Multitech MT56DSU-S User Manual

MT56DSU-S

Syncronous 56K bps

Data Service Unit

User Guide

MT56DSU-S User Guide
PN: S000327A

Copyright ©2003 by Multi-Tech Systems, Inc.
All rights reserved. This publication may not be reproduced, in whole or in part, without prior written permission from Multi-

Tech Systems, Inc.
Multi-Tech Systems, Inc. makes no representations 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.

Revision Date Description

A 12/30/2003 Initial release of MT56DSU-S User Manual on CD.

Trademarks

MultiTech and the MultiTech logo are trademarks of Multi-Tech Systems, Inc. All other references are trademarks of their
respective companies.

Technical Support

France [e-mail] [phone]
India [e-mail] [phone]
U.K. [e-mail] [phone]
U.S., Canada [e-mail] 1 800 972-2439
Rest of World [e-mail] [phone]

World Headquarters

Multi-Tech Systems, Inc.
2205 Woodale Drive
Mounds View, Minnesota 55112 U.S.A.
[phone] or [phone]
U.S. FAX [phone]
Technical Support [phone]
www.multitech.com

Content s

Chapter 1 - Introduction..................................................................................... 5

1.1 Introduction ............................................................................................. 6

1.2 About This Manual .................................................................................. 6

1.3 Description ............................................................................................. 7

1.4 CSU/DSU Basics ................................................................................... 7

1.4.1 DSU Functions .....................................................................................7

1.4.2 CSU Functions .....................................................................................7

1.5 Features ................................................................................................. 8

1.6 Specifications ......................................................................................... 9

Chapter 2 - Front & Back Panel Descriptions................................................ 10

2.1 Introduction ........................................................................................... 11

2.2 Front Panel ........................................................................................... 11

2.3 Back Panel ........................................................................................... 12

2.3.1 POWER Connector .............................................................................12

2.3.2 RS232 Connector................................................................................12

2.3.3 LINE Connector ..................................................................................12

2.4 Switch Settings..................................................................................... 13

2.5 Shunts .................................................................................................. 14

Chapter 3 - Unpacking & Setup....................................................................... 15

3.1 Introduction ........................................................................................... 16

3.2 Unpacking ............................................................................................. 16

3.3 Telecom Safety Warnings ..................................................................... 16

3.4 Setup .................................................................................................... 17

3.5 V.35 Shunt ............................................................................................ 18

Chapter 4 - Diagnostics.................................................................................... 19

4.1 Introduction ........................................................................................... 20

4.1.1 Loopback Test....................................................................................2 0

4.1.2 Line Loopback Test ............................................................................2 1

4.1.3 DSU Loopback Test............................................................................2 1

4.1.4 DSU Back-to-Back Test .....................................................................2 2

Chapter 5 - Service & Warranty....................................................................... 23

5.1 Multi-Tech Systems, Inc. Warranty & Repairs Policies......................... 24

5.1.1 Warranty .............................................................................................24

5.1.2 U.S. and Canadian Customers............................................................ 24

5.1.3 International Customers (outside U.S.A. and Canada)........................2 5

5.1.4 International Distributors.....................................................................2 5

5.2 Repairs ................................................................................................. 26

5.2.1 Repair Procedures for U.S. and Canadian Customers ........................2 6

5.2.2 Repair Procedures for International Customers................................... 26

5.2.3 Repair Procedures for International Distributors..................................27

5.2.4 Replacement Parts .............................................................................27

5.3 Technical Support ................................................................................. 27

5.4 Internet Site .......................................................................................... 27

Appendix............................................................................................................ 28

Appendix A - Application Examples ................................................................ 29

Introduction......................................................................................................29

Local Area Data Set Application ......................................................................2 9

DDS Point-To-Point Application....................................................................... 29

DDS Multipoint (Polled) Application .................................................................3 0

Appendix B - Interface Signals and Connector Pinouts ................................. 31

RJ-48 Connector..............................................................................................31

DB25S Connector ............................................................................................32

