Audio international MSM2912-01 Series User manual

7300 Industry Drive, North Little Rock, AR 72117
Phone: [phone] Fax: [phone]
www.audiointl.com
Installation Manual
MSM2912-01-x
RS-232 / RS-485 Data Bus Converter
Document # 540124
a DeCrane Aircraft Company

Audio International, Inc. MSM2912-01-x Installation Manual
Document # 540124, Rev C, 04/2004 Page 1 of 9
Document Revision History
Rev. Level Date Description
IR 10/1998 Initial Release
A 07/2000 ECN #5102
B 04/2002 Added Product Photo
C 04/2004
Updated Format, Outline Drawing, added metric units to
reference drawing
Reference Documents
Document # Description
522192 Rev IR5 MSM2912-01-x Outline Drawing
Service Bulletin List
Service
Bulletin # Subject Manual Revision
Revision
Date
Table of Illustrations
Section # Description Page #
2.2 Block Diagram – Typical Application 4
6.0 Reference Drawings 9
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. MSM2912-01-x Installation Manual
Table of Contents
Section Description Page
1.0 General Information …………………………………………….. 3
1.1 Introduction ………………………………………………………… 3
1.2 Purpose of the Equipment ……………………………………….. 3
1.3 Optional Equipment ………………………………………………. 3
2.0 Application ………………………………………………………... 3
2.1 Introduction ………………………………………………………… 3
2.2 Block Diagram ..…………………………………………………… 4
3.0 Installation ………………………………………………………… 4
3.1 Prior to Installation ………………………………………………… 4
3.2 Unpacking and Inspection ……………………………………….. 4
3.3 Cautions &Warnings ……………………………………………... 5
3.4 Wiring Requirements ……………………………………………... 6
3.5 Physical Characteristics ………………………………………….. 7
3.6 Electrical Characteristics …………………………………………. 7
3.7 Mating Connector Information …………………………………… 7
3.8 Pinout Assignments and Descriptions ………………………….. 8
3.9 Post-Installation Test ……………………………………………... 8
4.0 Troubleshooting …………………………………………………. 8
4.1 General Troubleshooting Procedures …………………………... 8
4.2 Troubleshooting Chart ……………………………………………. 9
5.0 Specifications …………………………………………………… 9
6.0 Reference Drawings …………………………………………….. 9
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Audio International, Inc. MSM2912-01-x Installation Manual
MSM2912-01-x
RS-232 to RS-485 Data Bus Converter
1.0 General Information
1.1 Introduction
This manual contains information for the proper installation of the Audio
International, Inc. (AI) RS-232 / RS-485 Data Bus Converter,
Model Number: MSM2912-01-x. The “-x” in the model number designates
the type of connector utilized in the module installation. Also included are
physical and electrical characteristics of the unit.
1.2 Purpose of the Equipment
Audio International’s MSM1912-01-x provides the necessary medium to
convert standard RS-232 serial communications to an RS-485 serial
communication format and vice versa for means of providing an interface
to AI’s proprietary RS-485 digital data bus. This active device requires
power, ground, and data bus connections.
1.3 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.
2.0 Application
2.1 Introduction
2.1.1 The MSM2912-01-x is utilized in applications where laptop
computer applications (RS-232 data bus) are required to interface
with AI’s proprietary RS-485 serial data bus devices.
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Audio International, Inc. MSM2912-01-x Installation Manual
2.1.2 The MSM2912-01-x will interface via AI’s proprietary RS-485 serial
data bus protocol for interface to the Data bus 2 standard. The
Data bus 2 standard is defined as being AI’s standard proprietary
RS-485 serial data bus protocol using a 9600 baud communication
rate.
2.1.3 Careful consideration must be utilized when planning the location
for the module. Optimum location would allow for easy and ready
access to this module for laptop computer interface to the RS-232
data bus connections. The various uses of this unit include audio
level adjustments and system power-up configurations.
2.2 Block Diagram-Typical Application
3.0 Installation
3.1 Prior to Installation
The MSM2912-01-x is a simple module to install. 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 and all other audio/video
modules is necessary. Some of the items to consider include:
• Space
• Proximity to other devices (i.e. source equipment)
• Available power supply
• Length of cable runs
• Environmental conditions (temperature, humidity, etc.)
• Location of other aircraft systems (i.e. oxygen delivery)
• Access for service repair (if applicable)
• Convenience for user interface (if applicable)
3.1.2 The MSM2912-01-x shall 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.
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Audio International, Inc. MSM2912-01-x Installation Manual
3.1.3 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
3.2.1 Carefully open the packaging and remove the MSM2912-01-x.
Verify that all components have been included in the package per
the packing list. Inspect the unit for shipping damage.
3.2.2 If damage has occurred during shipping, a claim should be filed
with Audio International WITHIN 24 hours and a Return Request
Authorization Number shall be obtained from AI by contacting the
Repair Department at 501.801.0640. Repackage the unit in its
original packaging materials and return it to AI following instructions
given by the AI representative. Refer to the front cover of this
manual for address. If no return is necessary, retain the packing
