US Robotics Dual 56K Manuale utente

http://www.3com.com/

Dual 56K LAN Modem

User Guide

MODEL NO.

3C888

Part No. 1.018.1752

Published May 2000

http://www.3com.com/

3Com Corporation

5400 Bayfront Plaza

Santa Clara, California

95052-8145

3Com Corporation, 2000.

reproduced in any form or by any means or used to make any derivative work (such as translation,

transformation, or adaptation) without permission from 3Com Corporation.

3Com Corporation reserves the right to revise this documentation and to make changes in content from

time to time without obligation on the part of 3Com Corporation to provide notiﬁcation of such revision or

change.

3Com Corporation provides this documentation without warranty of any kind, either implied or expressed,

including, but not limited to, the implied warranties of merchantability and ﬁtness for a particular purpose.

3Com may make improvements or changes in the product(s) and/or the program(s) described in this

documentation at any time.

UNITED STATES GOVERNMENT LEGENDS:

If you are a United States government agency, then this documentation and the software described herein

are provided to you subject to the following restricted rights:

For units of the Department of Defense:

Restricted Rights Legend:

Use, duplication, or disclosure by the Government is subject to restrictions as set

forth in subparagraph (c) (1) (ii) for Restricted Rights in Technical Data and Computer Software Clause at 48

C.F.R. 52.227-7013. 3Com Corporation, 5400 Bayfront Plaza, Santa Clara, California 95052-8145.

For civilian agencies:

Restricted Rights Legend:

Use, reproduction, or disclosure is subject to restrictions set forth in subparagraph

(a) through (d) of the Commercial Computer Software - Restricted Rights Clause at 48 C.F.R. 52.227-19 and

the limitations set forth in 3Com Corporation’s standard commercial agreement for the software.

Unpublished rights reserved under the copyright laws of the United States.

Unless otherwise indicated, 3Com registered trademarks are registered in the United States and may or may

not be registered in other countries.

3Com, OfﬁceConnect, and U.S. Robotics are registered trademarks of 3Com Corporation. 3ComFacts is a

service mark of 3Com.

Acrobat and Adobe are registered trademarks of Adobe Systems, Incorporated. America Online is a

registered trademark of America Online, Inc. Macintosh is a registered trademark of Apple Computer.

Compuserve is a registered trademark of Compuserve Interactive Services, Inc. LZS is a registered trademarks

of hi/fn, Inc. Pentium is a registered trademark of Intel Corporation. IBM is a trademark of International

Business Machines Corporation. Windows and Windows NT are registered trademarks of Microsoft

Corporation. Netscape Navigator is a registered trademark of Netscape Communications. IPX is a registered

trademark of Novell, Inc. UL is a trademark of Underwriters Laboratory, Inc.

Other brand and product names may be registered trademarks or trademarks of their respective holders.

Guide written by Eric Heller.

I

MPORTANT

S

AFETY

I

NFORMATION

Important Safety

Information

WARNING:

Warnings contain directions that you must follow for your personal safety. Follow all

instructions carefully.

Please read the following information carefully and thoroughly before installing the unit:

■

Take exceptional care during the installation and removal of the unit.

■

Locate the unit close to the mains socket outlet, and ensure that the mains socket is accessible.

■

Use the power adapter supplied with the unit to ensure compliance with national and

international safety standards. If there is no power adapter supplied, the mains cordset used must

be compliant with the local and national regulations of the target country and must not violate

the safety approval of the product (refer to the Approvals section at the back of this manual).

■

Disconnect the power adapter before moving the unit. Power can only be disconnected from the

unit by removing the power adapter from the unit or from the socket outlet.

■

Only connect apparatus complying with the relevant interface requirements to the ports on this

unit. The safety status of the ports on this equipment are as follows.

■

Ports identiﬁed by the labels LAN and Phone = SELV.

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).

■

There are no user-replaceable fuses or user-serviceable parts inside the unit. If there is a physical

problem with the unit that cannot be solved with problem solving actions in this guide, contact

the 3Com reseller from whom the equipment was purchased.

■

If the units are stackable, only stack similar units.

WARNING: Twisted Pair RJ45 data ports.

These are shielded RJ45 data sockets. They cannot be

used as telephone sockets. Only connect RJ45 data connectors to these ports.

Wichtige

Sicherheits-Informatio

nen

WARNUNG:

Warnungen enthalten Anweisungen, die Sie zu Ihrer persönlichen Sicherheit befolgen

müssen. Bitte halten Sie sich daran.

