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®

3C

OM

â

I

MPACT

ä

ISDN E

XTERNAL

D

IGITAL

M

ODEM

U

SER

G

UIDE

A member of the 3Com Impact product family

Part No. 09-0699-002

Published August 1995

3Com Corporation

■

5400 Bayfront Plaza

■

Santa Clara, California

■

95052-8145

Ó

3Com Corporation, 1995. All rights reserved. No part of this documentation may be 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 Unpublished rights reserved under the copyright laws of the United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.

The software described in this documentation is furnished under a license agreement included

with the product either as a separate document or on the software distribution diskette in a root

directory file named LICENSE.TXT. If you are unable to locate a copy, please contact 3Com and a

copy will be provided to you.

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

may not be registered in other countries.

3Com is a registered trademark of 3Com Corporation. Async-PPP, Impact, and QuickSelect are

trademarks of 3Com Corporation. 3ComFacts, Ask3Com, and NetFacts are service marks of 3Com

Corporation.

CompuServe is a registered trademark of CompuServe, Inc.

IBM, AT, and Power PC are trademarks of International Business Machines Corporation. Apple,

Macintosh, and Power Macintosh are trademarks of Apple Computer Corporation. UL is a

trademark of Underwriters Laboratories, Inc. Pentium is a trademark of Intel Corporation.

Microsoft, MS-DOS, and Windows are trademarks of Microsoft Corporation. Siemens is a trademark

of Siemens Artiengesellschaft. Northern Telecom is a trademark of Northern Telecom Limited.

AT&T is a trademark of American Telephone & Telegraph Company. Motorola is a trademark of

Motorola, Inc. TurboCom is a trademark of Bio-Engineering Research Laboratory. AdTran is a

trademark of AdTran, Inc. Delrina, WinComm, and WinFax are trademarks of Delrina Corporation.

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

holders.

Guide written by Anne Bailey. Edited by Nancy Kurahashi. Technical illustration by Tim Buckreus.

Production by Yvonne Sartain.

C

ONTENTS

A

BOUT

T

HIS

G

UIDE

Introduction i

How to Use This Guide i

Conventions ii

1

I

NTRODUCTION

3Com Impact Digital Modem Features 1-3

Data Capabilities 1-4

Voice Capabilities 1-4

Simultaneous Data and Voice Capabilities 1-4

Analog Modem Capabilities 1-5

3Com Impact Digital Modem Package Contents 1-5

Standard Package Contents 1-5

Additional Contents 1-5

ISDN Digital Line Configuration Requirements 1-6

Computer System Requirements 1-7

IBM PC or Compatible Requirements 1-8

Apple Macintosh Requirements 1-8

Cabling Requirements 1-9

2

I

NSTALLING

AND

C

ONFIGURING

THE

D

IGITAL

M

ODEM

Installing the 3Com Impact Digital Modem 2-3

Installing the Digital Modem in an IBM-compatible PC 2-3

Installing the Digital Modem in an Apple Macintosh Computer 2-4

Configuring the 3Com Impact Digital Modem 2-6

Configuration for IBM PC or Compatible Computer 2-7

Configuration for Apple Macintosh Computer 2-13

Placing and Receiving Calls 2-15

Placing ISDN Data Calls 2-15

Multilink PPP Calls With Dynamic Bandwidth Allocation 2-15

Placing Analog Modem Calls 2-17

Using Communications Software to Place Calls 2-17

Receiving Data Calls 2-17

Using the Phone Out Port 2-17

Placing Calls Using the Phone Out Port 2-18

Receiving Calls Using the Phone Out Port 2-18

Protocol Support 2-19

Async-Sync PPP Conversion 2-19

QuickSelect 2-19

3

T

ROUBLESHOOTING

Troubleshooting Tips 3-1

Downloading Firmware to Your External Digital Modem 3-5

A

AT C

OMMAND

S

ET

O

VERVIEW

B

AT C

OMMANDS

, R

EGISTERS

,

AND

R

ESULT

C

ODES

AT Command Set for the 3Com Impact

Digital Modem B-1

AT Command Set for Internal Analog Fax Modem B-4

Remote S Registers B-7

Digital Modem Result Codes B-10

C

T

ECHNICAL

S

UPPORT

On-line Technical Services C-1

3Com Bulletin Board Service C-1

World Wide Web Site C-2

Ask3Com on CompuServe C-2

3ComFacts Automated Fax Service C-2

Support from Your Network Supplier C-3

Support from 3Com C-4

Returning Products for Repair C-4

L

IMITED

W

ARRANTY

FCC C

LASS

B C

ERTIFICATION

S

TATEMENT

C

ANADIAN

N

OTICE

F

IGURES

1-1

Analog and Digital Network Access with the

3Com Impact Digital Modem 1-2

2-1

Back Panel Power Switch and Connectors 2-1

2-2

Front Panel LED Indicators 2-1

2-3

Configuration Dialog Box 2-8

T

ABLES

1

Text Conventions ii

2

Notice Icons ii

1-1

ISDN Ordering Information by Switch Type 1-7

1-2

Pin Descriptions 1-9

2-1

Front Panel LED Indicator Definitions 2-2

B-1

AT Command Set Summary B-1

B-2

AT Command Set Summary for the Internal Analog Modem B-4

B-3

Remote S Registers B-7

B-4

3Com Impact Digital Modem Result Codes B-10

A

BOUT

T

HIS

G

UIDE

Introduction

This guide describes how to install, operate, and

troubleshoot the 3Com

â

Impact

ä

ISDN External Digital

Modem, referred to throughout this guide as the 3Com

Impact digital modem.

