3Com Network Card 980 000048 001 User Manual

ACCESSBUILDER 7000  
TRIPLE MODEM MODULE  
USER GUIDE  
®
Part No. 980/000048/001  
Published June 1996  
 
IMPORTANT SAFETY INFORMATION  
WARNING: Warnings contain directions that you must follow for your  
personal safety. Follow all instructions carefully.  
Please read carefully and thoroughly the following information before  
installing the AccessBuilder 7000 Triple Modem Module:  
Exceptional care must be taken during installation and removal of the  
module.  
The safety status of the interconnection ports on this equipment are as  
follows:  
Ports identified by the label PSTN and LEASE = TNV  
Ports identified by the labels DTE = SELV  
TNV (telecoms network voltage) is a circuit which under normal  
operating conditions carries telecommunication signals.  
SELV (safety extra low voltage) is a secondary circuit which is designed  
and protected so that under normal and single-fault conditions, the  
voltage between any two accessible parts does not exceed a safe value  
(42.2 V peak or 60 V DC).  
Only connect apparatus complying with the relevant interface  
requirements to the ports on this unit.  
 
 
WICHTIGE SICHERHEITSHINWEISE  
ACHTUNG: Die Warnungen enthalten Anweisungen, die Sie zur  
eigenen Sicherheit zu befolgen haben.  
Lesen Sie bitte die folgenden Informationen sorgfältig durch, bevor Sie  
den AccessBuilder 7000 Triple Modem Module einbauen:  
Auf besondere Vorsicht muß während des Ein- und Ausbaus des  
Einheits geachtet werden.  
Der Sicherheitsstandard der Anschlüsse fuer dieses Gerät sind wie folgt:  
Anschlüsse bezeichnet mit PSTN und LEASE = TNV  
Anschlüsse bezeichnet mit DTE = SELV  
TNV (Telecoms Network Voltage - Spannung des  
Telekommunikationsnetzwerks) ist ein Anschluss, der unter normalen  
Umständen Telekommunikationssignale enthält .  
SELV (Safety Extra Low Voltage - Extra Sicherheitsspannung) ist ein  
weiterer Anschluss, der unter normalen Umständen und  
Fehlerkonditionen entworfen und gesichert wurde, so dass die  
Spannung zwischen zwei erreichbaren Teilen kein gefährliches Niveau  
erreicht (42.2V max. oder 60V DC).  
An den Anschlussbuchsen der Geräte dürfen nur die dafür  
vorgesehenen Anschlüsse verwendet werden.  
 
 
L’INFORMATION DE SÉCURITÉ  
IMPORTANTE  
AVERTISSEMENT: Les avertissements contiennent les instructions que  
vous devez suivre pour votre sécurité personnelle. Suivre toutes les  
instructions avec soin.  
Veuillez lire à fond l’information suivante avant d’installer le moyeu:  
Le soin exceptionnel doit être pris pendant l’installation et l’enlèvement  
du moyeu.  
Les normes de sécurité des ports d'interconnexion sur cet équipement  
sont les suivants:  
Les ports marqués par les etiquettes PSTN et LEASE = TNV  
Les ports marqués par les etiquettes DTE = SELV  
TNV (Telecoms Network Voltage - tension réseau de  
télécommunications) est un circuit qui dans des conditions  
d'opérations normales, transfert les signeaux télécoms.  
SELV (Safety Extra Low Voltage - tension de sécurité extra-réduite) est  
un circuit secondaire désigné et protègé qui dans des conditions  
normales et de fautes uniques, assure que la tension entre deux  
éléments accessibles n'accedéra pas un niveau de sécurité (42.2V max.  
ou 60 V DC).  
Connecter uniquement des unités conformes aux normes relatives des  
interfaces de cet équipement.  
 
 
 
CONTENTS  
IMPORTANT SAFETY INFORMATION  
WICHTIGE SICHERHEITSHINWEISE  
ABOUT THIS GUIDE  
Introduction  
How to Use This Guide  
Conventions  
Additional Safety Information  
1
2
1 TRIPLE MODEM MODULE  
Introduction 1-1  
Principal Features 1-2  
Pack Contents Checklist 1-6  
Pre-installation Requirements 1-7  
2 INSTALLATION AND OPERATION  
Overview 2-1  
Installing The Module 2-2  
Installing the Rear Card 2-3  
Installing the Front Card 2-4  
Connecting the Cables 2-5  
Modem Lines 1-3 2-5  
DTE Ports 1- 3 2-5  
Front Panel LEDs 2-6  
 
3 TROUBLESHOOTING  
Troubleshooting Guide 3-1  
Modem Health 3-1  
Modem - DTE Connection 3-2  
Modem - Telephone Line Connection 3-3  
On-line Operation 3-6  
Private-line Operation 3-6  
A MODEM SPECIFICATION AND INTERFACE PIN  
ASSIGNMENTS  
Transmitter / Receiver Specifications A-1  
Autodial - Autoanswer A-2  
Physical Description A-3  
Approvals Information A-4  
Interference and Safety Requirements A-5  
PBX and PABX Application A-6  
Ringer Equivalence A-7  
DTE Port Pin Assignments A-8  
X.21/V.11 A-8  
V.24/V.28 A-9  
V.35/V.36 A-10  
PSTN Port Cable Pin Assignments A-11  
Private Line Port Cable Pin Assignments A-12  
 
B TECHNICAL SUPPORT  
On-line Technical Services D-1  
3Com Bulletin Board Service D-1  
Access by Modem D-1  
Access by ISDN D-2  
World Wide Web Site D-2  
Support from 3Com D-4  
Returning Products for Repair D-5  
INDEX  
LIMITED WARRANTY  
FCC CLASS A VERIFICATION STATEMENT  
 
 
ABOUT THIS GUIDE  
Introduction  
This guide describes the features, installation and configuration of the  
AccessBuilder 7000 Triple Modem Module.  
This guide assumes that you have installed your AccessBuilder 7000  
Access Concentrator and that the phone lines to which you want to  
connect the modems are installed and operational.  
How to Use This Guide  
This table shows where to find specific information:  
If you are looking for information on:  
Turn to:  
The Triple Modem Module’s features and typical  
uses.  
Chapter 1  
Installation and descriptions of the front panel  
LEDs and rear panel connectors.  
Chapter 2  
Troubleshooting and problem solving.  
Technical information and cable specifications.  
ASCII character table.  
Chapter 3  
Appendix A  
Appendix B  
Appendix C  
Appendix D  
Regulatory information.  
Technical support.  
 