Bitte lesen Sie die folgenden Informationen aufmerksam, ehe Sie die Einheit installieren:

■

Lassen Sie bei Installation und Abbau besondere Vorsicht walten.

■

Stellen Sie die Einheit in der Nähe einer Stromquelle auf und achten Sie darauf, daß diese

zugänglich ist.

■

Verwenden Sie immer den mitgelieferten Netzadapter, damit die Einhaltung nationaler und

internationaler Sicherheitsnormen gewährleistet ist. Wurde kein Adapter mitgeliefert, muß das

verwendete Netzkabel den lokalen und nationalen Bestimmungen des Landes entsprechen und

darf die Sicherheitsbestimmungen des Produkts (siehe den entsprechenden Abschnitt am Ende

dieses Handbuchs) nicht verletzen.

■

Trennen Sie den Netzadapter von der Stromversorgung, bevor Sie die Einheit bewegen. Die

Einheit kann nur von der Stromversorgung getrennt werden, indem Sie die Verbindung des

Netzadapters entweder von Einheit oder der Stromquelle trennen.

■

Schließen Sie nur Geräte an den Schnittstellen dieser Einheit an, die den

Interface-Voraussetzungen entsprechen. Die Sicherheitsmerkmale der Schnittstellen dieses Geräts

sind:

■

Schnittstellen mit der Bezeichnung LAN und Phone = SELV. SELV (Safety Extra Low Voltage) ist

ein sekundärer Schaltkreis, der unter normalen und Single-Fault-Bedingungen so eingerichtet

ist, daß die Spannung zwischen zwei zugänglichen Bauteilen einen Sicherheitswert nicht

übersteigt (42,2 V Spitzenspannung bzw. 60 V Gleichspannung).

■

Die Einheit enthält keine Sicherungen oder sonstige Bauteile, die vom Benutzer ausgewechselt

oder gewartet werden können. Sollte ein physikalischer Fehler auftreten, der mit den in diesem

Handbuch beschriebenen Maßnahmen nicht zu beheben ist, setzen Sie sich mit dem

3Com-Vertreter in Verbindung, bei dem Sie das Gerät erworben haben.

■

Bei stapelfähiger Konstruktion nur gleichartige Einheiten verwenden.

WARNUNG: Twisted Pair RJ45-Datenschnittstellen.

Dies sind abgeschirmte RJ45-Schnittstellen,

die nicht für Telefonsignale verwendet werden können. Schließen Sie an diesen Schnittstellen nur

RJ45-Datenstecker an.

Important Notice de

Securite

AVERTISSEMENT:

les avertissements présentent des instructions que vous devez suivre très

attentivement pour votre sécurité personnelle.

Veuillez lire les informations suivantes attentivement avant l'installation de l'appareil.

■

Soyez très prudents pendant toute la durée de l'installation et du déplacement de l'appareil.

■

Placez l'appareil près d'une prise murale qui doit rester accessible à tout instant.

■

Utilisez l'adaptateur électrique fourni avec l'appareil pour garantir la conformité totale aux

normes de sécurité nationales et internationales. Si aucun adaptateur n'est fourni, le câble

électrique utilisé doit être conforme aux normes locales et nationales du pays et ne doit en aucun

cas contrevenir aux normes de sécurité d'utilisation de l'appareil (veuillez consulter la section

Approvals (Agréments) au dos du présent manuel).

■

Déconnectez l'adaptateur électrique avant de déplacer l'appareil. L'alimentation ne peut être

déconnectée de l'appareil qu'en retirant l'adaptateur de l'appareil ou de la prise de courant.

■

Ne connectez l'appareil qu'en conformité avec les exigences techniques des ports de connexion

de l'appareil. Les normes de sécurité de chaque port sont les suivantes :

■

Les ports identiﬁés par les étiquettes LAN et Phone = SELV.

Les circuits SELV (Safety Extra Low Voltage, très basse tension de sécurité) sont des circuits

secondaires qui sont conçus et protégés pour qu'en conditions normales et à défaillance

unique, la tension n'excède jamais la valeur de sécurité de 42,2 V en crête, ou 60 V DC.

■

L'appareil ne contient aucun fusible remplaçable par l'utilisateur ni aucune pièce dont la

maintenance peut être effectuée par l'utilisateur. Si un problème physique survient dans

l'appareil, qui ne peut être résolu au moyen des techniques de dépannage du présent manuel,

contactez le revendeur 3Com qui vous a fourni l'appareil.

■

Si vous disposez de plusieurs appareils empilables sur racks, n'empilez que les appareils similaires.

AVERTISSEMENT:

ports de données RJ45 à paires torsadées.