If the information in the release notes shipped with your

product differs from the information in this guide, follow the

release notes. Be sure to read the README.TXT or Read Me

files on the applicable software utility diskette for the latest

product information.

How to Use This Guide

The following table shows where to find specific information

in this guide.

If you are looking for: Turn to:

General information about the 3Com Impact digital modem Chapter 1

Instructions for installing and operating the digital modem Chapter 2

Simple digital modem troubleshooting tips Chapter 3

Instructions for using the AT command line set Appendix A

Tabular summary of the AT command line set, registers,

and result codes

Appendix B

Information about 3Com’s technical support Appendix C

ii

A

BOUT

T

HIS

G

UIDE

Conventions

Table 1 and Table 2 list text and icon conventions that are

used throughout this guide:

Table 1

Text Conventions

Convention Description

Text represented as

screen

display

This typeface

is used to represent displays that appear

on your terminal screen, for example:

NetLogin:

Text represented as

commands

This typeface

is used to represent commands that you

enter, for example:

SETDefault !0 -IP NETaddr = 0.0.0.0

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

.

Table 2

Notice Icons

Icon Type Description

Information Note Information notes call attention to important features

or instructions.

Caution Cautions contain directions that you must follow to

avoid immediate system damage or loss of data.

Warning Warnings contain directions that you must follow for

your personal safety. Follow all instructions carefully.

1

I

NTRODUCTION

The Integrated Services Digital Network (ISDN) is a digital

communications standard for supporting voice, data, and

video applications through conventional telephone wires.

Specifically, ISDN is a method of connecting to the public

telephone network using digital technology. ISDN uses the

existing copper wire and public telephone network

infrastructure. All existing voice services provided by the

telephone companies are accessible using ISDN, and for the

first time, high-speed dial-up data can be provided

cost-effectively to the mass market.

Two electrical interfaces are defined as part of ISDN. The first

and less expensive is Basic Rate ISDN, or 2B+D. A Basic Rate

Interface (BRI) has two 56 or 64 Kbps (kilobits per second)

B (

B

earer) channels for user data, and one 16 Kbps signaling

D (

D

ata) channel, used for packet communications with the

public network and providing status and control information.

In most regions, the ISDN BRI is priced at 1.5 to 1.8 times the

monthly cost of an analog POTS (plain old telephone service)

telephone line. You may dial voice or data connections on

either or both of the B channels simultaneously. Calls placed

from an ISDN line may connect to remote sites that have

analog POTS, Switched 56, ISDN BRI, or T1 telephone lines.

There is full compatibility with existing services, and no need

for ISDN BRI on both ends.

The other electrical interface, which is somewhat more

expensive, is the ISDN Primary Rate Interface (PRI). PRI is

based on the more expensive and higher-speed T1 networks

that are typically deployed at larger sites. PRI consists of 23

B channels and one 64 Kbps D channel, providing large

businesses with a greater degree of flexibility.

1-2

C

HAPTER

1: I

NTRODUCTION

The 3Com Impact ISDN External Digital Modem (referred to as

the 3Com Impact digital modem throughout this guide) is an

external, stand-alone ISDN Basic Rate digital modem for

connection with digital telephone services from local telephone

companies in North America. It is designed for users who

require high-speed access to the Internet, on-line information

services, or their corporate local area network (LAN). A typical

3Com Impact digital modem application is shown in Figure 1-1.

Figure 1-1

Analog and Digital Network Access with the 3Com Impact

Digital Modem

Four models of the 3Com Impact digital modem are sold in

the U.S. and Canada:

■

3C871 is the IBM

â

or IBM-compatible PC external digital

modem product.

■

3C872 is the IBM

or IBM-compatible PC external digital

modem product with an internal 14.4 Kbps analog fax

modem.

■

3C876 is the Apple

â

Macintosh

â

external digital modem

product.

■

3C877 is the Apple Macintosh external digital modem

product with an internal 14.4 Kbps analog fax modem.

®

3

Com

Impact

™

D-Channel

B-1

B-2

Test

Power

3Com Impact

ISDN External

Digital Modem Internet

or

on-line service

Analog or ISDN line

Analog or ISDN line

Public telephone

network

Corporate

LAN

ISDN line

3Com Impact Digital Modem Features

1-3

The 3Com Impact digital modem can be connected to any

compatible UL

â

-listed IBM AT

â

-compatible or Apple Macintosh

personal computer that includes instructions for the installation

of hardware and software options to serial ports.