     
2
ABOUT THIS GUIDE  
Conventions  
The icon conventions that are used throughout this guide are:  
Icon  
Type  
Description  
Information Note  
Information notes call attention to  
important features or instructions.  
Caution  
Warning  
Cautions alert you to personal safety  
risk, system damage, or loss of data.  
Warnings alert you to the risk of  
severe personal injury.  
The text conventions used in this guide are:  
Convention  
Description  
“Enter” vs. “Type”  
When the word “enter” is used in this guide,  
it means type something, then press the  
[Return] or [Enter] key. Do not press the  
[Return] or [Enter] key when an instruction  
simply says “type.”  
Text represented as  
This typefaceis used to represent  
screen display displays on your screen, for example:  
Enter the unit’s IP address:  
Text represented as  
This typeface is used to represent  
commands  
commands that you enter, for example:  
CO IS NU  
Keys  
When specific keys are referred to in the  
text, they are called out by their labels, such  
as “the Return key” or “the Escape key,” or  
they may be shown as [Return] or [Esc].  
If two or more keys are to be pressed  
simultaneously, the keys are linked with a  
plus sign (+), for example:  
Press [Ctrl]+[Alt]+[Del].  
Italics  
Italics are used to denote new terms or  
emphasis.  
 
 
Additional Safety Information  
3
Additional Safety Information  
See also the Important Safety Information at the front of this guide.  
When using the unit, observe the following safety information:  
Retain this user’s guide for later use and pass it on in the event of  
change of ownership of the unit.  
Products manufactured by us are safe and without risk provided they  
are installed, used and maintained in good working order in  
accordance with our instructions and recommendations.  
If any of the following conditions occur, isolate the electricity supply  
and refer to your 3Com reseller.  
If the module is damaged.  
If the module begins to make an odd noise, smell or smoke.  
If the module shows signs of a distinct change in performance.  
Never install telephone wires during a lightening storm, or install  
telephone connection sockets in wet locations, unless the socket is  
specifically designed for wet locations.  
Do not touch uninstalled telephone wires or terminals unless the  
telephone line has been disconnected at the network interface. Always  
exercise caution when installing or modifying telephone lines.  
Do not spill food or liquids on the unit. If the unit gets wet, isolate the  
electrical supply and contact your 3Com reseller.  
Do not push any objects into the openings of the unit. Doing so can  
cause fire or electric shock by shorting out internal components.  
Be sure nothing rests on the unit’s system cables and that the cables are  
not located where they can be stepped on and cause damage to the unit.  
Keep the unit away from radiators and heat sources.  
Install the unit in a clean area free from dust or extreme temperatures.  
Interconnecting directly, or by way of other apparatus, to ports  
complying with SELV requirements may produce hazardous conditions  
on the network. Advice should be sought from a competent engineer  
before such a connection is made.  
 
 
4
ABOUT THIS GUIDE  
 
TRIPLE MODEM MODULE  
1
Introduction  
This chapter outlines the features and uses of the AccessBuilder 7000  
Triple Modem Module when installed in the AccessBuilder 7000 Access  
Concentrator chassis.  
The Triple Modem Module houses three modems on a single device  
module that operate independently of each other but are identical in  
the features and facilities they offer. Each modem is a fully featured,  
high speed device which provides reliable asynchronous and  
synchronous operation over dialled or private line networks.  
The high speed transfer of up to 33.6 Kbps over dialled lines is  
guaranteed by using CCITT V.42bis/MNP Class 5 data compression and  
CCITT V.42/MNP error correction. IN addition to the fast line speeds,  
each modem can transfer data to the attached computer at speeds  
which can vary from 300 bps to 115200 bps.  
The modems are compatible with a number of dialling methods and  
protocols, such as asynchronous AT commands and CCITT V.25bis  
dialling, which allow you to uses the modems in a variety of  
applications and environments. You can control each Triple Modem’s  
configuration, dialling characteristics and diagnostic features. Five  
factory set configurations, containing the most commonly-used Triple  
Modem settings, are permanently stored in each Triple Modem’s  
memory, providing a quick and easy method of a configuring a Triple  
Modem to be compatible with asynchronous and synchronous data  
environments over 2-wire or 4-wire Private lines or the PSTN.  
 
       
1-2  
CHAPTER 1: TRIPLE MODEM MODULE  
Principal Features  
Support for dial-up transmission protocols:  
V.34 – 2-wire full duplex modems operating at data signalling rates  
of 33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800, 14400,  
12000, 9600, 7200, 4800 and 2400 bps.  
Non-proprietary V.32 terbo – 2-wire full duplex modems operating  
at data signalling rates of 19200, 16800, 14400, 12000, 9600, 7200  
and 4800 bps.  
V.32bis – 2-wire full duplex modems operating at data signalling  
rates of 14400, 12000, 9600, 7200 and 4800 bps.  
V.32 – 2-wire full duplex modems operating at data signalling rates  
of 9600 and 4800 bps.  
V.23 – 75/1200 bps operation.  
V.22bis – 2400 bps full duplex operation.  
V.22 and Bell 212A – 1200 bps full duplex 2-wire modem.  
V.21 and Bell 103J – 300 bps modems.  
Support for leased line transmission protocols:  
V.34 – 2-wire or 4-wire full duplex modems operating at data  
signalling rates of 33600, 31200, 28800, 26400, 24000, 21600, 19200,  
16800, 14400, 12000, 9600, 7200, 4800 and 2400 bps.  
Non-proprietary V.32 terbo – 2-wire or 4-wire full duplex modems  
operating at data signalling rates of 19200, 16800, 14400, 12000,  
9600, 7200 and 4800 bps.  
V.32bis – 2-wire or 4-wire full duplex modems operating at data  
signalling rates of 14400, 12000, 9600, 7200 and 4800 bps.  
V.32 – 2-wire or 4-wire full duplex modems operating at data  
signalling rates of 9600 and 4800 bps.  
2-wire PSTN backup of the Private line.  
CCITT V.42bis or MNP Class 5 data compression.  
Virtual error-free data passage using CCITT V.42 LAPM or MNP Level 4  
error correction.  
 
   
Introduction  
1-3  
Asynchronous dial DTE data rates from 300 to 115200 bps.  
Modem configuration changes using the DTE interface or throught the  
Management Controller Module.  
Compatibility with the industry standard AT command set.  
Storage of up to 20 telephone numbers in directory locations.  
Dialling using AT commands, CCITT V.25bis commands or by raising  
DTR on the Host to modem interface, or by data being sent to the DTE  
interface.  
High-speed transmission using asynchronous or synchronous, or UNIX  
devices over full duplex dial networks, and 2-wire or 4-wire lines.  
Self testing facilities providing local and remote loopbacks, including  
CCITT-compatible V.54.  
Five factory-set configurations and two user definable configurations.  
Front panel LEDs to inform you of the current status of any of the three  
modems.  
Easy to install, configure and support.  
Implementation of V.32terbo  
Support of the V.32terbo transmission protocol is included as a feature in  
the modems. V.32terbo is a non-proprietary extension of the widely used  
CCITT V.32bis standard which increases the maximum data signalling rate  
from 14400 to 19200 bps over dial-up links or private lines.  
Compatibility between V.32terbo and V.32bis is maintained in a similar  
manner as it is between V.32bis and V.32, in that an identical training  
sequence is used by each standard and that V.32terbo uses a subset of  
the speeds available in V.32bis.  
By default, each modem’s factory configurations enable V.32terbo to be  
negotiated as the optimum data rate on any given link allowing a 33%  
increase in line throughput, to 19200bps to be used wherever possible.  
Where the quality of the line is not good enough to enable  
transmission at 19200bps, an intermediate speed of 16800 bps can be  
 
   
1-4  
CHAPTER 1: TRIPLE MODEM MODULE  
negotiated between modems, providing a 16.7% increase in speed  
over that which can be negotiated using V.32bis. If the modem you are  
calling is unable to operate at the same high speeds as your modem,  
an optimum data transfer rate is negotiated between the two using the  
default configuration settings.  
When using the higher line speeds made available by V.32terbo, the  
throughput rate can be increased further by using the modem’s error  
correction and data compression facilities. Compression factors remain  
virtually unaffected by the increase in line rate, thereby producing a real  
improvement in data transmission times over those achieved using V.32bis.  
 
