Multi Tech Systems Network Card MT56DSU S User Manual

MT56DSU-S  
Syncronous 56K bps  
Data Service Unit  
User Guide  
 
Contents  
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 POWERConnector ............................................................................. 12  
2.3.2 RS232Connector................................................................................ 12  
2.3.3 LINEConnector .................................................................................. 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 .................................................................................... 20  
4.1.2 Line Loopback Test ............................................................................ 21  
4.1.3 DSU Loopback Test............................................................................ 21  
4.1.4 DSU Back-to-Back Test ..................................................................... 22  
 
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) ........................ 25  
5.1.4 InternationalDistributors ..................................................................... 25  
5.2 Repairs ................................................................................................. 26  
5.2.1 Repair Procedures for U.S. and Canadian Customers ........................ 26  
5.2.2 RepairProceduresforInternationalCustomers................................... 26  
5.2.3 RepairProceduresforInternationalDistributors .................................. 27  
5.2.4 ReplacementParts ............................................................................. 27  
5.3 Technical Support ................................................................................. 27  
5.4 Internet Site .......................................................................................... 27  
Appendix............................................................................................................ 28  
AppendixA-Application Examples ................................................................ 29  
Introduction...................................................................................................... 29  
Local Area Data Set Application ...................................................................... 29  
DDSPoint-To-PointApplication ....................................................................... 29  
DDS Multipoint (Polled) Application ................................................................. 30  
Appendix B - Interface Signals and Connector Pinouts ................................. 31  
RJ-48Connector .............................................................................................. 31  
DB25SConnector ............................................................................................ 32  
DB25S Connector with V.35 Interface ............................................................. 33  
Loopback Cable (MTS P/N 45640100) ............................................................ 34  
Back-To-Back Cable (MTS P/N 45050000)..................................................... 35  
Appendix C - Regulatory Information ............................................................. 36  
FCCRegulationsforTelephoneLineInterconnection ...................................... 36  
CanadianLimitationsNotice ............................................................................ 37  
 
Chapter 1 - Introduction  
 
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  
6
 
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.  
DDS  
Network  
DSU  
DTE  
DTE  
DSU  
Figure 1-2. Basic DSU/CSU Configuration  
7
 
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 user-  
selectable 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  
8
 
Chapter 1 - Introduction  
1.6 Specifications  
Model Number:  
Device Operation:  
Data Rates:  
MT56DSU-S  
combined DSU and CSU  
Synchronous  
Interfaces:  
56 Kbps (Data port and line)  
Data (RS232)  
Data (V.35)  
Line (DDS)  
Power Requirements:  
Temperature:  
Humidity:  
DB25S (female) - Data port  
DB25S (female) - Data port with an adapter cable  
RJ-48 8-position keyed jack - Line  
115V AC, 50-60 Hz, 2 Watts  
32 to 120° F (0 to 50° C)  
20 to 90% (non-condensing)  
1" H x 4.125" W x 5.5" D  
2.5 cm H x 10.8 cm W x 14.2 cm D  
8 oz. (224 g)  
Dimensions:  
Weight:  
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)  
1.4V peak (+6dBm) into 135 Ohm at 56 Kbps  
135 ohms  
+6 to -45 dBm  
135 ohms  
Transmit Level  
OutputImpedance  
Receive Levels  
InputImpedance  
Delay Times (in secs.)  
RTS/CTS  
0.4  
DCD on  
0.3  
DCD off  
0.2  
9
 
Chapter 2 - Front & Back  
Panel Descriptions  
 
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.  
11  
 
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  
RS232  
LINE  
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.  
12  
 