3Com Impact Digital Modem Features

The 3Com Impact digital modem provides the following:

■

A complete digital network termination (Basic Rate ISDN NT1).

■

Full ISDN signaling support of National ISDN and

pre-National ISDN service offerings.

■

An asynchronous RS-232-C data port for connectivity to IBM

or compatible PC and Apple Macintosh serial ports at rates of

up to 115.2 Kbps.

■

AT command set dialing.

■

Interoperability support through standard protocols like

Point-to-Point Protocol (PPP) and V.120. (V.120 is a rate

adaption scheme to convert transmission rates from a range

of 50 bps to 19.2 Kbps to the B channel 64 Kbps rate.)

■

Multilink PPP support, which allows the two B channels to be

virtually linked, thereby allowing a maximum digital

connection of 128 Kbps.

■

Dynamic bandwidth allocation (DBA), which allows you to

place a voice call while a Multilink PPP call is active.

■

Internal 14.4

Kbps analog fax modem (V.32

bis

compliant) for

connection to non-ISDN fax machines and modems (applies

to 3C872 and 3C877 models only).

■

An analog voice port for attaching analog telephones,

answering devices, and fax machines to the ISDN line.

■

A graphical user interface for digital modem configuration.

■A comprehensive diagnostic test and LED status display.

■One-year limited warranty within the “Other Hardware

Products” category of the 3Com Limited Warranty at the end

of this guide.

1-4 CHAPTER 1: INTRODUCTION

Data Capabilities

The 3Com Impact digital modem allows transmission of

asynchronous data at speeds of up to 115.2 Kbps over digital

ISDN connections with the highest reliability and error-free

performance possible. With Multilink PPP, a digital connection

of up to 128 Kbps can be established by aggregating the two

56 Kbps or 64 Kbps ISDN B channels. Note that the COM port

speed of your PC limits the maximum data transmission rate to

no more than 115.2 Kbps.

ISDN technology reduces call setup times by more than 50%

compared to V. fast/V.34 analog modem setup times,

reducing the time it takes to establish a connection to under

three seconds.

This high-speed performance allows you to do the following:

■Dial up the Internet at high data rates

■Access your office’s LAN

■Access and download graphics, software, and data files more

quickly

Voice Capabilities

The 3Com Impact digital modem’s Phone Out port allows the

use of existing analog telephone equipment (touch-tone

telephones, cordless telephones, and fax and answering

machines) to place and receive calls over the ISDN line. When

you connect to another ISDN line, setup times are reduced,

and voice quality is excellent.

Simultaneous Data and Voice Capabilities

The 3Com Impact digital modem quickly processes data and

voice calls simultaneously. For example, you can send a fax or

place a voice telephone call while maintaining a high-speed

connection to the office LAN; you can also receive a voice

telephone call while you are connected to the Internet.

3Com Impact Digital Modem Package Contents 1-5

Analog Modem Capabilities

The 3Com Impact digital modem (models 3C872 and 3C877)

includes an integrated V.32bis analog modem for data or fax

transmissions of up to 14.4 Kbps over the ISDN line. V.42bis

data compression boosts analog modem throughput to up

to 57.6 Kbps.

3Com Impact Digital Modem Package Contents

3Com Impact digital modems are available in Macintosh and PC

versions, with or without a built-in V.32bis analog fax modem.

Standard Package Contents

The following list describes the package contents common

to models 3C871, 3C872, 3C876, and 3C877. Refer to the

section “Additional Contents” for any additional items that

are specific to a particular model.

■One 3Com Impact ISDN digital modem

■One power cable with an ac wall transformer

■One serial cable

■One RJ -45/RJ -11 ISDN telephone cable

■One 3.5" installation diskette

■3Com Impact ISDN External Digital Modem User Guide

■3Com Impact ISDN External Digital Modem Quick Start

Instructions

Additional Contents

Model 3C871

■One copy of TurboComä Windowsä software

■One DB-9-to-DB-25 serial connection adapter

1-6 CHAPTER 1: INTRODUCTION

Model 3C872

■One copy of TurboCom Windows software

■One copy of Delrinaâ WinCommä Lite and WinFaxâ Lite

communications software

■One DB-9-to-DB-25 serial connection adapter

ISDN Digital Line Configuration Requirements

The 3Com Impact digital modem requires an ISDN digital

telephone line that is properly configured for use with the

digital modem.

3Com has determined the optimal ISDN line configurations

for the 3Com Impact digital modem and has provided that

configuration data to many telephone companies.