Introduction  
1-5  
Typical Applications  
The Triple Modem module is ideally suited for large central sites providing  
access for remote users to central site services. In the example shown in  
Figure 1-1 a large number of remote users connect to the central site’s  
AccessBuilder 7000 and gain access to the corporate LAN and its facilities  
through a terminal server (such as the 3Com CS3000/3100 series). The  
advantage of this method is that all devices on the corporate LAN can be  
accessed remotely by a large number of remote users.  
Figure 1-1 Modem Connections To The Central Site.  
 
     
1-6  
CHAPTER 1: TRIPLE MODEM MODULE  
Pack Contents Checklist  
Before you install your Triple Modem Module, check the contents of  
the box against the pack contents checklist below. If any of the items  
have been damaged in transit or are missing, then contact the 3Com  
reseller from whom the equipment was purchased.  
1 x Triple Modem Module front card.  
1 x Triple Modem Module back card.  
1 x AccessBuilder 7000 Triple Modem Module User Guide (This manual).  
1 x AccessBuilder AT Command Reference guide.  
1 x warranty registration card.  
It is important that you save the box and protective packing material in  
case you need to store, or transport your Triple Modem Module in the  
future.  
Registering Ownership of your Triple Modem Module  
A warranty registration card is enclosed in the box with your  
AccessBuilder 7000 Triple Modem Module. Please take a few moments  
before commencing the installation to fill in the card and post it to us.  
 
     
Pre-installation Requirements  
1-7  
Pre-installation Requirements  
Before you install the Triple Modem Module into the AccessBuilder 7000  
Access Concentrator chassis, check that the following requirements have  
been met:  
The AccessBuilder 7000 Access Concentrator must already be fitted  
with its power supply module(s) and the Management Controller  
Module if required.  
The rack unit into which you install the AccessBuilder 7000 must allow  
for the door to be fully opened to remove existing modules or to install  
new modules. During normal operation the door must remain closed.  
You should have DTE and telephone connection cables available and  
have easy access to telephone connection points.  
If you are using a terminal server for connection to your LAN, check  
that this is installed and configured for operation.  
 
   
1-8  
CHAPTER 1: TRIPLE MODEM MODULE  
 
INSTALLATION AND OPERATION  
2
Overview  
This chapter describes how to install the AccessBuilder 7000 Triple  
Modem module into the AccessBuilder 7000 Access Concentrator  
chassis, how to connect to your DTEs and PSTN lines and how to read  
the LEDs on the module’s front panel.  
Ensure you read the safety information at the front of this guide before  
commencing installation of the AccessBuilder 7000 Triple Modem Module.  
Check that you have met all the pre-requisites out-lined in Chapter 1  
and that you have access to the phone lines to connect your modems.  
 
     
2-2  
CHAPTER 2: INSTALLATION AND OPERATION  
Installing The Module  
Before installing the module, read the Safety Information at the front of  
this guide.  
An AccessBuilder 7000 module consists of two parts; a front card and a  
back card that both connect to the chassis’ backplane. It is recommended  
that you install the module’s rear card into the chassis first.  
The installation of the Triple Modem Module into the AccessBuilder  
7000 chassis takes place in three distinct operations:  
Installing the front card.  
Installing the rear card.  
Connecting cables to the DTE and Line ports. See “Connecting the  
Cables” on page 2-5 for more information about connecting to the ports.  
Modules within the AccessBuilder 7000 system are designed to be hot  
swapable. It is not necessary to turn off the AccessBuilder 7000’s power  
supply unit to install the Triple Modem Module. The Triple Modem  
Module can be inserted any slot in the AccessBuilder 7000 chassis.  
No connecting cables are supplied with the Triple Modem Module as  
standard. For each of the three modems you need a PSTN line cable  
and/or a 2/4-wire private line cable. You also need a cable to connect  
your computer or DTE equipment to the DTE interface on the modem.  
The male DTE connector conforms to the electrical characteristics of  
V.24 as described in Appendix A.  
CAUTION: At all times, take care not to touch any of the connectors or  
components on the cards to avoid damage by static electricity. Handle  
the cards by the handles or by their edges. Use an anti-static wrist strap  
during installation if you have one available.  
 
   
Installing The Module  
2-3  
Installing the Rear Card  
Figure 2-1 Installing The Rear Card  
1
2
Locate the rear slot equivalent to the front slot into which you will  
install the front card.  
Remove the metal blanking plate at the rear of the chassis and retain  
the screws.  
Retain the blanking plate. If you remove the module, the blanking plate  
must be refitted to the chassis to aid the circulation of cooling air and  
to prevent dust and debris entering the unit.  
3
4
Insert the rear card with the RJ45 ports at the top of the card and slide  
it home along the guide rails so that it connects with the backplane.  
Secure the rear card into position using the screws from the blanking plate.  
 
   
2-4  
CHAPTER 2: INSTALLATION AND OPERATION  
Installing the Front Card  
Figure 2-2 Example of Installing A Front Card  
1
2
3
4
Locate the front slot in the AccessBuilder 7000 chassis equivalent to the  
rear slot in which you have already installed the rear card.  
Insert the front card into the slot ensuring that it is centered along the  
guide rails.  
Use the module’s handles to push the card home into the chassis and  
lock it into place.  
Close and lock the chassis door.  
To remove the card, unlatch the handles to free the card from the back  
plane and pull the front card free from the chassis using the handles.  
 