Chapter 2 - Front & Back Panel Descriptions  
2.4 Switch Settings  
An 8-position DIP switch is located on the right side of the MT56DSU-S printed circuit board (when viewed  
from the front, as in Figure 2-3). The DIP switch functions are described in the following table.  
1
2
3
4
5
6
7
8
DIP-Switch  
Figure 2-3. Switch Settings  
Table 2-1. Switch Settings  
Switch  
Mode  
Position  
Description  
1
Reset  
UP*  
DOWN  
UP*  
DOWN  
UP*  
DOWN  
Normal  
Reset  
DDS  
Internal  
Normal  
Loopback  
2
Clocking  
Loopback  
Not Used  
3
4-8  
*Factory default setting  
13  
 
Chapter 2 - Front & Back Panel Descriptions  
2.5 Shunts  
V.35 signal levels are more reliable for high speed data and/or longer cable distances. For higher speeds  
and/or longer distances, V.35 is preferred. EIA-232-D signal levels are intended for data rates of 19.2 Kbps or  
less and cable lengths of 50 feet or less.  
There are two shunt positions in the middle left side of the printed circuit board that configure the data port for  
either RS232 or V.35 operation. The shunt positions are shown in Figure 2-3.  
V.35 Shunt Position  
RS232 Shunt Position  
Figure 2-3. Shunts  
The shunt position closest to the DIP switches is for RS232 data interface and the other one is for V.35 data  
interface. The shunt is shown in the RS232 (default) position in Figure 2-3. To change the position of a  
shunt, refer to the V.35 Shunt in Chapter 3.  
14  
 
Chapter 3 - Unpacking & Setup  
 
Chapter 3 - Unpacking & Setup  
3.1 Introduction  
This chapter describes the unpacking of the DSU, cable connections depending on whether EIA-232-D or  
ITU-T V.35 interface signaling is used on the data port, and how to configure the unit dependent on your site  
situation. Once the DSU is configured, then the data port can be connected to your data device.  
3.2 Unpacking  
The shipping box contains the DSU, power adapter, and a documentation CD with a User's Guide. Inspect  
the contents for signs of any shipping damage. If damage is observed, do not power up the unit, contact  
Multi-Tech's Technical Support for advice (refer to Chapter 5 - Warranty). If no damage is observed, place  
the DSU in its final location and verify the signal levels (EIA-232-D or ITU-T V.35) for the data port, and  
connect your cables, phone lines, and power supply.  
3.3 Telecom Safety Warnings  
1. Never install telephone wiring during a lightning storm.  
2. Never install telephone jacks in wet locations unless the jack is specifically designed for wet locations.  
3. This product for use with UL and cUL listed computers.  
4. Never touch uninsulated telephone wires or terminals unless the telephone line has been disconnected  
at the network interface.  
5. Use caution when installing or modifying telephone lines.  
6. Avoid using a telephone (other than a cordless type) during an electrical storm. There may be a remote  
risk of electrical shock from lightning.  
7. Do not use the telephone to report a gas leak in the vicinity of the leak.  
8. To reduce the risk of fire, use only 26AWG or larger telecommunications cord.  
16  
 
Chapter 3 - Unpacking & Setup  
3.4 Setup  
Perform the following procedure to connect your cables and, if necessary, change to V.35 signaling on the  
data port.  
1. If the DTE device has a V.35 interface, the internal shunt must be moved to the V.35 position and a V.35  
adapter cable must be connected to the data connector (labeled “RS232”). Refer to V.35 Shunt for  
procedures on moving the shunt to the V.35 position. Refer to Appendix A for cable details.  
If the DTE device has an EIA-232-D interface, a standard RS232 (straight-thru) cable can be used.  
POWER  
RS232  
LINE  
To DTE Device  
To Line Jack  
To Power Outlet  
Figure 3-1. Back Panel Connections  
2. Connect the external wall transformer power supply to the DSU, then plug the power supply into a live  
AC outlet. The DSU has no power switch; however, when power is applied to the unit, the front panel  
LEDs will light.  
3. Connect the DTE device to the RS232 connector on the back of the DSU.  
4. Connect an RJ-48 phone cable to the LINE connector on the back of the DSU. Connect the other end of  
the phone cable to the local access line jack.  
17  
 