To simplify the ordering process for an ISDN digital line, use

the following simplified ISDN ordering code:

3ComA * J6

If your digital modem has an internal analog fax modem

(Models 3C872 and 3C877), then two directory numbers

(telephone numbers) will be required to allow a voice call

and a fax modem call to occur at the same time. When you

tell the telephone company the ISDN ordering code

(3ComA * J6), let the representative know that you will need

two directory numbers.

If your telephone company does not support simplified ISDN

ordering codes, refer to Table 1-1 for ISDN ordering

information.

Present this ordering information to the ISDN line installer or

telephone company service representative in your area. Also,

make sure that your local telephone company installer

provides an RJ-11 or RJ-45 connector for your ISDN line.

Computer System Requirements 1-7

Computer System Requirements

* Two directory numbers are required for Models 3C872 and 3C877. This allows a voice call and a

call using the internal analog fax modem to occur at the same time.

Connect the model 3C871 or 3C872 3Com Impact digital

modem to an IBM-compatible computer. Connect the model

3C876 or 3C877 3Com Impact digital modem to an Apple

Macintosh computer. Connect the digital modem to a

computer that meets UL standards in the United States or is

certified to CSA standards in Canada.

Table 1-1 ISDN Ordering Information by Switch Type

ISDN Switch Type

ISDN Line

Configuration

Parameter

AT&Tâ 5ESS

Custom

AT&T 5ESS

National

ISDN-1

Northern

Telecomâ

DMS100

National

ISDN-1

Siemensâ

EWSD

National

ISDN-1

Line Code 2B1Q (no NT1

required)

2B1Q (no NT1

required)

2B1Q (no NT1

required)

2B1Q (no NT1

required)

Directory

Numbers

1*1*2 1*

Channels 2B alternate

circuit-switched

data and voice

2B alternate

circuit-switched

data and voice

2B alternate

circuit-switched

data and voice

2B alternate

circuit-switched

data and voice

Terminal Type A with

Point-to-Point

A with

Point-to-Point

Functional PVC 2 Functional

TEI Dynamic Dynamic Dynamic Dynamic

Call

Appearances

Idle Idle — —

Supplemental

Voice Features

None None None None

EKTS Features No No No No

D Channel

Packet

No No No No

B Channel

Packet

No No No No

1-8 CHAPTER 1: INTRODUCTION

IBM PC or Compatible Requirements

An IBM-compatible PC must have the following:

■A 386, 486, or Pentiumâ processor

■An available serial communications port

For sustained performance at higher data rates (57.6 Kbps

and 115.2 Kbps), it is recommended that your IBM or IBM-

compatible PC serial COM port be equipped with a 16C550

UART (universal asynchronous receiver/transmitter). To

determine what UART is installed in your PC, run the

Microsoftâ Diagnostic Program (msd) from the DOS prompt.

In addition, for reliable high-speed serial port performance in

the Microsoft Windows environment, a TurboComä driver for

Windows, which replaces the standard Microsoft Windows

COM driver, is included with the 3Com Impact digital modem.

■MS-DOSâ or IBM PC DOS 3.1 or later operating system

■640 Kilobytes of conventional memory

■Microsoft Windows 3.1 or later (optional)

■A hard disk drive with 1 MB of free space

Apple Macintosh Requirements

An Apple Macintosh computer must be a Macintosh Plus or

later model. It must also have the following:

■An available serial communications port

The highest possible serial port data rate with most

Macintosh computers is 57.6 Kbps. Some later Macintosh

models (AV and Power Macintoshä) have data rates of up to

115.2 Kbps. 3Com recommends that you use the 8-pin serial

communications port on your Macintosh.

■System 7 or later operating system

■A hard disk drive with 1 MB of free space

Cabling Requirements 1-9

Cabling Requirements

Cables to connect the 3Com Impact digital modem to your

computer are provided. For IBM or IBM-compatible PCs with

a 25-pin serial port, a DB-9–to–DB-25 connection adapter is

included with the digital modem.

The asynchronous RS-232-C port on the digital modem,

labeled Computer, is a standard DB-9 female connector. The

digital modem asynchronous port pin assignments, shown in

Table 1-2, conform to standard definitions for data

communications equipment (DCE).

Table 1-2 Pin Descriptions

Pin # Pin Name Signal Direction

1Carrier Detect (DCD) From digital modem

2 Receive Data (RD) From digital modem

3 Transmit Data (TD) To digital modem

4 Data Terminal Ready

(DTR)

To digital modem

5 Signal Ground (GND) —

6 Data Set Ready (DSR) From digital modem

7 Request to Send (RTS) To digital modem

8 Clear to Send (CTS) From digital modem

9 Ring Indicator (RI) From digital modem

2INSTALLING AND

CONFIGURING

THE DIGITAL MODEM

This chapter describes installation and configuration of the

3Com Impact digital modem. In combination with the

instructions given in this chapter, follow the instructions

given in the appropriate PC or Macintosh computer user

guide. Refer to Figure 2-1 and Figure 2-2, showing the digital

modem back and front panels, during installation and

configuration. If you encounter difficulties after installation,

refer to Chapter 3, “Troubleshooting.”