   
Installing The Module  
2-5  
Connecting the Cables  
The ports on the rear panel are arranged in two groups.  
Modem Lines 1-3  
Each modem port has two connections:  
1
2
3
Dial Line (1, 3 & 5) The upper RJ45 connection in each pair  
connects to a normal dialled service, use this port to  
connect your modem to the line. In some countries you may  
need to use an adapter to connect to your PSTN service  
provider’s socket.  
4
5
6
If you use a two into one line adapter, a telephone  
handset can be connected in parallel to your modem at  
the PSTN outlet. In this case you must not lift the  
telephone handset during data transmission. If it is lifted,  
any noise in the surrounding area interferes with the data  
and can cause corruption in the transferred data.  
7
Private Line (2,4 & 6) The lower RJ45 connection in each  
pair connects to a private line. Use this port to connect  
your modem to the line. In some countries you may need  
to use an adapter to connect to your PSTN service  
provider’s socket.  
8
9
DTE Ports 1- 3 (7,8 & 9)  
Connect DTEs 1 through 3 to these ports using V.24  
modem cable as described in Appendix A.  
The DTE ports also allow direct access to the Triple Modem  
Module’s management system using a PC or terminal. This  
removes the need to access the Triple Modem Module  
through the AccessBuilder 7000 Management Controller  
Module.  
For more information about configuring the module, see  
the AccessBuilder 7000 AT Command Reference.  
 
       
2-6  
CHAPTER 2: INSTALLATION AND OPERATION  
Front Panel LEDs  
This section describes the Triple Modem Module’s LEDs. Most of the LEDs  
can only be seen when the front door of the AccessBuilder 7000 chassis is  
open. When the door is closed, only the PWR, ALARM, ALERT and TEST  
LEDs can be seen. These LEDs show the status of the whole module.  
The other status LEDs show information about one modem only. You can  
select the modem by toggling the push button at the foot of the module.  
ANS (Answer) Lights to show that the selected modem is configured to  
automatically answer an incoming PSTN call. When an incoming call is  
detected, this LED flashes in sequence with each ring pulse.  
TERM (Terminal) Shows that a DTE is attached to the selected  
modem’s DTE interface and that DTR is raised. It is normally used to  
indicate that a call can be made or an incoming a call answered. The  
modem may be configured to act in different ways on receipt of this  
signal according to the AT&Dand AT&Mcommands. See AccessBuilder  
7000 AT Command Reference for more information.  
LINE (On Line) Indicates that the selected modem has seized the  
telephone line.  
CONN (Connect) Indicates that the selected modem has established a  
valid connection to the remote device and is either negotiating the  
error correction and data compression protocols to be used on the link  
or it is ready to send and receive data. This LED does not indicate that  
the DCD (Data Carrier Detect) signal is high on the DTE interface.  
CORR (Correct) Indicates that an error correcting link has been made with  
the remote modem. While using this facility, each time a re-send request is  
initiated by the selected modem the LED flashes for a short period.  
COMP (Compress) Indicates that the data compression facility is active  
on the selected modem’s link giving you the maximum throughput  
speed. During a call, this LED may go out when the modem is using  
V.42bis compression if the modem determines that the link cannot  
benefit from compression.  
 
               
Front Panel LEDs  
2-7  
PWR (Power) When lit indicates that the module is receiving power from  
the chassis’ backplane and that the power circuits are functioning correctly.  
ALARM Lights to indicate that an event has occurred on one or more  
of the modems which has been configured to raise an alarm. See the  
AccessBuilder 7000 Access Concentrator User Guide for more information.  
ALERT Lights to indicate that an event has occurred on one or more of  
the modems which has been configured to raise an alert. See the  
AccessBuilder 7000 Access Concentrator User Guide for more information.  
TEST Indicates that one of the modems on the module is running a  
test. This may have been initiated either by an attached DTE, via the  
Management Controller Module or by a remote DTE to which the  
modem has a communications link.  
SEND Flashes on and off to indicate that the selected modem is  
receiving data from the equipment attached to the DTE interface.  
REC (Receive) Flashes on and off to indicate that the selected modem  
is passing received data from the line to the DTE interface.  
CH 1 (Modem 1) Shows that Modem 1 is selected and that the LEDs show  
the status of this modem.  
CH 2 (Modem 2 Shows that Modem 2 is selected and that the LEDs show  
the status of this modem.  
CH 3 (Modem 3) Shows that Modem 3 is selected and that the LEDs show  
the status of this modem.  
Push Button Selects the modem whose status is shown by the front  
panel LEDs. Toggle this button until the required Modem LED is lit.  
 
                   
2-8  
CHAPTER 2: INSTALLATION AND OPERATION  
 
TROUBLESHOOTING  
3
Troubleshooting Guide  
In this section we discuss the basic problems that can occur when using  
your modem. If you are having data communication difficulties such as  
periodic character loss, random errors, or constant format errors: use the  
loopback tests described in AccessBuilder 7000 AT Command Reference.  
With these tests you can usually isolate the fault in your system by using  
a process of elimination. If a problem continues to occur, contact your  
supplier for assistance.  
Modem Health  
POWER LED does not light  
Make sure that the front and rear cards are pushed fully home, and that  
the rack enclosure is powered ON.  
A problem is suspected after the power-up self-test  
Initiate a local analogue loopback with a pattern test. If the modem  
consistently registers errors, contact your modem supplier.  
If the modem passes these tests and you still have a problem, it is  
probably not with your modem.  
 
         
3-2  
CHAPTER 3: TROUBLESHOOTING  
Modem - DTE Connection  
Modem does not accept or echo back AT commands  
Check that the cable between the serial port of the DTE and the modem  
is a standard RS232 cable. If the cable is bad, replace it. (Null modem  
cables, also known as cross-over cables, do not work in this application).  
A limited number of dumb terminals require DCD before they can talk  
to the modem. If this is the case you have to use a breakout box to  
raise DCD to the terminal. You can then configure the modems to force  
DCD using the AT&C0command.  
Check that the character echo command is enabled using the ATE  
command.  
Check that the DTE dialler type configuration option is set to AT. Refer  
to the AT&Mor AT&Qcommand description.  
Check that the response codes configuration option is enabled using  
the ATQcommand.  
Make sure that all AT commands are terminated with a carriage return.  
Check that the ASCII value of a carriage return matches what is used by  
the DTE and the modem (defined using S-Register S3).  
Check that the DTE and modem are using a compatible character format.  
Valid formats include 8 data bits with no parity, or 7 data bits with even,  
odd, mark or space parity.  
Check that the DTE’s data rate is supported by the modem.  
 
 
Troubleshooting Guide  
3-3  
Modem - Telephone Line Connection  
Connection Problems in Answering a Call  
Modem does not receive a dial tone  
Attach a telephone direct to the wall outlet to check if a dial tone exists.  
Make sure the telephone line is connected to the appropriate modem’s  
rear panel PSTN jack.  
Modem does not go off-hook and answer an incoming call  
Check that the auto-answer ring count configuration option  
(S-Register 0) is set to a value other than 0.  
Check that the DTE is providing DTR to the modem.  
If the DTE does not provide DTR to the modem, check that the modem’s  
DTR signalling configuration option is set to ignore the state of DTR.  
Check that all cables are attached to the right connectors at the rear of  
the modem.  
Modem goes off-hook, answers, but does not connect  
Perform a local analogue loop test and check that data entered at the  
DTE is echoed back to the DTE.  
Check that the originating modem’s configuration is compatible with  
your receiving modem’s configuration.  
Check that the originating modem recognizes your modem’s answer tone.  
Check that the originating modem supports your modem’s operating  
protocols.  
Force your modem to operate using the same transmission protocol as  
the originating modem to see if they connect.  
 
