MultiDSU56K TM Rack Mount Multi-Rate DSU Model MT56DSU-R Owner's Manual 82023101.
Owners Manual P/N 82023101, Rev. B Model No. MT56DSU-R 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 © 1995, by 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.
Contents Chapter 1 - Introduction and Description 1.1 1.2 1.3 1.4 Introduction ............................................................................... 6 About This Manual ................................................................... 6 Description ................................................................................ 7 CSU/DSU Basics ..................................................................... 8 1.4.1 DSU Functions ............................................................
3.3 3.4 3.2.11 Normal/Diagnostics ..................................................... 28 LED Indicators ........................................................................ 29 Functions ................................................................................. 29 3.4.1 Local Area Data Set Applications ............................. 29 3.4.2 Off-Net Extension Applications ................................. 30 Chapter 4 - Troubleshooting 4.1 4.2 Introduction .....................................
MultiDSU56K TM Chapter 1 - Introduction and Description 82023101.
MT56DSU-R Owner's Manual 1.1 Introduction Congratulations! Your new MT56DSU-R is one of the finest DSU/ CSUs available today. As a combined CSU (Channel Service Unit) and DSU (Data Service Unit), it provides a direct connection to the DATAPHONE® Digital Service (DDS) network. The MT56DSU-R connects a computer or Data Terminal Equipment (DTE) to remote equipment using DDS network lines at 2400, 4800, 9600, 19200 and 56000 bps speeds for point-to-point and multi-point service. 1.
Chapter 1 - Introduction and Description 1.3 Description The MT56DSU-R is a rack-mounted DSU/CSU that is 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-R is designed to meet AT&T Technical Publication 62310 requirements. As such, the MT56DSU-R provides all of the functions required on the customer side of the network.
MT56DSU-R Owner's Manual 1.4 CSU/DSU Basics A DSU (Data Service Unit) and a CSU (Channel Service Unit) are typically connected to provide the interface between a DTE (data terminal equipment) and the DDS (Digital Data Service) or other four-wire network. The DSU is used to process serial synchronous or asynchronous digital data over the DDS network or other four-wire unloaded twisted-pair wiring network.
Chapter 1 - Introduction and Description 1.5 Features The MT56DSU-R provides many useful features. Standard features include V.35 and RS232 connections and either synchronous and asynchronous transmission; synchronous at rates up to 56000 bps and asynchronous up to 19200 bps; selectable digital data rates that match the services offered by the carriers.
MT56DSU-R Owner's Manual 1.6 FCC Regulations for Telephone Line Interconnection 1. This equipment complies with Part 68 of the FCC rules. On the outside surface of the rack is a label that contains, among other information, the FCC registration number and ringer equivalence number (REN). If requested, this information must be provided to the telephone company. 2. As indicated in Appendix B, the suitable jack (USOC) connection arrangement for this equipment is shown.
Chapter 1 - Introduction and Description 7. No repairs are to be made by you. Repairs are to be made only by Multi-Tech Systems or its licensees. Unauthorized repairs void registration and warranty. 8. This equipment cannot be connected to public coin service provided by the telephone company. (Contact the state public utility commission, public service commission or corporation commission for information.) Manufacture: Multi-Tech Systems, Inc. Model number: MT56DSU-R FCC Registration No.
MT56DSU-R Owner's Manual 1.7 Specifications Model Number MT56DSU-R Device Operation combined DSU and CSU Data Rates Synchronous Asynchronous 2400, 4800, 9600, 19200, 56000 bps 2400, 4800, 9600, 19200 bps Interfaces RS232C, V.35, DDS Temperature 0 to 50o C Humidity 95% (non-condensing) Dimensions 0.75" H x 5.5" W x 10.4" D 1.8 cm H x 13.5 cm W x 26 cm D Weight 0.6 Lbs. (0.3 Kg.
Chapter 1 - Introduction and Description Input Impedance 135 ohms Delay Times (in msecs.) RTS/CTS DCD on DCD off 2400 4800 9600 19200 56000 8.1 4.3 2.2 1 0.4 7.5 2.6 1.6 0.8 0.3 7.0 3.5 1.5 0.7 0.2 13 82023101.