Il s'agit de prises de données RJ45

blindées. Elles ne peuvent être utilisées comme prises de téléphone. Elles ne doivent recevoir que les

connecteurs de données RJ45.

Medidas de Seguridad

Importantes

ADVERTENCIA:

las advertencias contienen instrucciones que es preciso seguir al pie de la letra para

evitar daños personales.

Antes de instalar la unidad, lea atentamente la siguiente información.

■

Tome todas las precauciones necesarias a la hora de instalar o desinstalar la unidad.

■

Coloque la unidad cerca de una toma de corriente de fácil acceso.

■

Utilice el adaptador de corriente suministrado con la unidad, de este modo se asegura el pleno

cumplimiento de las normas de seguridad nacionales e internacionales. En caso de no recibir un

adaptador con la unidad, deberá utilizar un cable que responda a los requisitos estipulados por la

normativa local o nacional pertinente y que no contravenga la garantía de seguridad del producto

(consulte la sección relativa a este punto al final de esta guía).

■

Desenchufe el adaptador antes de mover la unidad. La única forma de interrumpir el paso de

corriente consiste en desenchufar el adaptador de la unidad o de la toma de corriente.

■

No deben conectarse a los puertos de la unidad aparatos que no cumplan los requisitos de la

interfaz en uso. Los puertos de la unidad son de los siguientes tipos:

■

Puertos con etiqueta LAN o Phone= SELV.

SELV (Safety Extra Low Voltage) es un circuito secundario diseñado para que el voltaje entre

dos puntos accesibles no exceda límites seguros (42,2 V punta ó 60 V CC) en circunstancias

normales o de fallo simple.

■

La unidad no contiene fusibles ni otros componentes que el usuario pueda cambiar o reparar. De

producirse problemas cuya resolución no se explique en esta guía, póngase en contacto con el

proveedor de 3Com.

■

Si las unidades que posee son apilables, acople las que sean similares entre sí.

ADVERTENCIA: puertos de datos de par trenzado RJ45.

Son enchufes blindados RJ45 a los que

sólo deben acoplarse conectores de datos RJ45. No pueden utilizarse como enchufes telefónicos.

Informazioni

Importanti per la

Sicurezza

AVVERTENZA:

il testo delle avvertenze riporta importanti istruzioni alle quali occorre attenersi per

motivi di sicurezza. Seguire attentamente tutte le istruzioni.

Prima di installare l'unità, leggere attentamente le informazioni riportate di seguito.

■

Procedere con estrema cautela durante l'installazione e la rimozione dell'unità.

■

Collocare l'unità vicino a una presa di corrente e verificare che la presa sia accessibile.

■

Per garantire la conformità alle norme di sicurezza nazionali e internazionali, usare l'adattatore di

corrente fornito con l'unità. Se l'adattatore non è compreso, il cavo alimentatore deve essere

conforme alle norme locali e nazionali del paese di destinazione nonché all'omologazione di

sicurezza del prodotto (per ulteriori informazioni consultare la sezione relativa alle omologazioni

riportata alla ﬁne del manuale).

■

Scollegare l'adattatore prima di spostare l'unità. Per scollegare l'unità occorre rimuovere

l'adattatore dall'unità stessa o dalla presa di corrente.

■

Collegare alle porte dell'unità solamente apparecchi conformi ai requisiti della relativa interfaccia.

Le speciﬁche riguardanti la sicurezza delle porte sono le seguenti:

■

Porte contrassegnate dalle targhette LAN e Phone = SELV. SELV (Safety Extra Low Voltage) è

un circuito secondario ideato e protetto in modo tale che, in condizioni normali e in caso di

un unico guasto, la tensione tra due parti accessibili qualsiasi non superi il valore di sicurezza

(42,2 V picco o 60 V CC).

■

All'interno dell'unità non vi sono fusibili sostituibili dall'utente o parti la cui manutenzione può

essere effettuata dall'utente. Se si verifica un problema che non si è in grado di risolvere

seguendo le istruzioni per la risoluzione dei problemi riportate nel presente manuale, contattare il

rivenditore 3Com presso il quale si è acquistata l'unità.

■

Se le unità sono impilabili, impilare solamente unità simili.

AVVERTENZA: porte dati RJ45 per doppino intrecciato.

Si tratta di prese dati RJ45 schermate e

non possono essere utilizzate come prese telefoniche. Collegare solamente connettori dati RJ45 a

queste porte.

Additional Safety

Information

■

Only connect apparatus complying with the relevant interface requirements to the ports on

this unit.

■

Disconnect the power adapter before moving the unit.