   
3-4  
CHAPTER 3: TROUBLESHOOTING  
Connection Problems When Originating a Call  
Modem fails to go off-hook and originate a call  
Check that the modem’s configuration enables either AT dialling or  
V.25bis dialling. Note: A modem configured to accept AT commands  
cannot accept V.25bis commands, and vice versa.  
If using DTR dialling, check the telephone number stored in directory  
location 1, and check that the DTE is raising DTR from OFF to ON to  
initiate a dial.  
If using V.25bis asynchronous dialling, check that the correct character  
format is set to 7 data bits with even parity and 1 stop bit, and the  
carriage return and line feed are used as command terminators.  
If using V.25bis bisynchronous dialling, check that the correct character  
format uses two synchronous control characters and a start-of-text  
control character before the text block, and an end-of-text control  
character after it.  
If using V.25bis HDLC, check that the correct character format uses flag,  
address and control characters before the text block, and a frame  
sequence check and flag after the text block.  
Modem dials but does not connect  
If the modem is operating behind a PBX, check if a 9 and comma are  
needed before the telephone number.  
Check whether tone or pulse dialling is needed.  
Check if one modem is configured for error correction or disconnect,  
and the other modem is configured for no error correction. Try  
initiating the call in buffer mode.  
If both modems use V.32bis or V.32, set the modem’s V.32bis training  
configuration option to Long.  
 
 
Troubleshooting Guide  
3-5  
Intermittent disconnects, high error rates, or excessive  
retransmissions  
Perform a remote digital loop test as described in the AccessBuilder  
7000 AT Command Reference.  
Modem establishes and disconnects a call  
You may have a poor telephone line connection. Disconnect and dial  
again.  
The remote modem may have encountered an error correction  
disconnect, where the modem is configured to establish a call using error  
correction. If the modem cannot negotiate error correction, then a  
disconnect occurs.  
The remote modem may be in a forced error correction mode  
(disconnect if there is no error control). Reconfigure your modem to  
V.42/MNP or buffer correction and try again.  
Perform a local analogue loop test.  
 
3-6  
CHAPTER 3: TROUBLESHOOTING  
On-line Operation  
Data is scrambled  
Check that the character format (data bits, parity, and stop bits) is set to  
the same value in both modems.  
Missing data during a transfer  
Check that you are using the same method of flow control for both the  
modem and the DTE.  
If using XON/XOFF flow control, check that the modem’s parity matches  
the DTE’s parity.  
Private-line Operation  
Modems do not train-up on private lines  
Check that the correct cabling is used for your application.  
Check that one modem is configured for answer mode and the other is  
configured for originate mode.  
Check that both modems are using the same modulation scheme.  
Dial Backup Operation  
Modems do not establish a PSTN link when the Private line fails  
Check that the communicating modems are configured to support dial  
backup, as described in the AccessBuilder 7000 AT Command Reference.  
Check that one modem is configured to initiate the backup (i.e. is the  
master modem, and has the backup telephone number stored in its  
directory location 8) and the other modem is configured to be a slave  
(its directory location 8 is empty).  
Check that both modems are using the same modulation scheme over  
their PSTN line.  
 
     
MODEM SPECIFICATION AND  
INTERFACE PIN ASSIGNMENTS  
A
Transmitter / Receiver Specifications  
Modulation  
CCITT V.34 (33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800,  
14400, 12000, 9600, 7200, 4800, 2400 bps)  
Non-proprietary V.32terbo (19200, 16800, 14400, 12000, 9600, 7200,  
4800 bps)  
CCITT V.32bis (14400, 12000, 9600, 7200, 4800 bps)  
CCITT V.32 (9600, 4800 bps)  
CCITT V.22bis (2400 bps)  
CCITT V.22 (1200 bps)  
CCITT V.21 (300 bps)  
Bell 212A (1200 bps)  
Bell 103J (300 bps)  
Operation  
2-wire or 4-wire synchronous/asynchronous private line, or 2-wire  
PSTN operation.  
Output level  
Selectable 0 dBm to -15 dBm. 600 ohms impedance. (UK versions set to  
-9 dBm for PSTN operation or -13 dBm for private wire.)  
 
         
A-2  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
Data Input  
Serial binary. Complies with CCITT V.28. Accepts levels 3 volts to 25  
volts. (+)= space (-)= mark. Single wire ground return. 3000 to 7000  
ohms load.  
Data Output  
Serial binary. Complies with CCITT V.28 12 volts nominal. Output  
impedance 300 ohms.  
Synchronization  
RTS/CTS delay dependent on modulation format.  
Equalizer  
Automatic adaptive equalizer.  
Error correction  
V.42 LAPM and MNP4.  
Data compression  
V.42bis and MNP5.  
Autodial - Autoanswer  
Method  
Pulse dial. 10 pps rate. Make period 33 msec. Break period 67 msec (UK  
version). Interdigit period 800msec. Tone dial. On time 85 msec. ID time  
85 msec. Duty cycle 50%.  
Line Interface  
600 ohm impedance. Bell tinkle suppression provided. Old and new  
dial tone detection. Secondary dial tone detection for PABX use.  
Progress tones and answer tone detection.  
 
 
Physical Description  
A-3  
Protocols  
Extended AT command set. Non-volatile memory. 5 preset factory, 2  
user defined configurations and one power-up configuration. 20  
stored telephone numbers. AT or V.25bis asynchronous, bisynchronous  
and HDLC synchronous commands are entered via the DTE interface.  
ASCII or EBCDIC character set used in V.25bis command mode.  
Autoanswer  
CCITT V.25 compliant.  
Busy  
Busy out via AT command or DTR.  
Disconnect  
Call cleared selectable on loss of DTR; and/or no carrier for n seconds;  
and/or no data for n seconds; and/or a disconnect request is received  
from the remote modem in error correction.  
Test Functions  
Local analogue loop, local digital loop, or remote digital loop available  
using AT commands.  
Physical Description  
Power  
16V ac, 47 to 63 Hz, 1A max. Typical power consumption 11 Watts.  
Environment  
Temperature 0 to 40 degrees centigrade operating. -50 to 70 degrees  
centigrade storage.  
Relative humidity 5% to 95% non-condensing.  
Altitude to 3000 meters.  
 