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MultiDSU56K TM Chapter 2 -Hardware Installation 82023101.
MT56DSU-R Owner's Manual 2.1 Introduction This chapter provides the information needed to configure and install the MT56DSU-R in a Multi-Tech Systems CC216G modem rack. This manual assumes the reader is familiar with the function and operation of data communications equipment and is technically qualified to provide installation service. 2.
Chapter 2 - Hardware Installation 2.2.1 12 -Position DIP Switch (# 1-12) The 12-position DIP switch is used to set data rate, clocking, RTS control, DSR control, and Async/Sync operation, diagnostic modes (Loopback Test, Test Pattern ), Circuit Assurance, and System Status. The default settings are shown in Table 2-1. If you want to make changes to one of these settings, refer to section 2.3. 2.2.
MT56DSU-R Owner's Manual 2.3 Changing the Default DIP Switch Settings Use Table 2-1 to determine the DIP switch setting changes required for your MT56DSU-R to operate in your particular environment. You may want to record your switch setting changes for future reference (e.g., troubleshooting, equipment moves/changes, calling Tech Support). The DIP switches are illustrated in Figure 2-1. The factory default settings are indicated by an * in the Table 2-1. Table 2-1.
Chapter 2 - Hardware Installation Table 2-1.
MT56DSU-R Owner's Manual 2.4 Installation Procedure After your CC216G modem rack has been installed in your computer cabinet or in a stand-alone cabinet of your choosing, the MT56DSUR can be inserted into the rack. Refer to the Rack Mounted Modems Owner's Manual for rack installation procedures. Then, perform the following procedure in Table 2-2 to install the MT56DSU-R. Table 2-2. Installation 1. Verify that the DIP switches on the MT56DSU-R are set for your particular configuration; refer to Table 2-1.
Chapter 2 - Hardware Installation Table 2-2. Installation (cont'd) 7. To connect the DTE to the MT56DSU-R using a V.35 interface, connect the V.35 Interface Adapter cable (CADSUR35) supplied by Multi-Tech to the V.35 interface on the DTE and the other end to the DB25 connector on the back of the rack. Refer to Appendix A in this manual for V.35 Interface Adapter cable information. Refer to the Rack Mounted Modems Owner's manual for cable connections on the rack. 8.
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MultiDSU56K TM Chapter 3 - Operation 82023101.
MT56DSU-R Owner's Manual 3.1 Introduction This chapter provides information on the operating functions of the MT56DSU-R. During normal operation the MT56DSU-R requires no operator intervention. Many of the optional features of the MT56DSU-R are selected by setting a switch. Please refer to changing the default DIP switch settings in Installation (Chapter 2) to change your particular environment. 3.
Chapter 3 - Operation 3.2.3 Anti-Streaming This option is typically enabled on remote DSUs using multi-point lines. When enabled, the anti-streaming feature prevents a streaming (jammed) DTE from affecting the communications from remote sites(in a multi-point circuit) that are operating properly. When Anti-Streaming is enabled, the MT56DSU-R will detect when the DTE device holds RTS (Request To Send) on for longer than 20 seconds.
MT56DSU-R Owner's Manual 3.2.5 System Status With this option enabled, the MT56DSU-R conditions the DSR signal with additional parameters to provide added information to the connected DTE concerning the Ready status of the communications channel. Normally when this option is enabled, this signal is on when the MT56DSU-R is powered on and not in test mode.
Chapter 3 - Operation 3.2.7 Clocking This option allows selection of the MT56DSU-Rs clocking (timing for synchronization) from one of three sources. These clocking sources are discussed below. Internal clocking enables the MT56DSU-R to accept timing from its internal timing oscillator. External clocking allows the MT56DSU-R to derive timing from any external device that can supply timing to the External Transmit Clock line on the MT56DSU-Rs DTE interface connector. This external clock must be within 0.
MT56DSU-R Owner's Manual 3.2.9 DSR Forced On When this option is enabled, the MT56DSU-R forces the DSR signal on continuously regardless of the condition of the received DDS signal (OOS or Test). The permanent DSR signal is used to eliminate momentary link interruptions that may be interpreted by the DTE as a communications channel failure. With this option disabled, the DSR is handled as described in the System Status section earlier in this chapter. The default for this function is DSR Forced On.