Chapter 3 - Unpacking & Setup  
3.5 V.35 Shunt  
Either EIA-232-D or ITU-T V.35 electrical signal interface can be selected on the Data connector. Units are  
shipped with EIA-232-D signal levels selected. Use the following procedure to select V.35.  
CAUTION : This procedure requires opening the unit. Like most products of this type, this product contains  
components that are sensitive to static and static discharge. Use your best efforts to avoid static discharge  
when contacting the components inside this unit.  
WARNING: Always disconnect the power cord before opening the enclosure to avoid any chance of electric  
shock.  
1. Unplug the power cord.  
2. The enclosure consists of two halves. Using a Phillips screwdriver, remove the two screws from the  
bottom of the unit. Remove the top half.  
3. Carefully pry the shunt out of its RS232 socket and insert it into the V.35 socket.  
V.35 Shunt Position  
RS232 Shunt Position  
Figure 3-2. Shunts  
4. Carefully reassemble the unit, making sure no foreign objects are accidentally left inside.  
5. The DSU is now configured for V.35 signal levels. To connect to a device with a 34-pin Winchester  
female V.35 connector, use an adapter cable with a 25-pin female connector at one end and a 34-pin  
Winchester male connector at the other end. Using the signal pin designations in Appendix A, you can  
make or order a cable from most any cable vendor.  
18  
 
Chapter 4 - Diagnostics  
 
Chapter 4 - Diagnostics  
4.1 Introduction  
The DSU is set to a default of Normal (non-diagnostic) mode at the factory. When diagnostics are to be run,  
change the Loopback DIP switch 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. If an OOS is received when data is expected, check the remote (far-  
end) transmitting equipment. If the remote equipment is transmitting properly, contact your telephone  
company. If the Telco is required to perform remote tests, the channel will be temporarily interrupted and loss  
of data may occur.  
The following sections describe the tests that are available for the DSU.  
4.1.1 Loopback Test  
This test allows you to test the local DTE and local DSU. Use the following steps to perform the Loopback  
Test.  
1. Set DIP switch #3 to the down position.  
2. Send data from your DTE, it should be “looped back” to your DTE. If you have access to a Bit Error Rate  
Tester, this can be used in place of the DTE.  
DTE  
Local DSU  
(Or BERT Tester)  
(In Loopback Test Mode)  
Figure 4-1. Loopback Test Diagram  
20  
 
Chapter 4 - Diagnostics  
4.1.2 Line Loopback Test  
This test enables you to test the local DTE, the local DSU, the communications link, and the remote DSU. Use  
the following steps to perform the Trunk Loopback Test.  
1. Set DIP switch #3 on the remote DSU to the down position.  
2. 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.  
Network  
Local DTE  
Local DSU  
Remote DSU  
(or BERT Tester)  
(In Line Loopback Test Mode)  
Figure 4-2. Line Loopback Test Diagram  
4.1.3 DSU Loopback Test  
This test lets you verify proper DSU 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 (#45640100) from Multi-Tech, or assemble one. Refer to Appendix B for  
instructions on building the Loopback cable.  
2. Plug the Loopback cable into the back panel Line jack.  
3. Send data from your DTE, it should be “looped back” to your DTE. If you have access to a Bit Error Rate  
Tester, this can be used in place of the DTE.  
Loopback  
Cable  
DSU  
DTE  
being tested  
Figure 4-3. DSU Loopback Test  
21  
 
Chapter 4 - Diagnostics  
4.1.4 DSU Back-to-Back Test  
This test lets you connect two DSUs 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 (#45050000) from Multi-Tech, or assemble one. Refer to Appendix B  
for instructions on building the Back-to-Back cable.  
2. Plug the cable into each DSU’s Line jack.  
3. On the “good” DSU, set DIP switch #3 to the down position.  
4. Set one DSU to internal clocking and the other DSU to DDS clocking.  
5. Send data from your DTE, it should be “looped back” to your DTE. If you have access to a Bit Error Rate  
Tester, this can be used in place of the DTE.  
DTE  
“Suspect”  
DSU  
Back-to-Back  
Cable  
“Good” DSU in  
Loopback Mode  
Figure 4-4. DSU Back-to-Back Test Diagram  
22  
 