 
A-4  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
Approvals Information  
This product complies with the electro-magnetic compatibility (EMC)  
requirements of EN 55022 Class A and EN 50082 (susceptibility).  
The product carries the CE certification mark to indicate conformance  
with the following EU directives:  
LVD (Low Voltage Directive (Safety) 73/23/EEC.  
EMC (Electro Magnetic Compatibility) Directive 89/336/EEC.  
TTE (Telecommunication Terminal Equipment) Directive 91/263/EEC.  
This product also meets the safety requirements of EN41003 and EN60950.  
See also the FCC and CSA statements at the back of this guide.  
General Approvals Requirements  
This section pertains to the approval of the modems, and to your country’s  
approvals board requirements and notices for use of these modems. Users  
of this module should pay particular attention to this information. This unit  
is approved for connection to the telecommunications systems specified  
in the instructions for use, subject to the conditions set out in them.  
Each modem is suitable for connection to the general switched telephone  
network (GSTN/PSTN) and extensions on compatible PABXs. It is also  
suitable for use on point-to-point private circuits, omnibus or multipoint  
circuits, using two or four wire termination (provided by Approved  
Telecommunication Operators), or to a relevant branch system.  
If any other apparatus, including cable or wiring, is to be connected  
between the apparatus and the point of connection to a 2-wire or  
4-wire speech band circuit, then all that other apparatus shall conform  
to the following:  
The overall transmission characteristics of all that other apparatus shall be  
such as to introduce no material effect upon the electrical conditions  
presented to one another by the apparatus and the digital circuit.  
 
   
Approvals Information  
A-5  
All the other apparatus shall comprise only:  
Apparatus approved (see note) for the purpose of connection  
between the apparatus and the digital circuit; and  
Cable or wiring complying with a code of practice for the  
installation of apparatus covered by this standard or such other  
requirements as may be applicable.  
Such apparatus may have been approved subject to limitations on its  
use.  
This modem is suitable for use on telephone lines provided with  
loop-disconnect or multi-frequency (MF) dialling facilities.  
This modem is suitable for household, office and similar indoor use, but is  
not suitable for use on an extension to a payphone, or a 1+1 carrier system.  
This unit may be used on circuits with CEPT L1 signalling at a nominal  
frequency of 2280 Hz. It does not require signalling or otherwise  
employ the frequency range 0 Hz to 200 Hz and there is no  
requirement for DC from the telephone line for correct operation.  
This unit causes a line voltage drop of 0.2 V at a line current of 40 mA  
Interference and Safety Requirements  
Radio frequency interference may be caused by incorrect operation or  
inadequate maintenance of this equipment. This unit is intended for  
use with screened digital cables.  
If any of your apparatus is not operating correctly, you should  
immediately remove it from the telephone line as this may harm the  
telephone network (GSTN).  
The approval of this unit for connection to GSTN or private speech  
band circuits is invalid if the apparatus is subject to modification in any  
material way not authorized or if it is used with or connected to  
internal software which has not been formally accepted.  
 
 
A-6  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
CAUTION: Danger of explosion if the battery is incorrectly replaced.  
Replace only with the same or equivalent type of battery as specified  
by the manufacturer. A used battery must be disposed of in accordance  
with the manufacturer’s instructions.  
PBX and PABX Application  
This unit has been approved for use of the following facilities.  
Loop-disconnect and multi-frequency signalling.  
Storage of telephone numbers for retrieval by a predetermined code.  
Detection of initial proceed indication.  
Detection of secondary proceed indication.  
Operation in the absence of proceed indication.  
Automatic dialling facilities.  
Tone detection, for example, ring tone, busy tone.  
Automatic answering of incoming calls.  
Automatic clearing from call originating end.  
Call progress monitor.  
Series connection (via optional cable).  
Modem.  
Any other usage will invalidate the approval of the apparatus if as a  
result it then ceases to conform to the standards against which  
approval was granted.  
This unit is only approved for compatible PBXs. The supplier of your  
unit should be consulted for an up-to-date list of PBXs with which this  
unit is compatible.  
There is no guarantee of correct working in all circumstances. Any  
difficulty should be referred to the supplier of the unit.  
This unit is suitable for connection to PBXs which return secondary  
proceed indication.  
 
 
Approvals Information  
A-7  
Ringer Equivalence  
REN is a guide to the maximum number of apparatus (for example,  
telephones) that can be simultaneously connected to one telephone  
line. The REN value of each apparatus is added together and must not  
exceed 4. Unless otherwise marked, a telephone can be assumed to  
have a REN of 1.0. Each modem on this unit has a ringer equivalence  
number (REN) of 4.0.  
 
 
A-8  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
DTE Port Pin Assignments  
Each modem is equipped with a single serial port marked DTE, which  
can be used to enter asynchronous AT or V.25bis commands, and pass  
asynchronous or synchronous user data. This is a female 26-pin V.24  
connector and can be used with X.21/V.11, v.24/V.28 or V.35/V.36  
signalling. The cable pin-outs for each type of cable are shown below.  
X.21/V.11  
The DTE port terminates with a 26-way miniature SCSI connector. The port  
can be configured to support V.11 signalling characteristics. The DTE port  
connecting cable is not supplied with the module. The following signalling  
characteristics should be observed when purchasing or fabricating a  
suitable cable.  
 
     
DTE Port Pin Assignments  
A-9  
V.24/V.28  
The DTE port terminates with a 26-way miniature SCSI connector.  
The port can be configured to support V.24 or V.28 signalling  
characteristics. The DTE port connecting cable is not supplied with the  
module. The following signalling characteristics should be observed  
when purchasing or fabricating a suitable cable.  
 
 
A-10  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
V.35/V.36  
The DTE port terminates with a 26-way miniature SCSI connector.  
The port can be configured to support V.36 signalling characteristics.  
The DTE port connecting cable is not supplied with the module. The  
following signalling characteristics should be observed when  
purchasing or fabricating a suitable cable.  
 
 
PSTN Port Cable Pin Assignments  
A-11  
PSTN Port Cable Pin Assignments  
Each modem on the communications card is equipped with a single  
PSTN line port, which is accessed via the appropriate DIAL LINE socket  
on the card’s interface module (refer to the rear panel diagram in  
Section 1.2 for an exact reference of which socket services which  
modem on the communications card). This is an RJ11 type socket, that  
would typically be connected to a PSTN telephone wall socket using a  
cable conforming to the wiring diagram shown below:  
 
 
A-12  
APPENDIX A: MODEM SPECIFICATION AND INTERFACE PIN ASSIGNMENTS  
Private Line Port Cable Pin Assignments  
Each modem on the communications card is equipped with a single  
Private line port supporting either a 2- or 4-wire connection, which is  
accessed via the appropriate PRIVATE LINE socket on the card’s interface  
module (refer to the rear panel diagram in Section 1.2 for an exact  
reference of which socket services which modem on the  
communications card). This is an RJ11 type socket, that would typically  
be connected to a 2- or 4-wire private line outlet using a cable  
conforming to the wiring diagram shown below:  
 
 
TECHNICAL SUPPORT  
B
3Com provides easy access to technical support information through  
the variety of services described in this appendix.  
On-line Technical Services  
3Com offers worldwide product support seven days a week, 24 hours a  
day, through the following on-line systems:  
3Com Bulletin Board Service (3ComBBS)  
World Wide Web site  
3Com Bulletin Board Service  
3ComBBS contains patches, software, and drivers for all 3Com products,  
as well as technical articles. This service is available via modem or ISDN  
seven days a week, 24 hours a day.  
Access by Modem  
To reach the service by modem, set your modem to 8 data bits, no  
parity, and 1 stop bit.  
 
