Multitech MT64DSU User manual

Owner’s Manual
P/N 82034802Rev.C
Model MT64DSU
This publication may not be reproduced, in whole or in part, without prior
expressed written permission from Multi-Tech Systems, Inc. All rights
reserved.Copyright © 1998 by Multi-Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representation or warranties with
respect to the contents hereof and specifically disclaims any implied
warranties of merchantability or fitness for any particular purpose.
Furthermore, Multi-Tech Systems, Inc. reserves the right to revise this
publication and to make changes from time to time in the content hereof
without obligation of Multi-Tech Systems, Inc. to notify any person or
organization of such revisions or changes.
Record of Revisions
Revision Description
BManual revised. Additional information on the CompuServe/
(6/10/96) Internet forums; information on Multi-Tech's Fax-Back Service;
documentation of a new DIP-Switch Summary; editorial and
format changesthroughout this manual.
CManual revised. Reproduced using new Owner's Manual
(12/15/98) format. Made technical corrections and editing updates.
Removed all references to 2-wire connector.
TRADEMARKS
Multi-Tech and the Multi-Tech logo are trademarks of Multi-Tech Systems,
Inc.
DATAPHONE is a registered trademark of AT&T.
All brand and product names mentioned in this publication are trademarks
or registered trademarks of their respective companies.
Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112 U.S.A.
[phone] or [phone]
U. S. FAX [phone]
Fax-Back Service 612-717-5888
Technical Support [phone]
BBS [phone] or [phone]
Internet Address: http://www.multitech.com

Contents
Chapter 1 - Introduction and Description
Introduction ................................................................................ 6
About This Manual ..................................................................... 7
DSU Basic Functions ................................................................. 8
DSU Functions..................................................................... 8
CSU Functions..................................................................... 8
Front Panel Indicators ................................................................ 9
Back Panel ............................................................................... 10
Features ................................................................................... 11
Technical Specifications ........................................................... 12
Chapter 2 - Installation and Cabling
Introduction .............................................................................. 14
Unpacking ................................................................................ 14
Safety Warnings ....................................................................... 14
Cabling Procedure ................................................................... 15
DIP Switch Settings.................................................................. 16
Chapter 3 - Testing
Diagnostic Tests ....................................................................... 22
DSU Loopback Test ................................................................. 22
Local Loopback Test................................................................. 23
Digital Loopback Test ............................................................... 24
Local Loopback Test With Test Pattern .................................... 25
Digital Loopback Test With Test Pattern Test ........................... 26
Remote Loopback Test............................................................. 27
Remote Loopback Test With Test Pattern Test......................... 28
DSU Back-to-Back Test............................................................ 29
iii

Chapter 4 - Warranty, Service and
Tech Support
Introduction .............................................................................. 32
Limited Warranty ...................................................................... 32
On-line Warranty Registration .................................................. 32
Tech Support ............................................................................ 33
Recording MultiDSU64K Information ................................. 33
Service 34
The Multi-Tech BBS ................................................................. 34
To log on to the Multi-Tech BBS......................................... 35
To Download a file.............................................................. 35
About CompuServe.................................................................. 36
About the Internet..................................................................... 36
About the Multi-Tech Fax-Back Service ................................... 37
Appendixes
Appendix A -AT Commands and S-Registers.......................... 40
Appendix B -Application Examples.......................................... 51
Appendix C - Interface Signals and Connector Pinouts ........... 56
Appendix D - DIP-Switch Summary ......................................... 62
Appendix E - FCC Regulations for Telephone Line
Interconnection ............................................................... 63
Index
iv

MultiDSU64K
Chapter 1 - Introduction and Description

6
MT64DSU Owner's Manual
Introduction
Welcome to Multi-Tech's new MultiDSU64K a stand-alone integrated
Data Service Unit (DSU), model number MT64DSU, for accessing 4-
wire switched or dedicated digital links (Figure 1-1). The
MultiDSU64K is a compact easy to operate unit with features
allowing flexibility in meeting your transmission requirements. The
unit operates with 56 Kbps DDS (Digital Data Services) or switched
4-wire networks or compatible digital data services, and 64 Kbps
dedicated 4-wire services.
The unit contains V.35 and EIA RS-232C connectors on the back
panel to connect a computer or Data Terminal Equipment (DTE) and
a RJ-48 Line jack to connect to your DDS or compatible digital data
service. The MultiDSU64K supports AT dialing for asynchronous
operation and DTR dialing or V.25bis dialing for synchronous
operation.
CTSCDRD
SD
Send RCV Carrier Clear Request On LineTest
RTS OL TM
Multi-Rate DSU-CSU
DSU64K
®
Figure 1-1. MultiDSU64K