■

Retain this user’s guide for later use and pass it on in the event of change of ownership of

the unit.

■

Protect the unit from sudden, transient increases and decreases in electrical power by ﬁtting

an in-line surge suppressor or uninterruptible power supply. 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 case or cover is not correctly ﬁtted or if it is damaged.

■

If the unit begins to make an odd noise, smell or smoke.

■

If the unit shows signs of a distinct change in performance.

■

Never install telephone wires during a lightning 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 use a telephone, which is connected to the unit, to report a gas leak in the vicinity of

the leak.

■

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.

■

Only equipment approved for use by your telecom company can be connected to the

telephone port.

■

Avoid using a telephone, which is connected to the unit (other than a cordless type), during

an electrical storm.

■

Equipment connected to the telephone port must be located in the same building as the

unit.

■

Be sure nothing rests on the units 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. Allow 25mm (1inch) around the unit to

provide adequate air circulation.

■

Install the unit in a clean area that is free from dust or extreme temperatures.

■

Allow a clearance gap of at least a 150 mm (6 inches) from the rear panel of the unit, to

allow for cable access.

■

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.

T

ABLE

OF

C

ONTENTS

I

MPORTANT

S

AFETY

I

NFORMATION

3

Wichtige Sicherheits-Informationen 3

Important Notice de Securite 4

Medidas de Seguridad Importantes 4

Informazioni Importanti per la Sicurezza 5

Additional Safety Information 5

A

BOUT

T

HIS

G

UIDE

Introduction 11

How to Use This Guide 11

Conventions 12

Year 2000 Compliance 12

I

NTRODUCTION

Introduction 13

Applications 14

Hardware Description 16

Features 18

D

UAL

56K LAN M

ODEM

F

UNCTIONALITY

D

ESCRIPTION

LAN Side Connectivity: Installing an Ethernet Hub 21

Wan Side: The Two 56K Modems 22

Using the Modem Channels 22

Dial-in Functionality 25

Understanding Multilink PPP and Other Line Usage Options 27

The Virtual FAX Modem (Windows 95, 98, NT, and 2000) 28

Support for Virtual Private Networks (VPNs) 29

B

EFORE

Y

OU

B

EGIN

Package Contents 31

Before You Begin 31

Why Check TCP/IP and IP Address Settings? 32

Checking TCP/IP and IP Address Settings 32

Adding TCP/IP to Your Protocols List 34

Setting Up Your Computer If You Have a Static IP Address 39

INSTALLING THE DUAL 56K LAN MODEM

Before You Start the Installation 43

CONFIGURING THE DUAL 56K LAN MODEM FOR INTERNET ACCESS

Typical Conﬁguration 47

Changing the LAN Modem IP Address for Static IP Users 52

The LAN Modem Main Conﬁguration Page 53

Connecting an External Hub to the Dual 56K LAN Modem 56

CONFIGURING THE DUAL 56K LAN MODEM FOR PRIVATE NETWORK

A

CCESS

Before You Start the Conﬁguration 59

Conﬁguration Steps 60

Changing the LAN Modem IP Address for Static IP Users 67

The LAN Modem Main Conﬁguration Page 68

The LAN Modem Support Web Site 70

ADVANCED CONFIGURATION

Advanced Conﬁguration 71

Conﬁguring Additional Service Providers 71

Editing Service Provider Proﬁles 76

Associating Service Providers with Workstations on the LAN 76

Using a Connection Script 77

Conﬁguring LAN Parameters 81

Conﬁguring V.90 Modem Control Parameters 83

Changing Data Call Parameters 85

Specifying a WINS Server Address 87

Conﬁguring the Local DNS Table 88

Reserving DHCP Addresses 89

Changing Your Password 89

Locking and Unlocking the Conﬁguration 90

Using Selective Password Protection 91

Conﬁguring the LAN Modem from a Remote Location 91

Checking for Dual 56K LAN Modem upgrades 94

CONFIGURING THE DUAL 56K LAN MODEM FOR DIAL-IN SUPPORT

Understanding Dial-in Basics 95

Understanding the Three Dial-in Proﬁle Types 96

Part I. Conﬁguring the Server-side Dual 56K LAN Modem for Dial-in Support 99

Part II. Conﬁguring a Client Device for Dial-out Access 109

Conﬁguring Dial-in User Parameters 114

Placing a Call from a Client-side LAN Modem 118

PLACING, RECEIVING AND DISCONNECTING CALLS

Using the LAN Modem Desktop Manager (Windows only) 119

Placing Calls 119

Receiving Calls 121

Disconnecting Calls 122

TROUBLESHOOTING AND MAINTENANCE

Checking the Basics 125

Monitoring LEDs 125

Evaluating Symptoms and Solutions 126