Figure 2-1 Back Panel Power Switch and Connectors

The LED status display, shown in Figure 2-2, consists of five

front panel LEDs that are described in Table 2-1.

Figure 2-2 Front Panel LED Indicators

Power 12V AC RS232D Wall

ISDN BRI-U ONLY

RS232D

D-Channel

B-1

B-2

Test

Power

®3ComImpact™

2-2 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

Table 2-1 Front Panel LED Indicator Definitions

LED Color Description

Power Yellow Power Indicator. Lit when power is on and remains lit as long

as power is available from the ac wall transformer plugged into

the electrical outlet.

Test Yellow Self-Test/Status. Flashes when the digital modem is

executing its power-up self-test or a user-initiated reset. If the

results of the self-test or reset are normal, the LED goes off. If

the result of the self-test is abnormal and a fault is detected,

the LED remains lit but does not flash.

D-Channel Yellow D Channel/Status. Provides a quick indication of the ISDN

physical network interface and D channel status. If the physical

ISDN interface is not synchronized or is disconnected, this LED

remains lit.

If the physical interface establishes synchronization and the

ISDN D channel signaling procedures are not properly

established, the LED flashes.

Once the physical and D channel signaling are synchronized,

the LED goes off.

If any physical loss of framing occurs, the LED lights; if there is

a loss of D channel signaling, the LED flashes.

B-1 Yellow

or

green

B-1 Channel Indicator. Indicates the activity state of the B-1

channel of the ISDN interface. Green indicates a

circuit-switched data call. Yellow indicates a circuit-switched

voice call. If a call is in a dialing state, the LED flashes. When a

call enters the active state, the appropriate LED color stays lit.

When the call is disconnected, the LED goes off.

B-2 Yellow

or

green

B-2 Channel Indicator. Indicates the activity state of the B-2

channel of the ISDN interface. Green indicates a

circuit-switched data call. Yellow indicates a circuit-switched

voice call. If a call is in a dialing state, the LED flashes. When a

call enters the active state, the appropriate LED color stays lit.

When the call is disconnected, the LED goes off.

Installing the 3Com Impact Digital Modem 2-3

Installing the 3Com Impact Digital Modem

This installation procedure assumes that you are familiar

with IBM and IBM-compatible or Apple Macintosh

computers. If you are not, refer to the user guide that

accompanied your computer for instructions on hardware

installation and operating system commands.

Installing the Digital Modem in an IBM-compatible PC

To install the 3Com Impact digital modem model 3C870 or

3C872 in an IBM or IBM-compatible computer:

1Turn off the computer.

2Ensure that the 3Com Impact digital modem power switch

is in the Off position.

3Insert the 9-pin male end of the 3Com Impact digital

modem-to-PC serial signal cable into the connector

labeled Computer on the digital modem’s back panel and

tighten the connector screws.

4Connect the other end of the 3Com Impact digital

modem-to-PC serial signal cable to a serial

communications (COM) port on the back of your PC and

tighten the connector screws.

Most COM port connectors are labeled COM, SERIAL, or

RS-232-C. On an IBM AT PC and most laptops or notebooks,

connect the cable to a 9-pin COM port connector.

5Connect the 3Com Impact digital modem power cable to the

connector marked 12V AC on the back panel of the digital

modem.

See Figure 2-1 for the location of the 12V AC connector on

the digital modem’s back panel.

6Plug the transformer end of the power cable into a

standard 117V ac wall outlet.

2-4 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

7Connect the RJ-45 (8-pin) connector end of the

RJ-45/RJ-11 ISDN cable to the RJ-45 connector labeled

Wall on the digital modem’s back panel.

See Figure 2-1 for the location of the RJ-45 connector on the

digital modem’s back panel.

8Connect the RJ-11 (6-pin) connector end of the

RJ-45/RJ-11 ISDN cable to the RJ-11 ISDN wall jack.

CAUTION: The 3Com Impact digital modem is designed

to operate with Basic Rate ISDN 2B1Q U Interface network

terminations. An internal Network Termination device

(NT1) is built into the digital modem. Do not connect the

3Com Impact digital modem ISDN port to a standard

analog telephone jack or to an external NT1 device. Make

sure that it is connected to the ISDN jack.

9Turn on the 3Com Impact digital modem by toggling the

power switch on the back panel to the On position.

See Figure 2-1 for the location of the power switch on the

digital modem’s back panel. The indicator LEDs on the front

panel (see Figure 2-2) flash momentarily as the unit

undergoes a power-up self-test diagnostic.

10 Turn on the computer’s power switch.

11 Go to the section “Configuration for IBM PC or

Compatible Computer” later in this chapter to configure

the 3Com Impact digital modem.

Installing the Digital Modem in an Apple Macintosh

Computer

To install the 3Com Impact digital modem model 3C875 or

3C877 in an Apple Macintosh computer:

1Turn off the computer.