Chapter 3 - Operation 3.3 LED Indicators The front panel of the MT56DSU-R contains ten LED indicators that can help in troubleshooting network or device problems. Chapter 4 of this manual contains detailed information on the LED indicators. 3.4 Functions This section describes the two optional MT56DSU-R modes of operation.
MT56DSU-R Owner's Manual Data Rate 2400 bps 4800 bps 9600 bps 19200 bps 56000 bps 19 AWG 22.0 19.0 15.0 11.9 10.0 Wire Gage 22 AWG 15.0 13.0 10.0 7.0 6.0 24 AWG 12.0 10.0 7.0 5.0 4.2 26 AWG 9.5 miles 8.0 miles 5.5 miles 4.0 miles 3.0 miles Note that line characteristics will vary depending on cable type/ manufacturer, splices, bridge taps, etc. An example of a typical LADS application is shown in Appendix A of this manual. 3.4.
MultiDSU56K TM Chapter 4 - Troubleshooting 82023101.
MT56DSU-R Owner's Manual 4.1 Introduction All of the indicators used in normal operation of the MT56DSU-R are labeled on the LED overlay on the rack door. Each LED is labeled, as explained below. The LEDs provide status and maintenance information on the MT56DSU-R, as well as the attached network and line. There are no door switches on the MT56DSU-R. 4.2 LED Indicators The door contains ten LEDs each with a two- or three-letter overlay describing its meaning.
Chapter 4 - Troubleshooting 4.2.1 RCV Indicator The RCV (Receive) LED lights when the MT56DSU-R receives data ( 0 or a space) from the network. This LED should appear to flash during normal data reception. 4.2.2 XMT Indicator The XMT (Transmit) LED lights to indicate the DTE is sending data (0 or a space) across the DTE connector. This LED should appear to flash during normal data transmission. 4.2.
MT56DSU-R Owner's Manual 4.2.7 RTS Indicator 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. 4.2.8 NS Indicator The NS (No Signal) LED lights when no signal at all is received from the network, or when the signal is too weak for normal MT56DSU-R operation. This indicator will also flash to indicate that errors have been detected when using the Test Pattern diagnostic feature. 4.2.
Chapter 4 - Troubleshooting 4.3 Diagnostic Tests The MT565SU-R is set to a default of Normal (non-diagnostic) mode at the factory. When diagnostics are to be run, change the DIP switches as described in Chapter 2 of this manual. When a failure occurs in the digital facility (telco equipment), the network will detect the failure and send a repetitive OOS signal sequence to your equipment. Your equipment can detect local loop failure by the absence or distortion of the digital signal.
MT56DSU-R Owner's Manual 4.3.2 Digital Loopback Test This test allows you to test the local DTE, the local MT56DSU-R, the communications link, and the remote MT56DSU-R. Use the following steps to perform the Digital Loopback Test. 1. Set DIP switch #9 on the remote MT56DSU-R to the down position. 2.The Test (TM) LED lights, and if you send data from the local DTE, it should be looped back to the local DTE. If you have access to a Bit Error Rate Tester, this can be used in place of the local DTE.
Chapter 4 - Troubleshooting 4.3.3 Digital Loopback With Test Pattern Test This test allows you to test the local MT56DSU-R, the communications link, and the remote MT56DSU-R. Use the following steps to perform the Digital Loopback Test with the Pattern Test. With this test enabled, the MT56DSU-R sends and detects a predefined 15-bit pseudo-random test pattern. When an error is detected by the MT56DSU-R, the NS (No Signal) LED flashs. 1. Set DIP switch #9 on the remote MT56DSU-R to the down position 2.
MT56DSU-R Owner's Manual 4.3.4 Test Pattern Test This test allows you to test the local MT56DSU-R, the communications link, and the remote MT56DSU-R. With this test enabled, the MT56DSU-R sends and detects a predefined 15-bit pseudo-random test pattern. When an error is detected by the MT56DSU-R, the NS (No Signal) LED flashs. To enable the Test Pattern Test, perform the following. 1. Set the DIP switch # 10 on both the local and remote MT56DSU-R boards to the down position. 2.