Finding More Information 131

Contacting Technical Support 131

Downloading Firmware to Your Dual 56K LAN Modem 131

Resetting the Dual 56K LAN Modem 131

Reviewing Statistics 132

Synchronizing the LAN Modem Clock 134

NETWORKING PRIMER

What is a network? 137

INSTALLING AND USING THE VIRTUAL FAX MODEM

Installing the Virtual FAX Modem 147

CREATING A VIRTUAL PRIVATE NETWORK (VPN) TUNNEL

Creating a Virtual Private Network (VPN) Tunnel 151

FACTORY DEFAULTS

Dual 56K LAN Modem Factory Defaults 153

SPECIFICATIONS

Speciﬁcations 155

Year 2000 Compliance 155

GLOSSARY

3COM CORPORATION LIMITED LIFETIME WARRANTY

REGULATORY AND APROVAL INFORMATION

ABOUT THIS GUIDE

About This Guide provides an overview of this User Guide, describes guide

conventions, and shows you where to look for speciﬁc information.

Introduction This guide tells you how to install and conﬁgure the Dual 56K LAN Modem and

provides descriptions of key applications and networking concepts.

Audience Description This guide is intended for end users with no presumed level of expertise.

How to Use

This Guide

Table 1 shows you where to ﬁnd speciﬁc information in this guide.

Table 1 Speciﬁc Information

If you are looking for... Turn to...

An overview of the Dual 56K LAN Modem Chapter 1

A description of the Dual 56K LAN Modem hardware components Chapter 1

An explanation of the Dual 56K LAN Modem’s key functionality Chapter 2

Instructions on checking TCP/IP and IP address settings Chapter 3

Instructions on installing the Dual 56K LAN Modem Chapter 4

Instructions on configuring the Dual 56K LAN Modem for Internet access Chapter 5

Instructions on configuring the Dual 56K LAN Modem for private network access Chapter 6

Instructions on advanced configuration of the Dual 56K LAN Modem Chapter 7

Instructions on configuring the Dual 56K LAN Modem for dial-in support Chapter 8

Information on placing and disconnecting calls and using the Desktop Manager Chapter 9

Information on troubleshooting and maintenance Chapter 10

Background information on networking Appendix A

Information on installing and using the Virtual FAX Modem application Appendix B

Information on creating a virtual private network (VPN) tunnel Appendix C

Dual 56K LAN Modem factory default settings Appendix D

Technical specifications for the Dual 56K LAN Modem Appendix E

Glossary definitions for terms used in this guide Glossary

12 ABOUT THIS GUIDE

Conventions Table 2 and Table 3 list conventions that are used throughout this guide.

Year 2000 Compliance The OfﬁceConnect LAN Modem is Year 2000 compliant. Speciﬁcally, its system

clock is capable of accepting and storing dates including and beyond the year

2000. For information on Year 2000 compliance and 3Com products, visit the

3Com Year 2000 web page:

http://www.3com.com/products/yr2000.html.

Table 2 Notice Icons

Icon Notice Type Alerts you to...

Information note Important features or instructions

Caution Risk of personal safety, system damage, or loss of data

Warning Risk of severe personal injury

Table 3 Text Conventions

Convention Description

Commands The word “command” means you must enter the command exactly as

shown in text and press the Return or Enter key. Example:

To remove the IP address, enter the following command:

SETDefault!0 -IP NETaddr = 0.0.0.0

NOTE: This guide always gives the full form of a command in

uppercase and lowercase letters. However, you can abbreviate

commands by entering only the uppercase letters and the appropriate

value. Commands are not case-sensitive.

The words “enter”

and “type”

When you see the word “enter” in this guide, you must type

something and then press the Return or Enter key. Do not press the

Return or Enter key when an instruction simply says “type.”

[Key] names Key names appear in text in one of two ways:

■ Referred to by their labels, such as “the Return key” or “the Escape

key”

■ Written with brackets, such as [Return] or [Esc].

If you must press two or more keys simultaneously, the key names are

linked with a plus sign (+). Example:

Press [Ctrl]+[Alt]+[Del].

Menu commands

and buttons

Menu commands or button names appear in italics. Example:

From the Help menu, select Contents.

Words in italicized

type

Italics emphasize a point or denote new terms at the place where they

are defined in the text.

Words in bold-face

type

Bold text denotes key features.

