Audio international MSM2912-02-x User manual

7300 Industry Drive, North Little Rock, AR 72117
Phone: [phone] Fax: [phone]
www.audiointl.com
Installation Manual
Model #: MSM2912-02-x
RS232 / RS485 Data Bus Converter
Document #540182

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 2 of 10
Document Revision History
Rev. Level Date Description
IR 2/2000 Initial Release
Reference Documents
Document # Drawing # Description
N/A 522192 MSM2912-02-x Outline Drawing
Service Bulletin List
Service
Bulletin # Subject Manual Revision Revision Date
Table of Illustrations
Illustration # Description Page #
1 Typical Application 5
2 Reference Drawings 10
PROPRIETARY INFORMATION NOTICE: Despite any other copyright notice, this document and
information disclosed herein contains confidential, proprietary designs owned by Audio
International, Inc. Neither this document nor the data contained herein shall be reproduced, used
or disclosed to anyone without the written authorization of Audio International, Inc.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 3 of 10
Table of Contents
Section Description Page
1.0 General Information ……………………………………………. 4
1.1 Introduction ……………………………………………………….. 4
1.2 Purpose of the Equipment ………………………………………. 4
1.3 Operational Features …………………………………………….. 4
1.4 Optional Equipment ……………………………………………… 4
2.0 Application ……………………………………………………….. 5
2.1 Introduction ……………………………………………………….. 5
2.2 Block Diagram –Typical Application …………………………… 5
3.0 Installation ……………………………………………………….. 5
3.1 Prior to Installation ……………………………………………….. 5
3.2 Unpacking and Inspection ………………………………………. 6
3.3 Cautions & Warnings …………………………………………….. 6
3.4 Wiring Requirements …………………………………………….. 6
3.5 Physical Characteristics………………………………………….. 7
3.6 Electrical Characteristics…………………………………………. 8
3.7 Mating Connector Information ……………..……………………. 8
3.8 Pinout Assignment Descriptions ………………………………... 8
3.9 Post-Installation Test …………………………………………….. 8
4.0 Troubleshooting Guide………………………………………… 9
4.1 General Troubleshooting Procedures ………………………….. 9
4.2 Troubleshooting ………………………………………………….. 9
5.0 Specifications …………………………………………………… 9
5.1 Unit Specifications ……………………………………………….. 9
6.0 Reference Drawings ……………………………………………. 10

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 4 of 10
MODEL # MSM2912-02-x
RS232 / RS485 Data Bus Converter
1.0 General Information
1.1 Introduction
This manual contains information for the proper installation of the Audio
International, Inc. (AI) RS232 / RS485 Data Bus Converter, Model Number
MSM2912-02-x. The “-x”in the model number designates the type of
connector utilized in installation. Also included are physical and electrical
characteristics of the unit.
1.2 Purpose of the Equipment
The MSM2912-02-x provides the necessary medium to convert standard
RS232 serial communications to an RS485 serial communication format
and vice versa for means of providing an interface to AI’s proprietary
RS485 digital data bus. This unit is an active device that requires power,
ground, and data bus connections.
Strapping pins are provided to enable the unit to address internal firmware
that will allow the operator/installation agency to use multiple RS232
controlled units on the same AI proprietary RS485 digital data bus.
1.3 Operational Features
Listed below are key features of the MSM2912-02-x:
q Operates between +18 and +32 VDC with a power consumption of less
than 100mA
q Active device requiring only power, ground, and data bus connections
q Compact, lightweight
q Lightweight aluminum construction
1.4 Optional Equipment
Audio International, Inc. offers a comprehensive family of Cabin Control
Modules. These modules provide convenient solutions for a variety of
frequently encountered interfacing needs or special requirements and are
an important part of AI’s “building block”system for configuring total cabin
management.
Contact your AI representative for details.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 5 of 10
2.0 Application
2.1 Introduction
The MSM2912-02-x is utilized in applications where laptop computer
applications (RS232 data bus) are required to interface with AI’s
proprietary RS485 serial data bus devices.
The MSM2912-02-x will interface via AI’s proprietary RS485 serial data
bus protocol for interface to the Databus 2 standard. The Databus 2
standard is defined as being AI’s standard proprietary RS485 serial data
bus protocol using a 9600 baud communication rate.
With all strap pins open, the unit will operate in an identical manner to the
existing AI module MSM2912-01-x. The strapping options allow the unit to
address internal firmware to allow the operator / installation agency to use
multiple RS232 controlled units on the same AI proprietary RS485 data
bus.
2.2 Block Diagram –Typical Application