Chapter 4 - Troubleshooting 4.3.5 DSU Loopback Test This test lets you verify proper MT56DSU-R operation by matching a transmitted signal to the "looped-back" receive signal. Refer to Appendix B for cable description. 1. Obtain a DSU Loopback cable (CADSURLB) from Multi-Tech, or assemble one. Refer to Appendix B for instructions on building the Loopback cable . 2. Plug the Loopback cable into the DB9 connector on the DSU being tested. 3.
MT56DSU-R Owner's Manual 4.3.6 DSU Back-to-Back Test This test lets you connect two MT56DSU-Rs with a back-to-back cable to verify proper DSU operation. Using a DSU that is known to be operational, you can test a second DSU that is suspect. 1. Obtain a DSU Back-to-Back cable (CADSURBB) from MultiTech, or assemble one. Refer to Appendix B for instructions on building the Back-to-Back cable . 2. On the good DSU board, set DIP switch #9 to the down position. 3.
MultiDSU56K TM Chapter 5 - Warranty, Service and Tech Support 82023101.
MT56DSU-R Owner's Manual 5.1 Service In the event service is required, equipment may be sent, freight prepaid, to our factory. Return shipping charges will be paid by Multi-Tech Systems. Include a description of the problem, a return shipping address, and a check or purchase order for out-of-warranty repairs. The standard repair charge for an MT56DSU-R is $125. Multi-Tech pays the return freight. Send equipment to this address: MULTI-TECH SYSTEMS, INC.
Chapter 5 - Warranty, Service and Tech Support 5.3 Tech Support and BBS Multi-Tech has an excellent staff of tech-support personnel available to help you get the most out of your Multi-Tech product. If you have any questions about the operation of this unit, please call TechSupport at 1-800-972-2439 in the U.S. and Canada. Multi-Tech Systems also maintains a Bulletin Board Service (BBS) for its customers.
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MultiDSU56K TM Appendixes 82023101.
MT56DSU-R Owner's Manual Appendix A - Application Examples Introduction This section illustrates several types of applications in which the MT56DSU-R is typically used. These types include: DDS point-to-point application, DDS multi-point (polled) application, Local Area Data Set, External Clocking application, and Analog Off-Net Extension application DDS Point-To-Point Application In this application, the MT56DSU-R provides the interface between the DDS line and the DTE at your site.
Appendix A - Application Examples DDS Multi-Point (Polled) Application Since your Central Office (CO) equipment must include Multi-point Junction Units (MJUs) and other special arrangements for this type of service, you may need to coordinate efforts with your network service provider. The MT56DSU-R at the host end is the Master Station (also called the Control Station), which typically has RTS forced on. The attached MT56DSU-Rs are called "Remote stations and have RTS controlled by the DTE.
MT56DSU-R Owner's Manual Local Area Data Set Application In this application, two pairs of wires provide the connection between two MT56DSU-R devices. The two pairs can be up to the equivalent of 3 miles of 26 AWG wire at 56000 bps, or longer for subrate applications (see distances chart in section 3.4.1 of this manual). The figure below depicts a typical Local Area Data Set application. Figure A-3.
Appendix A - Application Examples Analog Off-Net Extension Application In this application, the MT56DSU-R is used with conventional analog modems and lines to complete DDS circuits in an area where DDS is not available (Site #3 in the example below) , or where the customer requires an extension of the DDS circuit for a special application. Figure A-5. Analog Off-Net Extension Application 49 82023101.
MT56DSU-R Owner's Manual Appendix B - Interface Signals and Connector Pinouts RS232C DB9 CONNECTOR DESCRIPTION This connector ties the MT56DSU-R to the DDS Network. The DB9S connector has the following pinout configuration PIN IDENTIFICATION Pin Description Destination 1 2 3 4 5 6 7 8 9 Transmit Pair N/C Transmit Pair Receive Pair N/C N/C N/C Receive Pair N/C To Line To Line From Line From Line 50 82023101.