7
Chapter 1 - Introduction and Description
About This Manual
This manual describes the MultiDSU64K and explains how to install
and cable the unit. The information contained in each chapter is as
follows:
Chapter 1 - Introduction and Description
This chapter provides an overview of DSU/CSU basics, information
on power, front panel indicators, back panel connectors, and a list of
the relevant technical specifications.
Chapter 2 - Installation and Cabling
Chapter 2 provides information on connecting the MultiDSU64K to a
computer or DTE device and a DDS network. The chapter provides
a detailed description of each of the MultiDSU64K DIP-Switch
options with all default settings.
Chapter 3 - Testing Your MultiDSU64K
Chapter 3 dicussess the MultiDSU64K's built-in test features.
Chapter 4 - Service, Warranty, Technical Support & BBS
Chapter 4 provides instructions for getting MultiDSU64Ks serviced
at the factory and information on product warranty; information
about Multi-Tech's user Bulletin Board Service ( BBS ), receiving
technical support via the CompuServe/Internet forums and
information on Multi-Tech's Fax-Back Service.

8
MT64DSU Owner's Manual
DSU Basic Functions
A DSU (Data Service Unit) and a CSU (Channel Service Unit) are
typically connected to provide the interface between DTE (Data
Terminal Equipment) and the DDS (Digital Data Service) or other
four-wire networks. A DSU converts data to a bipolar format for
transmission over the digital line. The CSU terminates the user's
digital circuit, does the line conditioning, provides FCC Rules
compliance, and handles the CO (Central Office) loopback
commands. The MultiDSU64K contains the functions of a Data
Service Unit (DSU) and a Channel Service Unit (CSU) in a single
package.
DSU Functions
The DSU encodes data as pulses on the communications line by
converting the customer data stream to bipolar format for
transmission over the digital network.
CSU Functions
The CSU is used to terminate the digital circuit at the customer site.
It performs line conditioning functions, ensures network compliance
with FCC rules, and responds to test commands (either from the
telco central office or from the CSU).
Figure 1-2 shows the MultiDSU64K in a basic DDS network
installation.
Figure 1-2. Basic DSU/CSU Configuration

9
Chapter 1 - Introduction and Description
Front Panel Indicators
The MultiDSU64K has seven diagnostic LED indicators. They are:
DSU64K
CTSCDRD
SD
Send RCV Carrier Clear Request On LineTest
RTS OL TM
Multi-Rate DSU-CSU
®
Figure 1-3. LED Indicators
SD Transmit (Send) Data: This LED blinks when data is
being transmitted, on for a space, off for a mark.
RD Receive Data: This LED blinks when data is being
received, on for a space, off for a mark.
CD Carrier Detect: This LED is lit when a valid signal
from the remote DSU is detected. This indicator is off
if the DSU receives an idle code. If RTS is off at the
remote DSU, then the network sends an idle code to
the local DSU.
CTS Clear To Send: The CTS (Clear to Send) LED lights
when the MultiDSU64K generates a CTS in response
to either an RTS signal received at the DTE connector,
or RTS forced on by the corresponding DIP-Switch.
RTS Request To Send: The RTS LED lights when the RTS
signal is received from the DTE. The DIP-Switch for
RTS Forced On does not affect this indicator. Refer to
Chapter 2 for switch settings.
OL On Line: The OL (On Line) LED lights to indicate the
MultiDSU64K has detected a signal from the network.
TM Test Mode: The TM LED lights when either Local
Loopback (to DTE), Remote Digital Loopback, Digital
Loopback (to line) or Test Pattern DIP-Switches are
enabled. If the Test Pattern DIP-Switch is enabled,
then the TM LED blinks when errors are detected.
When the TM LED is lit, network transmit/receive
operation cannot occur. Refer to the “Diagnostic” Tests
section for more information.

10
MT64DSU Owner's Manual
Back Panel
The cable connections for the MultiDSU64K are made at the back
panel. The input data (DCE interface) is through either an RS-232 or
V.35 connection; and, theDDS network connection is through an
RJ48S line jack.
LINE
OFF
ON
POWER
EIA RS232C
Figure 1-4. Back Panel Connectors
RS-232C Connector
The RS-232C connector is used to connect the MultiDSU64K to a
computer or DTE device.
V.35 Connector
The V.35 connector is used to connect the MultiDSU64K to a
computer or DTE device.
RJ48S Jack
The RJ48 line interface jack is used to connect the MultiDSU64K to
a DDS network.
Multi DSU Loopback Cable
The Multi DSU loopback cable is used to test mux internal
composite link DSU or external DSU.
Power Connector
The Power connector is used to connect the external power supply
to the unit.
On/Off Switch
The power switch provides DC power to the unit when placed in the
ON position and terminates power when placed in the OFF position.