Chapter 5 - Service & Warranty  
 
Chapter 5 - Service & Warranty  
5.1 Multi-Tech Systems, Inc. Warranty & Repairs Policies  
5.1.1 Warranty  
Multi-Tech Systems, Inc., (hereafter “MTS”) warrants that its products will be free from defects in material or  
workmanship for a period of two, five, or ten years (depending on model) from date of purchase, or if proof of  
purchase is not provided, two, five, or ten years (depending on model) from date of shipment.  
MTS MAKES NO OTHER WARRANTY, EXPRESS OR IMPLIED, AND ALL IMPLIED WARRANTIES OF  
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED.  
This warranty does not apply to any products which have been damaged by lightning storms, water, or power  
surges or which have been neglected, altered, abused, used for a purpose other than the one for which they  
were manufactured, repaired by Customer or any party without MTS’s written authorization, or used in any  
manner inconsistent with MTS’s instructions.  
MTS’s entire obligation under this warranty shall be limited (at MTS’s option) to repair or replacement of any  
products which prove to be defective within the warranty period or, at MTS’s option, issuance of a refund of  
the purchase price. Defective products must be returned by Customer to MTS’s factory – transportation  
prepaid.  
MTS WILL NOT BE LIABLE FOR CONSEQUENTIAL DAMAGES, AND UNDER NO CIRCUMSTANCES WILL  
ITS LIABILITY EXCEED THE PRICE FOR DEFECTIVE PRODUCTS.  
5.1.2 U.S. and Canadian Customers  
In the event that service is required, products may be shipped, freight prepaid, to our Mounds View,  
Minnesota, factory:  
Multi-Tech Systems, Inc.  
2205 Woodale Drive  
Mounds View, MN 55112  
Attn: Repairs, Serial #______  
A Returned Materials Authorization (RMA) is not required. Return shipping charges (surface) will be paid by  
MTS. Please include inside the shipping box a description of the problem, a return shipping address (must  
have street address, not P.O. Box), a telephone number, and if the product is out of warranty, a check or  
purchase order for repair charges.  
For out of warranty repair charges, go to: www.multitech.com. Extended two-year overnight replacement  
agreements are available for selected products. Please call MTS at 888 288-5470, extension 5308, or visit  
our web site at www.multitech.com for details on rates and coverages.  
Please direct your questions regarding technical matters, product configuration, verification that the product  
is defective, etc., to our Technical Support department at 800 972-2439 or e-mail [email protected].  
Please direct your questions regarding repair expediting, receiving, shipping, billing, etc., to our Repair  
Accounting department at 800 328-9717 or +763 785-3500, or e-mail [email protected].  
Repairs for damages caused by lightning storms, water, power surges, incorrect installation, physical abuse,  
or user-caused damages are billed on a time-plus-materials basis.  
24  
 