Appendix B - Interface Signals and Connector Pinouts RS232C DB25S CONNECTOR 13 25 12 Transmitter Signal — 24 Element Timing 23 11 10 22 9 — Test Voltage (+V) 21 8 — Carrier Detect (CD) 20 7 — Signal Ground (SG) 19 6 — Data Set Ready (DSR) 18 5 — Clear To Send (CTS) Receive Clock (RC) — 17 4 — Request To Send (RTS) 16 3 — Received Data (RD) Transmit Clock (TC) — 15 2 — Transmit Data (SD) 14 1 As viewed from the rear DESCRIPTION This connector ties the MT56DSU-R to the DTE.
MT56DSU-R Owner's Manual V.35 INTERFACE ADAPTER CABLE DESCRIPTION This adapter cable should be used when the MTDSU56-R is configured for V.35 DTE interface. You can order the V.35 Interface Adapter cable (CADSUR35) from Multi-Tech. This cable uses a 25pin male connector at one end and a 34-pin Winchester female connector at the other end. SCHEMATIC 52 82023101.
Appendix B - Interface Signals and Connector Pinouts LINE CABLE DESCRIPTION This cable lets you connect the MT56DSU-R to your DDS Network. You can order the Line cable (CA248) from Multi-Tech, or build one using the instructions below. SCHEMATIC BUILD INSTRUCTIONS 1. Strip cable insulation 3/4" . 2. Strip wires 1,3,4 and 8 on one end of cable and 1,2,7 and 8 on other end a 1/4" 3. Cut unstriped wires off. 4. Solder wire 1 on one connector to 1 on the other. 5.
MT56DSU-R Owner's Manual LOOPBACK CABLE DESCRIPTION This cable lets you test the MT56DSU-R when a second DSU is not available. It tests the DSU by having the DSU generate a signal, then the cable loops the signal back to the DSU for comparison to the original signal sent. You can order this cable (CADSURLB) from Multi-Tech, or build one using the instructions below. Refer to Chapter 4 for test procedures. SCHEMATIC BUILD INSTRUCTIONS 1. Strip cable insulation 3/4" . 2. Cut wires 2, 5, 6, 7,9 off.
Appendix B - Interface Signals and Connector Pinouts BACK-TO-BACK CABLE DESCRIPTION This cable lets you test a suspect DSU by connecting it to a known good DSU. It tests the suspect DSU by connecting its Transmit signal to the good DSUs Receive circuits. You can order it from Multi-Tech (CADSURBB), or build one using the instructions below. Refer to Chapter 4 for test procedures. SCHEMATIC BUILD INSTRUCTIONS 1. Strip cable insulation 3/4" . 3.
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MultiDSU56K TM Glossary 82023101.
MT56DSU-R Owner's Manual This section defines several of the terms used in this manual. For an overview of DSU basics, refer to section 1.8 of this manual. A ALBO (Automatic Line Build Out) - part of equalizer circuitry used to compensate for various gauges and alterations of local loops. Anti-Streaming - an option that prevents a streaming (jammed) DTE from affecting other devices on a multi-point network. Asynchronous communications - communications between computer devices at irregular intervals.
Glossary Control station - the station on a DDS multipoint circuit that is nearest the host system and transmits data to each remote station and receives a single serial bit stream from the remote stations via the MJU. Crossover cable - a cable with a conductor that runs the length of the cable, but connects to a different pin number at each end (connects pins 2 to 3 and 3 to 2 from DTE to DSU/CSU).
MT56DSU-R Owner's Manual E Elastic store - an option that causes the DSU to allow for timing phase drifts in non-DDS applications. F Four-wire circuit - two twisted-pair circuits with each pair transmitting signals in the opposite direction. J Jumper - a wire that connects two or more pins; a configurable component on a printed circuit board. L LBO (Line Build Out) - process of inserting a loss in a short transmission line to make it act like a longer line.
Glossary Multipoint circuit - a type of DDS network that includes one control station, attached remote stations, and all channel, MJU and digital access lines for station interconnection. O OCU (Office Channel unit) - a DSU/CSU located in the telco central office. OOS (Out Of Service) - a condition that occurs when a digital service failure is detected by the network.
MT56DSU-R Owner's Manual T Test pattern - a diagnostic test for sending , detecting and checking a pre-defined pattern of bits. Two-wire circuit - A circuit in which one channel (line) is used for communications in both directions. Contrast four-wire circuit. 62 82023101.
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