list and the packing materials for storage.
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 remove any factory-installed screws. Damage to the units
may result and void any warranties.
3.3.3 DO NOT install near heat sources such as direct sunlight, warm air
exhausts, or heaters.
3.3.4 No scheduled maintenance is required to ensure continued
airworthiness.
3.3.5 ESD (Electro Static Discharge) guidelines shall be followed.
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Audio International, Inc. MSM2912-01-x Installation Manual
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
should 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
Audio International recommends that power and ground wires be
22 AWG minimum. The chassis shall be electrically bonded to the
airframe structure by a conductive mounting point with <0.1 Ω
resistance using <50 Ωimpedance cable. Aluminum wool, nylon
webbing impregnated with aluminum oxide abrasive or fiber bristle
brushes are the approved tools for removing anodized surfaces at
mounting point where the bonding wire is attached. Power and
Ground wires shall be in accordance with NEMA WC 27500 or
equivalent. Protect power wires with circuit breakers or fuses
located close to the electrical power source bus.
3.4.3 AI’s Proprietary RS-485 Data Bus
The MSM2912-01-x is designed to interface with other Audio
International equipment via AI’s proprietary RS-485 serial data bus.
The data bus shall be implemented using a twisted shielded pair
cable in accordance with NEMA WC 27500 or equivalent. The wire
size for the conductors in this cable shall be 22 AWG, MINIMUM.
Shield pins are available for connecting data bus shields when
required.
Refer to AI document 650007 for RS-485 Serial Data Bus design
architecture.
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Audio International, Inc. MSM2912-01-x Installation Manual
3.5 Physical Characteristics
3.5.1 The MSM2912-01-x shall be located away from heat sources,
magnetic fields, direct sunlight, and areas with excessive dust. The
unit shall NOT be mounted to the skin of the aircraft.
3.5.2 Refer to Section 6.0 for unit dimensions and mounting hole sizes.
3.5.3 The unit shall be rigidly mounted to its location using the
appropriate fastening hardware supplied by the installing agency.
3.5.4 When mounting the unit to the aircraft’s frame, allow sufficient
space for mating connectors.
3.6 Electrical Characteristics
3.6.1 Electrical Specifications:
Electrical Power 50 mA @ +28 VDC
Operating Range
+18 and +32 VDC
(power consumption of
<100 mA)
3.6.2 Two (2) 9-pin connectors are located on the front of the unit. P1
provides RS-232 receive, transmit, and signal ground connections.
P2 provides +28 VDC power, ground, and RS-485 data bus
connections.
3.7 Mating Connector Information
All wiring harnesses to the unit shall be supplied and fabricated by the
installing agency.
Model # Mating Connector
MSM2912-01-1 P1 RD9M10JVL0
MSM2912-01-1 P2 RD9F10JVL0
MSM2912-01-2 P1 DEMA-9P wMale Screwlock
MSM2912-01-2 P2 DEMA-9S w/Male Screwlock
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Audio International, Inc. MSM2912-01-x Installation Manual
3.8 Pinout Assignment and Descriptions
P1 (RS-232) P2 (RS-485)
Pin # Description Pin # Description
1 Reserved 1 +28 VDC Power Input
2 Receive Data 2 Ground
3 Transmit Data 3 Data Bus A (HI)
4 Reserved 4 Data Bus B (LO)
5 Signal Ground 5 Data Bus Shield
6 Reserved 6 Reserved
7 Reserved 7 Reserved
8 Reserved 8 Reserved
9 Reserved 9 Reserved
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 power 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 (1) minute and
reapply power.
• Recheck all connections to the unit for security and all harness runs for
possible pinching. Recheck all pinouts for application accuracy.
• Utilizing a voltmeter, oscilloscope, or other voltage instrument, verify
proper input voltage on the data bus pins. Typical measurements with
no device(s) on bus transmitting are as follows:
A-to-Ground : 4.0 to 4.5 VDC
B-to-Ground : 0.1 to 0.2 VDC
If any device is transmitting (i.e., holding bus active), then these typical
measurements would be reversed for the A-to-Ground and B-to-
Ground measurements. This is a helpful troubleshooting tool as this
condition can indicate a data bus lockup.
• The RS-485 data bus is a bi-directional bus that does not have a ‘bus
controller’. The bus uses a differential digital signal transmits only
when commands are entered via switch selection or other system
synchronizing commands. The “A” leg of the bus is HI and the “B” leg
LOW.
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Audio International, Inc. MSM2912-01-x Installation Manual
4.2 Troubleshooting Chart
Problem Possible Cause Solution
Unit not operating 

•
•
Unit improperly
connected between
data buses
No power to unit
Disconnect and reconnect
unit properly
Verify that +28 VDC power
is applied to correct pins
5.0 Specifications
Physical Specifications
Housing Aluminum
Weight Approx. 0.31 lb / 0.14 kg
Dimensions*
(l x w x h)
3.10” x 5.01” x 1.05”
7.87cm x 12.73cm x 2.67cm
* All dimensions given with ±0.03" tolerance.
6.0 Reference Drawings
The following diagrams show the unit dimensions, mounting locations, and
connector locations for the MSM2912-01-x.
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