               
B-2  
APPENDIX B: TECHNICAL SUPPORT  
Call the telephone number nearest you:  
Country  
Australia  
France  
Data Rate  
Telephone Number  
(61) (2) 9955 2073  
(33) (1) 69 86 69 54  
up to 14400 bps  
up to 14400 bps  
up to 9600 bps  
Germany  
(49) (89) 627 32 188 or (49) (89) 627 32  
189  
Hong Kong  
up to 14400 bps  
(852) 2537 5608  
(39) (2) 273 00680  
(81) (3) 3345 7266  
(65) 534 5693  
Italy (fee required) up to 14400 bps  
Japan  
Singapore  
Taiwan  
U.K.  
up to 14400 bps  
up to 14400 bps  
up to 14400 bps  
up to 28800 bps  
up to 28800 bps  
(886) (2) 377 5838  
(44) (1442) 278278  
(1) (408) 980 8204  
U.S.  
Access by ISDN  
ISDN users can dial-in to 3ComBBS using a digital modem for fast  
access up to 56 Kbps. To access 3ComBBS using ISDN, dial the  
following number:  
(1) (408) 654-2703  
World Wide Web Site  
Access the latest networking information on 3Com’s World Wide Web  
site by entering our URL into your Internet browser:  
This service features news and information about 3Com products,  
customer service and support, 3Com’s latest news releases, selected  
articles from 3TECH™ (3Com’s award-winning technical journal) and  
more.  
 
   
Support from Your Network Supplier  
B-3  
Support from Your Network Supplier  
If additional assistance is required, contact your network supplier.  
Many suppliers are authorized 3Com service partners who are qualified  
to provide a variety of services, including network planning, installation,  
hardware maintenance, application training, and support services.  
When you contact your network supplier for assistance, have the  
following information ready:  
Diagnostic error messages  
A list of system hardware and software, including revision levels  
Details about recent configuration changes, if applicable  
If you are unable to contact your network supplier, see the following  
section on how to contact 3Com.  
 
   
B-4  
APPENDIX B: TECHNICAL SUPPORT  
Support from 3Com  
If you are unable to receive support from your network supplier,  
technical support contracts are available from 3Com.  
In the U.S. and Canada, call (800) 876-3266 for customer service.  
If you are outside the U.S. and Canada, contact your local 3Com sales  
office to find your authorized service provider:  
Country  
Telephone Number  
Country  
Telephone Number  
Australia  
(Sydney)  
(61) (2) 959 3020  
Japan  
(81) (3) 33457251  
(Melbourne) (61) (3) 653 9515  
Mexico  
(525) 531 0591  
06 0227788  
Belgium*  
0800 71429  
Netherlands*  
Norway*  
Singapore  
South Africa  
Spain*  
Brazil  
(55) (11) 546 0869  
(905) 882 9964  
800 17309  
800 13376  
Canada  
(65) 538 9368  
(27) (11) 803 7404  
900 983125  
Denmark*  
Finland*  
France*  
0800 113153  
05 917959  
Sweden*  
Taiwan  
020 795482  
Germany*  
Hong Kong  
0130 821502  
(852) 868 9111  
(886) (2) 577 4352  
(971) (4) 349049  
United Arab  
Emirates  
Ireland*  
Italy*  
1 800 553117  
1678 79489  
U.K.*  
U.S.  
0800 966197  
(1) (408) 492 1790  
* These numbers are toll-free.  
 
     
Returning Products for Repair  
B-5  
Returning Products for Repair  
A product sent directly to 3Com for repair must first be assigned a  
Return Materials Authorization (RMA) number. A product sent to 3Com  
without an RMA number will be returned to the sender unopened, at  
the sender’s expense.  
To obtain an RMA number, call or fax:  
Country  
Telephone Number  
Fax Number  
U.S. and Canada  
Europe  
(800) 876 3266, option 2  
31 30 60 29900, option 5  
(408) 764 7120  
(44) (1442) 275822  
(1) (408) 764 7290  
Outside Europe, U.S., and Canada (1) (408) 492 1790  
11/29/95  
 
   
B-6  
APPENDIX B: TECHNICAL SUPPORT  
 
INDEX  
Numerics  
3Com Bulletin Board Service (3ComBBS) D-1  
3Com sales offices D-4  
installation 2-2  
front card 2-4  
prerequisites 1-7  
A
ALARM LED 2-7  
ALERT LED 2-7  
ANS LED 2-6  
B
bulletin board service D-1  
N
network supplier support D-3  
C
cable pin-outs A-8  
CH 1 LED 2-7  
O
CH 2 LED 2-7  
CH 3 LED 2-7  
on-line technical services D-1  
COMP LED 2-6  
CONN LED 2-6  
connecting cables 2-5  
CORR LED 2-6  
P
pack contents 1-6  
ports 2-5  
pre-installation requirements 1-7  
PSTN line ports 2-5  
push button 2-7  
PWR LED 2-7  
D
DTE ports 2-5  
F
R
features 1-2  
rear card installation 2-3  
REC LED 2-7  
front card installation 2-4  
returning products for repair D-5  
 
 
2
INDEX  
S
SEND LED 2-7  
T
technical information A-1  
technical support D-1  
TERM LED 2-6  
TEST LED 2-7  
Triple Modem  
features 1-2  
overview 1-1  
typical applications 1-5  
troubleshooting 3-1  
typical applications 1-5  
V
V.32terbo 1-3  
 