Chapter 5 - Service & Warranty  
5.1.3 International Customers (outside U.S.A. and Canada)  
Your original point of purchase reseller may offer the quickest and most economical repair option for your  
Multi-Tech product. You may also contact any Multi-Tech sales office for information about the nearest  
distributor or other repair service for your Multi-Tech product: www.multitech.com.  
In the event that factory service is required, products may be shipped, freight prepaid, to our Mounds View,  
Minnesota, factory. Recommended international shipment methods are via Federal Express, UPS or DHL  
courier services, or by airmail parcel post; shipments made by any other method will be refused. A Returned  
Materials Authorization (RMA) is required for products shipped from outside the U.S.A. and Canada. Please  
contact us for return authorization and shipping instructions on any international shipments to the U.S.A.  
Please include inside the shipping box a description of the problem, a return shipping address (must have  
street address, not P.O. Box), your telephone number, and if the product is out of warranty, a check drawn on  
a U.S. bank or your company’s purchase order for repair charges. Repaired units will be shipped freight  
collect, unless other arrangements are made in advance.  
Please direct questions regarding technical matters, product configuration, verification that the product is  
defective, etc., to our Technical Support department nearest you, as listed at http://www.multitech.com/  
COMPANY/offices/DEFAULT.ASP., or e-mail [email protected]. When calling the U.S., please direct  
questions regarding repair expediting, receiving, shipping, billing, etc., to our Repair Accounting department  
at +763 717-5631 in the U.S.A., or e-mail [email protected].  
Repairs for damages caused by lightning storms, water, power surges, incorrect installation, physical abuse,  
or user-caused damages are billed on a time-plus-materials basis.  
5.1.4 InternationalDistributors  
Procedures for international distributors of Multi-Tech products are on the Distributor Web site at http://  
25  
 
Chapter 5 - Service & Warranty  
5.2 Repairs  
5.2.1 Repair Procedures for U.S. and Canadian Customers  
In the event that service is required, products may be shipped, freight prepaid, to our Mounds View,  
Minnesota factory:  
Multi-Tech Systems, Inc.  
2205 Woodale Drive  
Mounds View, MN 55112  
Attn: Repairs, Serial # ____________  
A Returned Materials Authorization (RMA) is not required. Return shipping charges (surface) will be paid by  
MTS. Please include, inside the shipping box, a description of the problem, a return shipping address (must  
have street address, not P.O. Box), your telephone number, and if the product is out of warranty, a check or  
Extended two-year overnight replacement service agreements are available for selected products. Please  
and coverages.  
Please direct your questions regarding technical matters, product configuration, verification that the product  
is defective, etc., to our Technical Support department at (800) 972-2439 or email [email protected].  
Please direct your questions regarding repair expediting, receiving, shipping, billing, etc., to our Repair  
Accounting department at (800) 328-9717 or (763) 717-5631, or email [email protected].  
Repairs for damages caused by lightning storms, water, power surges, incorrect installation, physical abuse,  
or user-caused damages are billed on a time-plus-materials basis.  
5.2.2 Repair Procedures for International Customers  
Your original point of purchase Reseller may offer the quickest and most economical repair option for your  
Multi-Tech product. You may also contact any Multi-Tech sales office for information about the nearest  
In the event that factory service is required, products may be shipped, freight prepaid to our Mounds View,  
Minnesota factory. Recommended international shipment methods are via Federal Express, UPS or DHL  
courier services, or by airmail parcel post; shipments made by any other method will be refused. A Returned  
Materials Authorization (RMA) is required for products shipped from outside the U.S.A. and Canada. Please  
contact us for return authorization and shipping instructions on any International shipments to the U.S.A.  
Please include, inside the shipping box, a description of the problem, a return shipping address (must have  
street address, not P.O. Box), your telephone number, and if the product is out of warranty, a check drawn on  
a U.S. bank or your company’s purchase order for repair charges. Repaired units shall be shipped freight  
collect, unless other arrangements are made in advance.  
Please direct your questions regarding technical matters, product configuration, verification that the product  
is defective, etc., to our Technical Support department nearest you or email [email protected]. When  
calling the U.S., please direct your questions regarding repair expediting, receiving, shipping, billing, etc., to  
our Repair Accounting department at: +(763) 717-5631 in the U.S.A., or email [email protected].  
26  
 