1

INTRODUCTION

This chapter provides an overview of the OfﬁceConnect

®

Dual 56K LAN Modem,

referred to throughout this document as the Dual 56K LAN Modem, or simply as

the LAN Modem.

Introduction The Dual 56K LAN Modem is an easy-to-install, Local Area Network (LAN) to Wide

Area Network (WAN), analog IP router. The LAN Modem provides four 10BASE-T

Ethernet ports for LAN-side connections and two internal, V.90 ITU 56K-standard

modems for WAN-side connections, plus two additional analog ports for standard

analog equipment such as a phone and/or fax machine.

To conﬁgure the Dual 56K LAN Modem, you use a standard web browser on a

computer attached to the LAN Modem to access the LAN Modem’s web-based

conﬁguration screens. Afterwards, you can attach up to three additional

computers directly to the LAN Modem, or a combination of external hubs and

computers, to create WAN access for up to 25 users.

Dial-in and Dial-out

Access

The Dual 56K LAN Modem supports both dial-in and dial-out remote access. This

means that you can use the LAN Modem on either end of a LAN-to-WAN

connection: to call out from your local LAN to an already existing network (such as

the Internet or a private, corporate network), or to receive calls into your LAN from

up to ten previously-deﬁned remote sites. For calls to a private network via the

Internet, where security is a consideration, the LAN Modem also supports

pass-though VPN (Virtual Private Network) tunneling.

Dual 56K Analog

Modems

The V.90 56K ITU standard used on each of the Dual 56K’s internal modems

provides download speeds of up to 56K

1

for each analog line. The two modems

can be accessed independently on a ﬁrst-come, ﬁrst-served basis by any

combination of users dialing out from the LAN and users dialing in to the LAN for

separate, 56K connections. Or, the LAN Modem can be conﬁgured to provide one

high-speed connection at a time.

The Dual 56K LAN Modem is software upgradeable, allowing for easy upgrades to

new features and enhancements as they become available. Visit the LAN Modem

Web site for the latest ﬁrmware releases:

http://www.3com.com/support/docs/lanmodem.

1.Capable of receiving downloads at up to 56 Kbps and sending at up to 31.2 Kbps. Due to FCC regu-

lations, receiving speeds are limited to 53 Kbps. Actual speeds may vary. Requires compatible analog

phone line and server equipment. The Dual 56K LAN Modem complies with the V.90 ITU standard and

is backwards-compatible with all US Robotics 56K standards. Standard ofﬁcially determined in February,

1998; ratiﬁed in September, 1998.

14 CHAPTER 1: INTRODUCTION

Applications The primary applications for the Dual 56K LAN Modem are:

■ Local networking with shared, dial-out access to the Internet

■ Local networking with shared, dial-out access to a private network, such as a

remote corporate ofﬁce LAN (this can include indirect Internet access through

the private network’s Internet connection)

■ Local networking with shared, simultaneous dial-out access to the Internet and

a private network

■ Combined dial-in and dial-out access for several possible networking scenarios

(refer to Chapter 8 for speciﬁc dial-in applications).

The following diagrams illustrate the primary Dual 56K LAN Modem applications:

Local Networking with

Shared Internet Access

Users can share access to the Internet while they continue to network locally, as

shown in Figure 1.

Figure 1 Local Networking with Shared Internet Access

Local Networking with

Shared Private Network

Access

Users can share access to a remote private network, such as a corporate ofﬁce

LAN, while they continue to network locally. This can include indirect access to the

Internet through the private network’s Internet connection, as shown in Figure 2.

Figure 2 Local Networking with Remote Private Network Access

OfficeConnect

Dual 56K LAN Modem

Public telephone

network

Two analog POTs lines

Internet

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e

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t

P

o

w

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r

M

e

s

a

g

e

R

D

A

C

D

S

D

O

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R

D

A

C

D

S

D

O

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OfficeConnect Dual 56k LAN Modem

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Internet

Applications 15

Local Networking with

Shared Access to the

Internet and a Private

Network

Users can share simultaneous access to both the Internet and a remote private

network while they continue to network locally, as shown in Figure 3.

Figure 3 Local Networking with Shared Access to the Internet and a Remote Private

Network

Combined Dial-in and

Dial-out Access

Users can share access to the Internet or a remote private network and continue to

network locally, while a user dials in for access to a server or servers on the LAN, as

shown in Figure 4. (Other dial-in scenarios are possible. Refer to Chapter 8 for

speciﬁc applications.)

Figure 4 Local Networking and Dial-out Access with Dial-in Support

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LAN StatusMODEM 2MODEM 1

16 CHAPTER 1: INTRODUCTION

Hardware Description The following is an overview of the Dual 56K LAN Modem hardware, including the

function of the front panel LEDs and back panel connectors.