DB25S Connector with V.35 Interface .............................................................3 3

Loopback Cable (MTS P/N 45640100)............................................................ 34

Back-To-Back Cable (MTS P/N 45050000)..................................................... 35

Appendix C - Regulatory Information ............................................................. 36

FCC Regulations for Telephone Line Interconnection ......................................36

Canadian Limitations Notice ............................................................................3 7

Chapter 1 - Introduction

6

Chapter 1 - Introduction

1.1 Introduction

The Multi-Tech Systems MultiDSU, model number MT56DSU-S is a synchronous 56 Kbps data service unit
(DSU). As a combined DSU and Channel Service Unit (CSU), it provides a direct connection to the
DATAPHONE

®

Digital Service (DDS) network. The MT56DSU-S connects a synchronous Data Terminal
Equipment (DTE) device to remote equipment using DDS network lines at 56 Kbps speeds for point-to-point
and multi-point service.

Figure 1-1. MultiDSU Modem

1.2 About This Manual

Chapter 1 - Introduction contains an introduction to the MT56DSU-S product and its features and functions.
Chapter 2 - Front and Rear Panel Descriptions provides front panel LED descriptions and rear panel

connector descriptions, DIP-switch settings, and an RS232/V.35 shunt description.
Chapter 3 - Unpacking and Setup provides unpacking, safety warnings, setup procedures, and how to

change the shunt from the default RS232 position to the V.35 position.

Chapter 4 - Diagnostic Testing explains how to set up and run a diagnostic test.
Chapter 5 - Service and Warranty provides instructions on getting service for your MultiDSU at the factory, a

statement of the limited warranty, information about our user bulletin board service, and space for recording
information about your MultiDSU prior to calling Multi-Tech's Technical Support. The final three sections
explain how to use our bulletin board service (BBS), and get support through CompuServe and the Internet.

Appendix A - Application Examples illustrates several DSU/CSU uses that may help in understanding your
particular installation site.

Appendix B - Interface Signal and Connector Pinouts lists the various electronic signals and connector
pinouts related to the MT56DSU-S.

Appendix C - Regulatory Information

7

Chapter 1 - Introduction

1.3 Description

The MT56DSU-S is compact, easy to operate and has the features to allow flexibility in meeting your
transmission requirements. The DDS is a service for transmission of digital signals via digital transmission
facilities exclusively. The MT56DSU-S is designed to meet AT&T Technical Publication 62310 requirements.
As such, the MT56DSU-S provides all the functions required on the customer side of the network.

You will find the MT56DSU-S easy to install, use and maintain. It is recommended that you read the entire
manual early in your experience with the MT56DSU-S so you can appreciate all of the MT56DSU-S features
and options.

1.4 CSU/DSU Basics

A DSU (Data Service Unit) and a CSU (Channel Service Unit) are typically connected to provide the interface
between DTE (data terminal equipment) and a DDS or other four-wire network.

The DSU processes serial synchronous digital data over the DDS network or other four-wire unloaded
twisted-pair network.

The MT56DSU-S contains the functions of a DSU and CSU in a single package.

1.4.1 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.

1.4.2 CSU Functions

The CSU terminates 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 (CO)
or from the DSU).

The figure below shows the MT56DSU-S in a basic DDS network installation.

DTE

DDS

Network

DTE

DSU

DSU

Figure 1-2. Basic DSU/CSU Configuration

8

Chapter 1 - Introduction

1.5 Features

The MT56DSU-S provides many useful features. Standard features include V.35 and EIA-232-D interfaces on
the data port (DTE device) and a synchronous rate of 56 Kbps on both the data port and trunk, and user­selectable clocking option.