Chapter 5 - Service & Warranty  
Repairs for damages caused by lightning storms, water, power surges, incorrect installation, physical abuse,  
or user-caused damages are billed on a time-plus-materials basis.  
5.2.3 Repair Procedures for International Distributors  
Procedures for International Distributors of Multi-Tech products are on the distributor web site:  
5.2.4 Replacement Parts  
SupplyNet, Inc., can supply you with replacement power supplies, cables and connectors for selected Multi-  
Tech products. You can place an order with SupplyNet via mail, phone, fax or the Internet at the following  
addresses:  
Mail:  
SupplyNet, Inc.  
614 Corporate Way  
Valley Cottage, NY 10989  
Phone: 800 826-0279  
Fax: 914 267-2420  
5.3 Technical Support  
Multi-Tech Systems has an excellent staff of technical 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 800 972-  
2439 (USA and Canada) or 763 785-3500 (international and local). Please have modem information  
available. You can also contact Technical Support by e-mail at the following addresses:  
Country  
Email  
Telephone  
U.S.A., Canada  
France:  
India:  
U.K.:  
Rest of world:  
800 972-2439  
+(33) 1-64 61 09 81  
+91 (124) 6340778  
+(44) 118 959 7774  
+763 717-5863  
Please note the status of the modem before contacting Technical Support. Status information can include the  
state of the LED indicators, screen messages, diagnostic test results, problems with a specific application,  
etc.  
5.4 Internet Site  
Multi-Tech is a commercial provider on the Internet. Multi-Tech has a Web site at: www.multitech.com.  
27  
 
Appendix  
 
Appendix  
Appendix A - Application Examples  
Introduction  
This section illustrates several types of applications in which the MT56DSU-S is typically used. These types  
include:  
Local Area Data Set  
DDS point-to-point application  
DDS multipoint (polled) application  
Local Area Data Set Application  
In this application, two pairs of wires provide the connection between two MT56DSU-S devices. The two pairs  
can be up to the equivalent of 3 miles of AWG #26 wire at 56 Kbps, or longer for subrate applications.  
The figure below depicts a typical Local Area Data Set application.  
Up to 3 miles  
of AWG 26 wire  
@ 56 Kbps  
DSU  
DTE  
DTE  
DSU  
(Requires two pairs  
of interconnection wires)  
Figure A-1. Local Area Data Set Application  
DDS Point-To-Point Application  
In this application, the MT56DSU-S provides the interface between the DDS line and the DTE at your site.  
Your network provider will provide (at your request) a DDS line connecting the desired locations. The figure  
below depicts a sample DDS Point-to-point application.  
DDS  
Network  
DSU  
DTE  
DTE  
DSU  
Figure A-2. DDS Point-to-Point Application  
29  
 
Appendix  
DDS Multipoint (Polled) Application  
Since your Central Office (CO) equipment must include “Multipoint 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-S at the host end is the Master Station (also called the “Control Station”), which typically has  
RTS forced on. The attached MT56DSU-Ss are called “Remote stations” and have RTS controlled by the  
DTE.  
Multipoint DDS provides communication between a control station and two or more remote stations. All data  
transmitted by the control station is sent to each remote station. For data transmitted from the remote stations,  
the MJUs combine bit streams from the remote stations into a single, serial bit stream sent to the control  
station.  
The figure below shows a typical Multipoint (Polled) application.  
DSU  
(“Master Station”)  
Host with  
Database  
Application  
DDS Network  
with  
Multipoint  
Equipment  
DSU  
(“Remote Station”)  
DTE  
DSU  
(“Remote Station”)  
DTE  
DTE  
DSU  
(“Remote Station”)  
DTE  
DSU  
(“Remote Station”)  
Figure A-3. DDS Multipoint (Polled) Application  
30  
 
Appendix  
Appendix B - Interface Signals and Connector Pinouts  
RJ-48 Connector  
Pin 1  
Pin 8  
Key  
As viewed from the rear  
Figure B-1. Connector  
DESCRIPTION  
This connector ties the MT56DSU-S to the DDS Network. The RJ-48 connector is keyed for proper insertion  
of a keyed RJ-48 plug.  
PIN IDENTIFICATION  
Pin  
Description  
Destination  
1
2
3
4
5
6
7
8
Transmit Pair  
Transmit pair  
N/C  
N/C  
N/C  
N/C  
Receive Pair  
Receive Pair  
To Line  
To Line  
From Line  
From Line  
31  
 