2Ensure that the 3Com Impact digital modem power switch

is in the Off position.

Installing the 3Com Impact Digital Modem 2-5

3Insert the 9-pin male end of the 3Com Impact digital

modem-to-Macintosh serial signal cable into the

connector labeled Computer on the digital modem’s back

panel and tighten the connector screws.

4Connect the other end of the 3Com Impact digital

modem-to-Macintosh serial signal cable to the serial

communications port on the back of the Macintosh.

The serial communications port is the mini-DIN, 8-pin serial

port connector, indicated on the Macintosh connector panel

by the telephone handset imprint.

5Connect the 3Com Impact digital modem power cable to

the connector marked 12V AC on the back panel of the

digital modem.

See Figure 2-1 for the location of the 12V AC connector on

the digital modem’s back panel.

6Plug the transformer end of the power cable into a

standard 117V ac wall outlet.

7Connect the RJ-45 (8-pin) connector end of the

RJ-45/RJ-11 ISDN cable to the RJ-45 connector labeled

Wall on the digital modem’s back panel.

See Figure 2-1 for the location of the RJ-45 connector on the

digital modem’s back panel.

8Connect the RJ-11 (6-pin) connector end of the

RJ-45/RJ-11 ISDN cable to the RJ-11 ISDN wall jack.

CAUTION: The 3Com Impact digital modem is designed

to operate with Basic Rate ISDN 2B1Q U Interface network

terminations. An internal Network Termination device

(NT1) is built into the digital modem. Do not connect the

3Com Impact digital modem ISDN port to a standard

analog telephone jack or to an external NT1 device. Make

sure that it is connected to the ISDN jack.

2-6 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

9Turn on the 3Com Impact digital modem by toggling the

power switch on the back panel to the On position.

See Figure 2-1 for the location of the power switch on the

digital modem’s back panel. The indicator LEDs on the front

panel (see Figure 2-2) flash momentarily as the unit

undergoes a power-up self-test diagnostic.

10 Turn on the computer’s power switch and restart.

11 Go to the section “Configuration for Apple Macintosh

Computer” later in this chapter to configure the 3Com

Impact digital modem.

Configuring the 3Com Impact Digital Modem

The 3Com Impact digital modem requires the five essential

configuration parameters below before it can operate

properly on an ISDN line. Before configuring the digital

modem, make sure you have this information readily

available. These five parameters are provided to you at the

time of installation of your ISDN line by the telephone

company installer.

■ISDN Switch Type

■Phone #1 (local directory telephone number)

■SPID #1 (Service Profile Identifier)

■Phone #2 (if required by the telephone company)

■SPID #2 (if required by the telephone company)

Each of these items is stored in special S registers within the

digital modem. These S registers are set by issuing ATSxx=

commands to the digital modem. The Impact digital modem

software will automatically issue the AT commands to set the

S registers as part of the configuration process.

The following three sections describe how to configure the

3Com Impact digital modem using the Windows, DOS, or

Macintosh operating systems, respectively.

Configuring the 3Com Impact Digital Modem 2-7

After you configure the digital modem and verify that it is

working properly, you should install the TurboCom software.

Refer to the installation instructions that came with the

TurboCom software. This software is required only for

IBM PC or compatible computers running Windows 3.X.

Configuration for IBM PC or Compatible Computer

You can configure the 3Com Impact external digital modem

for an IBM PC or compatible using either the Windows-based

installation program or the MS-DOSâ–based installation program.

Configuration Using Windows

To configure the digital modem for an IBM PC or compatible

computer using Windows:

1Insert the 3Com Impact DOS & Windows Installation

Diagnostic Utilities diskette into an available diskette drive.

2Select Run from the File menu. In the Run dialog box, type:

a:setup

The check box labeled Run Minimized should be left

unchecked.

3Click OK.

The installation process begins copying the configuration

program to the hard disk. A message box provides the status

of the installation and indicates when it is complete.

4Double-click the 3Com Impact icon to access the 3Com

Impact Configuration dialog box.

COM1 is the default COM port.

■If the digital modem is connected to COM1, the 3Com

Impact Configuration dialog box appears, as shown in

Figure 2-3. Go on to step 5.

■If the digital modem is not connected to COM1, the COM

Port Provisioning dialog box appears. Choose the

COM port to which the digital modem is connected.

2-8 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

Click Connect. The 3Com Impact Configuration dialog

box appears, as shown in Figure 2-3.

Figure 2-3 Configuration Dialog Box

A status bar below the Help, Tools, Configure, and Exit

buttons provides the following ISDN status information:

■Layer 1 status

■Service Profile Identifier (SPID) for telephone numbers 1 and 2

■Terminal Endpoint Identifiers (TEI) 1 and 2 (for information

purposes only)

A message bar at the bottom of the dialog box provides help

for completing the fields. If you click in a field, the message bar

tells you what information to enter in the field. The message bar

also provides status information about the digital modem. If the

digital modem is disconnected from the ISDN telephone line,

for example, a message indicates this condition.