LIMITED WARRANTY  
HARDWARE: 3Com warrants its hardware products to be free from defects in workmanship and materials,  
under normal use and service, for the following lengths of time from the date of purchase from 3Com or its  
Authorized Reseller:  
Internetworking products  
One year  
Network adapters  
Lifetime  
Ethernet stackable hubs and unmanaged Ethernet fixed port repeaters  
Lifetime*  
(One year if not registered)  
*Power supply and fans in these stackable hubs and unmanaged repeaters One year  
Other hardware products  
Spare parts and spares kits  
One year  
90 days  
If a product does not operate as warranted above during the applicable warranty period, 3Com shall, at its  
option and expense, repair the defective product or part, deliver to Customer an equivalent product or part to  
replace the defective item, or refund to Customer the purchase price paid for the defective product. All  
products that are replaced will become the property of 3Com. Replacement products may be new or  
reconditioned. Any replaced or repaired product or part has a ninety (90) day warranty or the remainder of the  
initial warranty period, whichever is longer.  
3Com shall not be responsible for any software, firmware, information, or memory data of Customer contained  
in, stored on, or integrated with any products returned to 3Com for repair, whether under warranty or not.  
SOFTWARE: 3Com warrants that the software programs licensed from it will perform in substantial  
conformance to the program specifications therefor for a period of ninety (90) days from the date of purchase  
from 3Com or its Authorized Reseller. 3Com warrants the media containing software against failure during the  
warranty period. No updates are provided. 3Com's sole obligation with respect to this express warranty shall be  
(at 3Com's discretion) to refund the purchase price paid by Customer for any defective software products, or to  
replace any defective media with software which substantially conforms to 3Com's applicable published  
specifications. Customer assumes responsibility for the selection of the appropriate applications program and  
associated reference materials. 3Com makes no warranty or representation that its software products will work  
in combination with any hardware or applications software products provided by third parties, that the  
operation of the software products will be uninterrupted or error free, or that all defects in the software  
products will be corrected. For any third party products listed in the 3Com software product documentation or  
specifications as being compatible, 3Com will make reasonable efforts to provide compatibility, except where  
the non-compatibility is caused by a "bug" or defect in the third party's product.  
STANDARD WARRANTY SERVICE: Standard warranty service for hardware products may be obtained by  
delivering the defective product, accompanied by a copy of the dated proof of purchase, to 3Com's Corporate  
Service Center or to an Authorized 3Com Service Center during the applicable warranty period. Standard  
warranty service for software products may be obtained by telephoning 3Com's Corporate Service Center or an  
Authorized 3Com Service Center, within the warranty period. Products returned to 3Com's Corporate Service  
Center must be pre-authorized by 3Com with a Return Material Authorization (RMA) number marked on the  
outside of the package, and sent prepaid, insured, and packaged appropriately for safe shipment. The repaired  
or replaced item will be shipped to Customer, at 3Com's expense, not later than thirty (30) days after receipt of  
the defective product by 3Com.  
WARRANTIES EXCLUSIVE: IF A 3COM PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE, CUSTOMER'S  
SOLE REMEDY FOR BREACH OF THAT WARRANTY SHALL BE REPAIR, REPLACEMENT, OR REFUND OF THE  
PURCHASE PRICE PAID, AT 3COM'S OPTION. TO THE FULL EXTENT ALLOWED BY LAW, THE FOREGOING  
WARRANTIES AND REMEDIES ARE EXCLUSIVE AND ARE IN LIEU OF ALL OTHER WARRANTIES, TERMS, OR  
CONDITIONS, EXPRESS OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW, STATUTORY OR OTHERWISE,  
INCLUDING WARRANTIES, TERMS, OR CONDITIONS OF MERCHANTABILITY, FITNESS FOR A PARTICULAR  
PURPOSE, AND SATISFACTORY QUALITY. 3COM NEITHER ASSUMES NOR AUTHORIZES ANY OTHER PERSON TO  
ASSUME FOR IT ANY OTHER LIABILITY IN CONNECTION WITH THE SALE, INSTALLATION, MAINTENANCE OR USE  
OF ITS PRODUCTS.  
 
3COM SHALL NOT BE LIABLE UNDER THIS WARRANTY IF ITS TESTING AND EXAMINATION DISCLOSE THAT THE  
ALLEGED DEFECT IN THE PRODUCT DOES NOT EXIST OR WAS CAUSED BY CUSTOMER'S OR ANY THIRD  
PERSON'S MISUSE, NEGLECT, IMPROPER INSTALLATION OR TESTING, UNAUTHORIZED ATTEMPTS TO REPAIR OR  
MODIFY, OR ANY OTHER CAUSE BEYOND THE RANGE OF THE INTENDED USE, OR BY ACCIDENT, FIRE,  
LIGHTNING, OR OTHER HAZARD.  
LIMITATION OF LIABILITY. TO THE FULL EXTENT ALLOWED BY LAW 3COM ALSO EXCLUDES FOR ITSELF AND  
ITS SUPPLIERS ANY LIABILITY, WHETHER BASED IN CONTRACT OR TORT (INCLUDING NEGLIGENCE), FOR  
INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL, OR PUNITIVE DAMAGES OF ANY KIND, OR FOR LOSS OF  
REVENUE OR PROFITS, LOSS OF BUSINESS, LOSS OF INFORMATION OR DATA, OR OTHER FINANCIAL LOSS  
ARISING OUT OF OR IN CONNECTION WITH THE SALE, INSTALLATION, MAINTENANCE, USE, PERFORMANCE,  
FAILURE, OR INTERRUPTION OF ITS PRODUCTS, EVEN IF 3COM OR ITS AUTHORIZED RESELLER HAS BEEN  
ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, AND LIMITS ITS LIABILITY TO REPAIR, REPLACEMENT, OR  
REFUND OF THE PURCHASE PRICE PAID, AT 3COM'S OPTION. THIS DISCLAIMER OF LIABILITY FOR DAMAGES  
WILL NOT BE AFFECTED IF ANY REMEDY PROVIDED HEREIN SHALL FAIL OF ITS ESSENTIAL PURPOSE.  
Some countries, states, or provinces do not allow the exclusion or limitation of implied warranties or the  
limitation of incidental or consequential damages for certain products supplied to consumers, so the above  
limitations and exclusions may be limited in their application to you. This warranty gives you specific legal  
rights which may vary depending on local law.  
GOVERNING LAW: This Limited Warranty shall be governed by the laws of the state of California.  
3Com Corporation  
5400 Bayfront Plaza  
Santa Clara, CA 95052-8145  
(408) 764-5000  
3/18/96  
 
FCC CLASS A VERIFICATION STATEMENT  
This equipment has been tested with a class A computing device and has been found to comply with part 15  
of FCC Rules. Operation in a residential area may cause unacceptable interference to radio and TV receptions  
requiring the operator to take whatever steps are necessary to correct the interference.  
CSA Statement  
This digital apparatus does not exceed the Class A limits for radio noise emissions from digital apparatus as set  
out in the interference-causing equipment standard entitled “Digital Apparatus”, ICES-003 of the Department of  
Communications.  
Cet appareil numérique respecte les limites de bruits radioélectriques applicables aux appareils numériques de  
Classe A prescrites dans la norme sur le matériel brouilleur: “Appareils Numériques”, NMB-003 édictée par le  
ministre des Communications.  
European Statement  
This is a Class A product. In a domestic environment this product may cause radio interference, in which case  
the user may be required to take adequate measures.  
Information To The User  
If this equipment does cause interference to radio or television reception, which can be determined by turning  
the equipment off and on, the user is encouraged to try to correct the interference by one or more of the  
following measures:  
Reorient the receiving antenna.  
Relocate the equipment with respect to the receiver.  
Move the equipment away from the receiver.  
Plug the equipment into a different outlet so that equipment and receiver are on different branch circuits.  
If necessary, the user should consult the dealer or an experienced radio/television technician for additional  
suggestions. The user may find the following booklet prepared by the Federal Communications Commission  
helpful:  
How to Identify and Resolve Radio-TV Interference Problems  
This booklet is available from the U.S. Government Printing Office, Washington, DC 20402, Stock No.  
004-000-00345-4.  
In order to meet FCC emissions limits, this equipment must be used only with cables which comply with IEEE  
802.3.  
 
 
 

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