Front Panel LED

Description

The front panel contains the LEDs illustrated in Figure 5.

Figure 5 Dual 56K LAN Modem Front Panel

The functions of the front panel LEDs are described in Table 4. These front panel

LEDs indicate proper operation and display analog modem and Ethernet port

activity status.

Table 4 Front Panel LED Indicator Deﬁnitions

LED Color Description

Alert Amber Operational Status. Lit during power-on self-diagnostic test

or after pressing the reset button.

Off indicates that the unit has passed the diagnostic test and

is working properly.

Flashes if one or more of the diagnostics have failed or after

the unit is placed in firmware download mode and is awaiting

firmware upgrade.

Power Green Power Indicator. Remains lit as long as power is supplied to

the unit.

Message Not implemented.

AA (MODEM 1 or 2) Green Auto Answer. Shows the answer status for Modem 1 or 2,

as follows:

■ Flashes during an incoming call.

■ Remains lit for the duration of the call.

■ Off when the LAN Modem originates a call.

CD (MODEM 1 or 2) Green Carrier Detect. Remains lit for the indicated modem if the

Dual 56K LAN Modem receives a valid data signal (carrier)

from a remote modem (such as an ISP), indicating that data

transmission is possible.

RD (MODEM 1 or 2) Green Received Data. Flashes when the indicated modem receives

data from a remote site.

SD (MODEM 1 or 2) Green Send Data. Flashes when the indicated modem sends data to

a remote site.

OH (MODEM 1 or 2) Green Off Hook. Remains lit when the indicated modem has gone

off hook.

TX Green Ethernet Transmit Status. Flashes green when data is being

transmitted to the Ethernet LAN from the Dual 56K LAN

Modem.

Off indicates that no data is being transmitted to the Ethernet

LAN from the Dual 56K LAN Modem.

Alert

Pow

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RD

AA

CD

SD

OH

RD

AA

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LAN StatusMODEM 2MODEM 1

Hardware Description 17

Back Panel Connector

Description

The back panel contains the connectors illustrated in Figure 6.

Figure 6 Dual 56K LAN Modem Back Panel

From left to right, the back panel consists of the following:

■ Power: Connect the power module cable to this port.

■ RESET: Press this button to re-initialize or factory re-set the unit (refer to

Chapter 10 for instructions).

■ LAN 1, 2, 3, and 4: Connect up to four computers (or a combination of

computers and an external hub), to these four 10BASE-T Ethernet ports.

■ LINE 1: Connect one of the provided RJ-11 analog cables from the wall outlet

to this port.

■ PHONE 1: Connect an external analog device, such as a telephone or fax

machine, to this port.

■ LINE 2: Connect the second RJ-11 analog cable from the wall outlet to this

port.

■ PHONE 2: Connect an additional external analog device, such as a telephone

or fax machine, to this port.

COLL Amber Ethernet Collision Status. Flashes amber when some

collisions are taking place on the Ethernet LAN.

Off indicates that no collisions are taking place on the

Ethernet LAN.

Ports 1-4 Green Ethernet LAN Port Status. On indicates that the unit

detects the Ethernet link integrity signal from an attached

computer and operation is normal.

Flashes when the LAN Modem receives data on the

associated port.

Off indicates that the unit does not detect the Ethernet link

integrity signal. The Ethernet cable may not be properly

connected or the cable may be the wrong polarity.

Table 4 Front Panel LED Indicator Deﬁnitions (continued)

LED Color Description

10-30V DC

2A MAX

RESET

1

3

2

4

LAN

LINE 1 PHONE 1 LINE 2 PHONE 2

18 CHAPTER 1: INTRODUCTION

Features Ease of Installation and Use

■ Web-based, point-and-click user interface for easy conﬁguration

■ Automatic Internet conﬁguration veriﬁcation via your Internet Service Provider

(ISP)

■ Web-based, context-sensitive online help

■ Dial-in Wizard for easy conﬁguration of dial-in setup

■ LAN Modem Desktop Manager tool for easy management and stats

monitoring (Windows 95

®

, 98

®

, NT

®

and 2000

®

)

■ EZ- LAN Wizard, which optimizes workstation settings for use with the Dual

56K LAN Modem (Windows 95, 98, NT and 2000)

High Performance

■ Two internal 56K modems, capable of downloading at speeds of up to 112

Kbps

1

(without compression)