Appendix  
DB25S Connector  
13 12 11 10  
9
8
7
6
5
4
3
2
1
25 24  
23 22  
21 20 19 18 17  
16 15 14  
Figure B-2. Connector  
DESCRIPTION  
This connector ties the MT56DSU-S to the DTE. The DB25S connector has the following pinout  
configuration.  
PIN IDENTIFICATION  
Pin  
Description  
Signal  
1
2
Chassis Ground  
Transmit Data  
SD  
3
4
5
6
7
8
Received Data  
Request To Send  
Clear To Send  
Data Set Ready  
Signal Ground  
Carrier Detect  
RD  
RTS  
CTS  
DSR  
SG  
CD  
15  
17  
20  
Transmit Clock  
Receive Clock  
Data Terminal Ready  
TC  
RC  
DTR  
32  
 
Appendix  
DB25S Connector with V.35 Interface  
13 12 11 10  
9
8
7
6
5
4
3
2
1
25 24  
23 22  
21 20 19 18 17  
16 15 14  
Figure B-3. Connector  
DESCRIPTION  
The DB25 connector also ties the MT56DSU-S to a DTE with a V.35 interface. When a V.35 interface device  
is connected to a MT56DSU-S, the internal shunt has to be moved to the V.35 position. The V.35 interface for  
the DB25 connector has the following pinout configuration.  
PIN IDENTIFICATION  
Pin  
Description  
1
7
4
5
6
8
Chassis Ground  
Signal Ground  
Request To Send  
Clear To Send  
Data Set Ready  
Carrier Detect  
20  
2
12  
3
22  
15  
21  
17  
18  
Data Terminal Ready  
Transmit Data (A)  
Transmit Data (B)  
Receive Data (A)  
Receive Data (B)  
Transmit Clock (A)  
Transmit Clock (B)  
Receive Clock (A)  
Receive Clock (B)  
33  
 
Appendix  
Loopback Cable (MTS P/N 45640100)  
1
8
Figure B-5. Loopback Cable Connector  
DESCRIPTION  
This cable lets you test the MT56DSU-S when a second DSU is not available. When the DSU generates a  
signal, this cable “loops” the signal back to the DSU for comparison to the original signal sent. You can  
order this cable (#45640100) from Multi-Tech, or build one using the instructions below. Refer to Chapter 4  
for test procedures.  
SCHEMATIC  
TRANSMIT  
1
TRANSMIT  
2
3
4
5
RJ48S  
6
7
RECEIVE  
RECEIVE  
8
6"  
Figure B-6.  
BUILD INSTRUCTIONS  
1. Strip cable insulation 3/4"  
2. Cut wires 3, 4, 5, 6 off.  
3. Strip wires 1, 2, 7, 8 1/4"  
4. Solder wires 1 and 8 together.  
5. Solder wires 2 and 7 together.  
6. Cover solder connections with 1" of shrink tube.  
34  
 
Appendix  
Back-To-Back Cable (MTS P/N 45050000)  
1
8
Figure B-7. Back-toBack Cable Connector  
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 Receive circuits of the good DSU. You can order this cable from Multi-  
Tech (#45050000), or build one using the instructions below. Refer to Chapter 4 for test procedures.  
SCHEMATIC  
8
7
6
5
4
3
2
1
1
2
3
4
5
6
7
8
RJ48S  
RJ48S  
7"  
Figure B-8.  
BUILD INSTRUCTIONS  
1. Strip cable installation 3/4".  
2. Strip wires 1,2,7 and 8 on one end of cable and 8,7,2 and 1 on other end 1/4".  
3. Cut unstripped wires off.  
4. Solder wire 1 on one connector to 8 on the other.  
5. Solder wire 2 on one connector to 7 on the other.  
6. Solder wire 7 on one connector to 2 on the other.  
7. Solder wire 8 on one connector to 1 on the other.  
8. Cover solder connections with 1" of shrink tube.  
35  
 