The right side of the dialog box shows the digital modem

software version, along with any installed options (such as

Multilink PPP or internal analog fax modem).

Configuring the 3Com Impact Digital Modem 2-9

5Select the type of switch, as specified by your telephone

company, from the Telephone Company Switch

drop-down list box.

6Click in the Telephone Number field in the Number 1 area

and enter the telephone number to which your digital

modem is connected.

7Click in the Service Profile Identifier (SPID) field and enter

the corresponding SPID for the telephone number you

entered in the previous step.

You should have received this SPID from your telephone

company.

CAUTION: If the ISDN line has been configured with only one

telephone number (Point-to-Point), do not include the SPID.

8Specify which device should receive the calls coming to

Telephone Number 1.

You can select Phone Port or Internal Fax/Modem. If your

model has the internal analog fax modem installed (Models

3C872 and 3C877), you can select both.

If both boxes are checked, the internal analog fax modem

and the phone will both ring, enabling you to answer using

either device.

9If you have a second telephone number associated with

your ISDN telephone line (some telephone companies

require two), enter the number and corresponding SPID in

the appropriate fields in the Number 2 area.

10 Specify which device should receive the calls coming to

Telephone Number 2.

11 Click the Configure button to download the parameters

listed in steps 5 through 10 to your digital modem’s

S registers.

2-10 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

12 If you have changed the Telephone Company Switch type,

you must reset the digital modem by turning the power

switch off and then on.

13 Verify the configuration.

Check the status bar (located beneath the Help, Tools,

Configure, and Exit buttons of the Configuration dialog box)

to verify correct configuration. If the parameters were

configured accurately and the digital modem is ready to

send and receive calls, the status bar fields will appear as

shown below. Note that the TEI number(s) are not configured

by the user. The TEI number is provided by the telephone

company for informational purposes only.

■Layer 1: UP

■SPID 1: Init

■TEI 1: Number from 0 to 127

■SPID 2: Init (if required)

■TEI 2: Number from 0 to 127 (if required)

14 Click Exit to leave the utility.

This completes the configuration procedure.

15 Install the TurboCom software.

Refer to the installation instructions that came with the

TurboCom software.

After the TurboCom software is installed, proceed to the

“Placing and Receiving Calls” section.

Configuration Using DOS

To configure the digital modem for an IBM PC or compatible

computer using DOS:

1Create a directory on the hard drive, insert the 3Com

Impact DOS & Windows Installation Diagnostic Utilities

diskette into the PC’s diskette drive, and copy all the files

from the utility diskette to the hard drive.

Configuring the 3Com Impact Digital Modem 2-11

Copy the files to a new DOS directory. For example, to create a

directory dddd on your C drive at the C:\> DOS prompt, type:

md c:\dddd

To copy all files from the diskette to a directory \dddd at the

A:\> DOS prompt, type:

copy a:*.* c:\dddd

2Execute INSTALL from the hard drive.

At the C:\> DOS prompt, type:

INSTALL

The configuration program launches and presents the

Port Settings screen. To move the cursor around the screen,

use the [Up Arrow] and [Down Arrow] keys. To select a

parameter, use the [Space Bar].

3Use the [Space Bar] to select the digital modem’s

COM port and COM port data rate.

This sets the speed of communication between the

3Com Impact digital modem and the computer during

configuration.

When you select the port, the standard interrupt (IRQ)

associated with that port is automatically chosen. Select the

COM port data rate based on the data rate required by the

destination digital modem and the maximum data rate

supported by your computer’s COM port.

The program does not allow you to select a data rate that

exceeds the speed of your COM port.

4Press [F10] to connect to the 3Com Impact digital modem

via the chosen COM port.

The Configuration screen will appear.

5In the Phone #1 field, enter the telephone number to

which your digital modem is connected.

2-12 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

6Enter the corresponding Service Profile Identifier (SPID) in

the SPID #1 field for the telephone number you entered in

the previous step.

You should have received this SPID from your telephone

company.

CAUTION: If the ISDN line has been configured with only one

telephone number (Point-to-Point), do not include the SPID.

7Specify which device should receive the calls coming to

Phone #1.

You can select Phone Port or Internal Fax/Modem. If your

model has the internal analog fax modem (Models 3C872

and 3C877), you can select both. The Phone Port and Internal

Fax/Modem check boxes associated with Phone #1 appear

to the right of Phone #1.

If both boxes are checked, the internal analog fax modem

and the phone will both ring, enabling you to answer using

either device.

8If you have a second telephone number associated with

your ISDN telephone line (some telephone companies

require two), enter the number and corresponding SPID in

the Phone #2 and SPID #2 fields.

9Specify which device should receive the calls coming to

Phone #2.

10 Confirm that the parameters listed in steps 5 through 9

are correct.

When these parameters are updated, the information is read

back to the screen. Check to see that the values have been

correctly entered.