■ V.42/MNP 2-4 error control and V.42 bis/MNP 5 data compression

■ Hi/fn™ LZS

®

compression, which conforms to the following IETF RFCs: The PPP

Compression Control Protocol (RFC 1962) and PPP Stacker LZS Compression

Protocol (RFC 1974)

Connectivity

■ Two 56K integrated analog modems

■ Built-in four-port 10BASE-T, 10 Mbps Ethernet hub. Up to 25 users can be

supported by adding an external Ethernet hub

■ Two pass-through, analog voice ports for connecting up to two external analog

devices

■ Virtual Private Network (VPN) pass-through capability using client software

Virtual FAX Modem

■ Allows Windows users on the LAN to access one or both modems as if directly

connected through an RS-232 serial (COM) port.

■ Creates support for applications requiring a dedicated modem, such as Class

2.0 fax applications, and online services.

Routing

■ IP Routing

■ Dynamic or static IP addresses supplied by your service provider (WAN side)

■ Dynamic Host Conﬁguration Protocol (DHCP) server functionality on the LAN,

which automatically assigns an IP address to a newly-attached PC on the IP

network

■ Domain Name Service (DNS) server functionality for the LAN, which translates

the common, alphanumeric name of a device (for example,

“www.3com.com”) to its numeric IP address

1.Current FCC rules limit download speeds to 53Kbps per modem.

Features 19

■ Network Address Translation (NAT) between LAN and WAN, which allows

multiple users on the LAN to share a single remote connection and user

account.

■ Intelligent NAT, an enhancement to NAT which enables UDP applications to

work with the Dual 56K LAN Modem.

■ Multiplexing trafﬁc from several computers to remote destinations

Bandwidth Management

■ Automatic call initiation (also known as dial-on-demand routing)

■ Automatic disconnection of idle calls after a speciﬁed length of time

■ Multilink PPP, which combines two PPP calls on two analog lines into a single,

high-speed network connection.

■ Bandwidth on Demand using Bandwidth Allocation Control Protocol

(BACP)/Bandwidth Allocation Protocol (BAP), based on a speciﬁed threshold.

■ Dynamic Bandwidth Allocation (DBA), which allows you to place a voice or

data call while a Multilink PPP call is active.

■ Manual call connection and disconnection

Remote Management

■ Remote management via Web browser-based interface

■ Remote ﬁrmware upgrades

Protocols

■ IETF PPP (RFC 1661, 1662, 1663)

■ IETF Multilink PPP (RFC 1990)

■ IETF Password Authentication Protocol (PAP) and Challenge Handshake

Authentication Protocol (CHAP) security (RFC 1994)

■ MS-CHAP support (as deﬁned in Network Working Group Information Memo:

Microsoft PPP CHAP Extensions. S. Cob, Rev. 1.3 March 1997 including only

the functionality that keeps with IETF 1994).

■ IP address negotiation using IPCP (RFC 1332)

■ Network Address Translation (NAT) between LAN and WAN (RFC 1631)

■ Point-to-Point Tunneling Protocol (PPTP—PPTP draft-ietf-pppext-pptp-02.txt).

■ Microsoft Callback Control Protocol (CBCP)

■ BACP/BAP (RFC 2125)

■ LCP Extension Protocol (for Callback functionality) (RFC 1570)

■ Telnet Com Port Control Option (RFC 2217)

Error Control and Data Compression

■ ITU-T V.42

■ ITU-T V.42bis

■ MNP 2-5

20 CHAPTER 1: INTRODUCTION

Modulation Schemes

■ V.90 (backwards-compatible with all US Robotics 56K Standards)

■ ITU-T V.34+

■ ITU-T V.34

■ ITU-T V.32bis

■ ITU-T V.32

■ ITU-T V.22bis

■ ITU-T V.22

■ ITU-T V.23

■ Bell 212A

■ ITU-T V.21

■ Bell 103

Security

■ PAP, CHAP and MS-CHAP support

■ Callback support for dial-in and dial-out calls

Upgradeability

■ Flash memory for ﬁeld ﬁrmware updates

■ Firmware posted on 3Com’s Web site

■ Fully upgradeable to future 56K standards

Diagnostics

■ LED status display

■ Statistics display

Warranty

■ 3Com Corporation Limited Lifetime Warranty (refer to the end of this User

Guide for details).

Support for Internet Applications

Support for applications that use the User Datagram Protocol (UDP) and the

Transmission Control Protocol (TCP). The UDP protocol is used primarily by Internet

games.

Look for the latest list of Internet applications and games that are interoperable

with the LAN Modem at

http://www.3com.com/support/docs/lanmodem/.

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