Appendix  
Appendix C - Regulatory Information  
FCC Regulations for Telephone Line Interconnection  
1. This equipment complies with Part 68 of the FCC rules. On the outside surface of this equipment 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 below, the suitable jack (USOC) connecting arrangement for this equipment is shown in  
Appendix B. If applicable, the facility interface codes (FIC) and service order codes (SOC) are also  
indicated.  
3. The ringer equivalence number (REN) is used to determine the quantity of devices which may be  
connected to the telephone line. Excessive REN’s on the telephone line may result in the devices not  
ringing in response to an incoming call. In most, but not all areas, the sum of the REN’s should not  
exceed five (5.0). To be certain of the number of devices that may be connected to the line, as  
determined by the total REN’s, contact the telephone company to determine the maximum REN for the  
calling area.  
4. If this equipment causes harm to the telephone network, the telephone company will notify you in  
advance. But if advance notice isn’t practical, the telephone company will notify the customer as soon as  
possible. Also, you will be advised of your right to file a complaint with the FCC if you believe it is  
necessary.  
5. The telephone company may make changes in its facilities, equipment, operations, or procedures that  
could affect the operation of the equipment. If this happens, the telephone company will provide advance  
notice in order for you to make necessary modifications in order to maintain uninterrupted service.  
6. If trouble is experienced with this equipment (the model of which is indicated below) please contact  
Multi-Tech Systems, Inc. at the address shown below for details of how to have repairs made. If the  
trouble is causing harm to the telephone network, the telephone company may request you remove the  
equipment from the network until the problem is resolved.  
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.)  
Manufacturer:  
Multi-Tech Systems, Inc.  
Model Number:  
MT56DSU-S  
FCC Pt 68 Registration #:  
Ringer Equivalence:  
SOC Codes:  
AU7USA-24704-XD-N  
N/A  
6.0N  
Modular jack (USOC):  
Service Center in U.S.A.:  
RJ-48S  
Multi-Tech Systems, Inc.  
2205 Woodale Drive  
Mounds View, MN 55112 USA  
(763) 785-3500 or (800) 328-9717  
U.S. Fax (763) 785-9874  
36  
 
Appendix  
Canadian Limitations Notice  
Notice: The ringer equivalence number (REN) assigned to each terminal device provides an indication of the  
maximum number of terminals allowed to be connected to a telephone interface. The termination of a  
interface may consist of any combination of devices subject only to the requirement that the sum of the ringer  
equivalence numbers of all the devices does not exceed 5.  
Notice: The Industry Canada label identifies certificated equipment. This certification means that the  
equipment meets certain telecommunications network protective, operational and safety requirements. The  
Industry Canada does not guarantee the equipment will operate to the user’s satisfaction.  
Before installing this equipment, users should ensure that it is permissible to be connected to the facilities of  
the local telecommunications company. The equipment must also be installed using an acceptable method of  
connection. The customer should be aware that compliance with the above conditions may not prevent  
degradation of service in some situations.  
Repairs to certified equipment should be made by an authorized Canadian maintenance facility designated  
by the supplier. Any repairs or alterations made by the user to this equipment, or equipment malfunctions,  
may give the telecommunications company cause to request the user to disconnect the equipment.  
Users should ensure for their own protection that the electrical ground connections of the power utility,  
telephone lines and internal metallic water pipe system, if present, are connected together. This precaution  
may be particularly important in rural areas.  
Caution: Users should not attempt to make such connections themselves, but should contact the appropriate  
electric inspection authority, or electrician, as appropriate.  
37  
 
S000327A  
 

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