
SM83 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 1-1
1.4.1 Electrical Specifications 1-1
1.4.2 Physical Specifications 1-3
1.4.3 Environmental Specifications 1-3
2. Installation
2.1 Introduction 2-1
2.2 Unpacking and Inspection 2-1
2.2.1 Warranty 2-1
2.3 Airworthiness Limitations 2-1
2.4 Installation Procedures 2-1
2.4.1 Warnings 2-2
2.4.2 Cautions 2-2
2.4.3 Cabling and Wiring 2-2
2.4.4 Post-Installation Checks 2-2
2.4.5 Functional Requirements 2-3
2.4.6 Minimum Performance Requirements 2-4
2.4.7 Alert Configuration 2-5
2.5 Accessories Required But Not Supplied 2-5
2.6 Installation Drawings 2-5
3. Operation
3.1 Introduction 3-1
3.2 General Information 3-1
Installation and Operation Manual Issue 1.01 Page iii
CONFIDENTIAL AND PROPRIETARY TO COBHAM
ERU50-001 Emergency Relay Unit
SM83 Installation and Operation Manual
Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
ERU50-001 Emergency Relay Unit. All derivative product information shall be contained in the applicable
manual supplement, which may be obtained from Cobham as required.
Review all notes, warnings and cautions.
1.2 Product Description
The ERU50 is an Emergency Relay Unit for use with the Cobham Digital Audio Communication System
(DACS).
1.3 Design Features
The 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 ERU50 allows continued communications between a crew member and cabin crew member when
the DACS is either in Backup or Emergency mode of operation. The ERU50 is a bulkhead mounted unit.
The ERU50 is powered from the corresponding cabin Audio Control Panel (ACP) power output which
comes from the AMU50 Audio Management Unit (AMU). The ERU50 is controlled either by the
corresponding cabin ACP NORM Mode output or by the corresponding AMU ACP power output.
The ERU STATUS DISCRETE functionality is intended for activating an alert on the AMU.
1.4 Specifications
1.4.1 Electrical Specifications
Power Supply
Input Current: 500 mA maximum @ 28.0 Vdc
Normal Operating Conditions:
Nominal: +28.0 Vdc
Maximum: +30.3 Vdc
Minimum: +22.0 Vdc
Emergency: +18.0 Vdc
Abnormal Operating Conditions:
Maximum: +32.2 Vdc
Minimum: +20.5 Vdc
Installation and Operation Manual Issue 1.01 Page 1-1
CONFIDENTIAL AND PROPRIETARY TO COBHAM
Input Signals
Microphone Inputs
Quantity: 2
Circuit Type: Differential, passive feed through
Rated Level: 30 Vrms maximum
Maximum Current: 1A maximum
Headphones Inputs
Quantity: 2
Circuit Type: Differential, passive feed through
Rated Level: 30 Vrms maximum
Maximum Current: 1A maximum
Transmit Key Inputs
Quantity: 2
Maximum Current: 1A maximum
Intercommunication System Key Inputs
Quantity: 2
Maximum Current: 1A maximum
ERU Status Discrete Selection
Quantity: 1
Maximum Current: 1A maximum
ERU50-001 Emergency Relay Unit
SM83 Installation and Operation Manual
AMU ACP 3 Power
Quantity: 1
Rated Input Level: 30 Vdc maximum
Maximum Current: 1A maximum
ACP 3 NORM Mode
Quantity: 1
Rated Level: Active low, <15 mA
Input Protection: Diode protected to +28 Vdc maximum
Output Signals
Microphone Outputs
Quantity: 2
Circuit Type: Differential, passive feed through
Rated Level: 30 Vrms maximum
Maximum Current: 1A maximum
Headphones Outputs
Quantity: 2
Circuit Type: Differential, passive feed through
Rated Level: 30 Vrms maximum
Maximum Current: 1A maximum
Transmit Key Outputs
Quantity: 2
Maximum Current: 1A maximum
Installation and Operation Manual Issue 1.01 Page 1-2
CONFIDENTIAL AND PROPRIETARY TO COBHAM
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