Your Multi-Tech DSU/CSU provides the following features:

 Supports direct connection to the DATAPHONE Digital Data Service (DDS) or compatible network
 Standard EIA-232-D and V.35 interfaces on the data port (DTE device) and DDS interface on the line

• Multiple selectable clocking

- Internal clocking

- DDS (slave) clocking

• Multiple MT56DSU-S-activated diagnostic tests

- Local loopback test

- Digital loopback test

• Multiple Telco-activated diagnostic tests

- DSU loopback test

- CSU loopback test

9

Chapter 1 - Introduction

1.6 Specifications

Model Number: MT56DSU-S
Device Operation: combined DSU and CSU
Data Rates:
Synchronous 56 Kbps (Data port and line)
Interfaces:

Data (RS232) DB25S (female) - Data port
Data (V.35) DB25S (female) - Data port with an adapter cable

Line (DDS) RJ-48 8-position keyed jack - Line
Power Requirements: 115V AC, 50-60 Hz, 2 Watts
Temperature: 32 to 120° F (0 to 50° C)
Humidity: 20 to 90% (non-condensing)
Dimensions: 1" H x 4.125" W x 5.5" D

2.5 cm H x 10.8 cm W x 14.2 cm D

Weight: 8 oz. (224 g)
Certification: FCC Part 15 Class B

FCC Part 68
UL Listed

Compatibility: AT&T Pubs 62310
FIC Codes: 04DU5-56
USOC Jack: RJ-48S
Transmitter/Receiver:

Modulation bipolar return to zero (BRZ)

Transmit Level 1.4V peak (+6dBm) into 135 Ohm at 56 Kbps

Output Impedance 135 ohms

Receive Levels +6 to -45 dBm

Input Impedance 135 ohms

Delay Times (in secs.)

RTS/CTS DCD on DCD off

0.4 0.3 0.2

Chapter 2 - Front & Back

Panel Descriptions

11

Chapter 2 - Front & Back Panel Descriptions

2.1 Introduction

This chapter describes the front panel LEDs and back panel connectors. The front panel has one row of
LEDs. Two back panel connectors provide the data and DDS or LADS connections. A circular power
connector is provided to connect the external power supply.

2.2 Front Panel

The front panel has five LEDs that provide the status of the line. The V35 LED lights if V.35 interface signaling
is used. The line LEDs display status whether the line is transmitting or receiving frames, and line status.

Figure 2-1. Front Panel

TD Transmit Data (TD) LED blinks when data is being transmitted - on for a space and

off for a mark.

RD Receive Data (RD) LED blinks when data is being

received - on for a space and off for a mark.

V35 The V35 LED lights when the shunt is in the V35 position.
NS The No Signal (NS) LED lights when no signal is received from the network or when

the signal is too weak for normal operation.

OOS The Out Of Service (OOS) LED lights when an outage condition occurs. This

happens when there is a failure in the digital service that is detected by the network
and the Telco sends a repetitive OOS sequence.

CD The Carrier Detect (CD) LED lights when a carrier signal is received from the

network.

12

Chapter 2 - Front & Back Panel Descriptions

2.3 Back Panel

All the cable connections, including one power connection and two signal connections, are made at the back
panel of the DSU. The RS232 connector is used to connect the DSU to an RS232 or V.35 device, and the
LINE connector connects to a DDS or LADS (Local Area Data Set) circuit. The cable connections are shown
in Figure 2-2 and defined in the following sections.

POWER

LINE

RS232

Figure 2-2. Back Panel

2.3.1 POWER Connector

The POWER connector is used to connect the external wall type transformer power supply to the DSU. The
wall transformer plugs directly into an AC outlet.

2.3.2 RS232 Connector

The RS232 (Data) connector is used to connect the DSU to a sync device, such as, multiplexers, routers, or
legacy equipment such as cluster controllers. The RS232 connector is a DB-25 female connector located on
the back panel of the DSU.

The RS232 data connector interface can be switched to a V.35 interface. For the V.35 interface, an internal
data shunt has to be moved from the default RS232 position to the V.35 position. To change the shunt, refer
to the "Shunt" paragraph in this chapter. Also refer to Appendix A for special cabling requirements for the
V.35 mode.

2.3.3 LINE Connector

The LINE connector is used to connect the DSU to a 56K DDS circuit or LADS. This connector is an RJ-48
(keyed) jack on the back panel of the unit.