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 6 of 10
3.0 Installation
3.1 Prior to Installation
Prior to installation, the following items should be considered:
3.1.1 During the design and layout of the aircraft cabin, careful
consideration of the location of this module is necessary. Some of
the items to be considered include:
• Space
• Available power supply
• Environmental conditions (temperature, humidity, etc.)
• Length of cable runs
3.1.2 The MSM2912-02-x must be installed to conform to the standards
designated by the customer, installing agency, and existing
conditions as to the unit location and type of installation.
3.1.4 Mounting screws are required to secure the unit. Refer to Section
6.0, Reference Drawings, for mounting hole diameters and
configuration.
3.2 Unpacking and Inspection
Carefully open the packaging and remove the unit. Verify that all
components have been included in the package per the packing list.
Inspect the unit for damage. Retain the packing materials and packing
list.
If damage has occurred during shipping, a claim must be filed with AI
within 24 hours and a “Return Request Authorization Number”must be
obtained from AI. Refer to the front cover of this manual for address and
telephone number of Audio International. Repackage the unit in its
original packaging materials and return it to AI following instructions given
by the AI representative. If no return is necessary, retain the packing
materials for storage or reshipment if necessary.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 7 of 10
3.3 Cautions and Warnings
3.3.1 It is important to do a pin-to-pin power and ground check on all
connectors. Ensure that power and ground are applied only where
specified. Damage to the unit may result if power or ground is
applied to the wrong points.
3.3.2 DO NOT connect or disconnect the module while power is applied.
3.3.3 DO NOT remove any factory-installed screws. Damage to the units
may result and void any warranties.
3.3.4 ESD (Electro Static Discharge) guidelines shall be followed.
3.4 Wiring Requirements
3.4.1 Introduction
The installing agency shall supply and fabricate all external cables
and mating connectors. The length and routing of external cables
must be carefully studied and planned before attempting installation
of the equipment. Allow adequate space for installation of cable
and connectors. Avoid sharp bends and placing cables near
aircraft control cables. Maintain a minimum clearance of three (3)
inches from any control cable. If wiring is run parallel to
combustible fluid or oxygen lines, maintain a separation of six (6)
inches between the lines.
3.4.2 Power Wires
All power and ground wires shall be 22 AWG, minimum. Power
ground wires shall be grounded within twelve (12) inches of the
unit. All wires shall be in accordance with MIL-W-22759 or
equivalent. Twisted, shielded cable shall be in accordance with
MIL-W-27500 or equivalent. Protect power wires with circuit
breakers or fuses located close to the electrical power source bus.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 8 of 10
3.4.3 AI’s Proprietary RS485 Serial Data Bus
The MSM2912-02-x is designed to interface with other AI
equipment via AI’s proprietary RS485 serial data bus. This is a bi-
directional data bus that allows multiple units to be connected
simultaneously.
The data bus is to be implemented using a twisted shielded pair
cable in accordance with MIL-W-27500 or equivalent. The wire
size for the conductors in this cable is to be 22 AWG (minimum).
The shield is to be connected wherever a shield pin is provided.
Shield terminations are to be made as close to the connector pin as
possible. In the event shield pins are not provided, the data bus
shield shall be terminated per AI’s proprietary RS485 specification.
All modules on AI’s proprietary RS485 serial data bus shall be
connected in a “daisy-chain”configuration. AI’s proprietary RS485
serial data bus specification is available upon request.
3.5 Physical Characteristics
3.5.1 Refer to Section 5.0 for unit dimensions.
3.5.2 Refer to Section 6.0 for attachment points.
3.5.3 When mounting the unit, allow sufficient space for mating
connectors.
3.6 Electrical Characteristics
3.6.1 Refer to Section 5.0 for electrical specifications.
3.6.2 Two connectors are available on the MSM2912-02-x. P1 provides
RS232 data bus commands: receive data, transmit data, and signal
ground. P2 provides AI’s proprietary RS485 serial data bus
commands, +28 VDC power, ground, and ID strapping pins.
Device ID pins on connector P2 are used to provide a unique
address on AI’s proprietary RS485 serial data bus. These are
binary ID pins and will allow up to eight (8) MSM2912-02-x modules
to be installed on the aircraft’s AI proprietary RS485 serial data bus.
Since the first ID number is 0, device ID pin connections are not
required when only one unit is used. If more than one unit is
configured on the data bus, connect the respective device ID pins
to ID common.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 9 of 10
3.7 Mating Connector Information
All wiring harnesses to the unit are supplied and fabricated by the
installing agency.
Model # Pin # Mating Connector
MSM2912-02-1 P1 RD9M10JVL0
P2 RD9F10JVL0
MSM2912-02-2 P1 DEMA-9P w/Male Screwlocks
P2 DEMA-9S w/ Male Screwlocks
3.8 Pinout Assignment Descriptions
P1 (RS232) P2 (RS485)
Pin # Description Pin # Description
1 N/C 1 + 28 VDC
2 Receive Data 2 Ground
3 Transmit Data 3 Data Bus (A)
4 N/C 4 Data Bus (B)
5 Signal Ground 5 Data Bus Shield
6 N/C 6 ID Common
7 N/C 7 ID 1
8 N/C 8 ID 2
9 N/C 9 ID 3
3.9 Post-Installation Test
Verify that the data bus conversion commences and appropriate
equipment is operational.
4.0 Troubleshooting Guide
4.1 General Troubleshooting Procedures
Many problems can be isolated with the following general techniques:
• To verify power to the unit, recheck +28 VDC is applied to the proper
pins on the unit. Use a voltmeter to verify correct level.
• Reset by removing power from the unit for at least one minute and
reapply power. Verify the problem still exists.
• Recheck all connections to the unit for security. Check all harness
runs for possible pinching. Recheck all pinouts for application
accuracy.
4.2 Troubleshooting
Should difficulties arise in the installation or operation of the unit, contact
AI Product Support for assistance.

Audio International, Inc. MSM2912-02-x Installation
Document #540182, Rev. IR, 2/2000 Page 10 of 10
5.0 Specifications
5.1 Unit Specifications
Physical Specifications
Housing Aluminum
Dimensions
(L x W x H) 3.10”x 5.01”x 1.05” 7.84cm x 12.73 cm x 2.67cm
Weight 0.36 lbs / 0.16 kg
Electrical Specifications
Power 30 mA at +28 VDC
Operating Range +18 VDC & +32 VDC
(power consumption of <100 mA
6.0 Reference Drawings
The following diagrams show the unit dimensions and connector locations for the
MSM2912-02-x. All dimensions are shown in inches. Refer to Section 5.1 for
metric conversions.