11 Press [F10] to update the information in the 3Com Impact

digital modem.

Configuring the 3Com Impact Digital Modem 2-13

12 Reset the digital modem by turning the power switch off

and then on again.

If the parameters match those registered at the telephone

company ISDN switch, the D channel LED lights for a few

minutes, flashes for several seconds, and then turns off. If the

LED continues to flash or remains lit, see Chapter 3,

“Troubleshooting.”

13 Press [Esc] to return to the main menu.

Once in the main menu, exit the program.

14 Go to the section “Placing and Receiving Calls” to place

your first call.

Configuration for Apple Macintosh Computer

To configure the digital modem for an Apple Macintosh

computer:

1Insert the 3Com Impact Installer Diagnostic Utilities

software utility diskette into the diskette drive and copy

the files by selecting them and dragging them to the

hard drive icon.

The Macintosh operating system automatically places the

files in the appropriate folders.

2Open the 3Com Impact Mac folder and double-click the

3Com Impact Installer program icon to launch it.

The utility program presents the Port Settings screen. To

move the cursor around the screen, use the [Tab] key. Select

the Modem port and click OK. The Utility dialog box appears.

3In the Phone Number 1 field, enter the telephone number

to which your digital modem is connected.

4Enter the corresponding Service Profile Identifier (SPID) in

the SPID field for the telephone number you entered in

the previous step.

2-14 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

You should have received this SPID from your telephone

company.

CAUTION: If the ISDN line has been configured with only one

telephone number (Point-to-Point), do not include the SPID.

5Specify which device should receive the calls coming to

Phone Number 1.

You can select Phone Port or Internal Fax/Modem. If your model

has the internal analog fax modem (Models 3C872 and 3C877),

you can select both.

If both boxes are checked, the internal analog fax modem

and the phone will both ring, enabling you to answer using

either device.

6If you have a second telephone number associated with

your ISDN telephone line (some telephone companies

require two), enter the number and corresponding SPID in

the Phone Number 2 and SPID Number 2 fields.

7Specify which device should receive the calls coming to

Phone Number 2.

8Confirm that the parameters listed in steps 3 through 7

are correct.

9Click the Update Configuration button to update this

information to the 3Com Impact digital modem.

10 Reset the digital modem by turning the power switch off

and then on again.

If the parameters match those registered at the telephone

company ISDN switch, the D channel LED lights for a few

minutes, flashes for several seconds, and then turns off. If the

LED continues to flash or remains lit, see Chapter 3,

“Troubleshooting.”

11 Go to the section “Placing and Receiving Calls” to place

your first call.

Placing and Receiving Calls 2-15

Placing and Receiving Calls

This section illustrates how to place and receive a variety of

calls with your 3Com Impact digital modem. The digital

modem uses AT commands and S registers for call

management. See Appendix A, “AT Command Set

Overview,” for instructions on use of the AT command set,

and Appendix B, “AT Commands, Registers, and Result

Codes,” for a tabular summary of the AT command lines.

Placing ISDN Data Calls

When you need to place a call from your PC or Macintosh,

the 3Com Impact digital modem recognizes the AT

command ATD to dial a digital ISDN data call. Depending on

the setting of register S60, 56 Kbps (default) or 64 Kbps

B channel transmission speeds are used. Correct examples of

outgoing circuit-switched digital modem commands with

dial strings are:

AT D 1 908 555 7891

ATD19085555555

Multilink PPP Calls With Dynamic Bandwidth Allocation

The 3Com Impact digital modem supports Multilink PPP,

which allows the two B channels to be virtually linked, thereby

allowing a maximum digital connection of 128 Kbps. Note

that both your service and the one that you are dialing into

must support Multilink PPP, or the virtual linking will not

occur. Multilink PPP is enabled by default.

Multilink configuration is facilitated through registers S80,

S81, S82, and S83. Additionally, dynamic bandwidth

allocation (DBA) in multilink mode is configured in

register S70. Register S80 enables (the default) or disables

Multilink PPP operation.

2-16 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

By default, the 3Com Impact digital modem dials the same

number for both Multilink PPP channels. If the destination to

which the digital modem is dialing to establish a second

Multilink PPP channel requires a different telephone number,

then this second telephone number is stored in register S81.

By default, this register is empty. It must be configured

before you establish each Multilink PPP call. If the

Multilink PPP destination is a single telephone number for

both channels, then be sure to clear register S81 by sending

the command ATS81=<blank> to the digital modem.

Some Multilink PPP implementations require the use of a

Multilink PPP option called the Multilink Endpoint Identifier.

This option is configured in registers S82 and S83.

Register S82 stores the Multilink Endpoint Identifier Class

value. Valid classes are listed in Appendix B, “AT Commands,

Registers, and Result Codes.” Register S83 stores the actual

Multilink Endpoint Identifier. Note that this option is not

required in most cases, so these registers typically do not

have to be changed. If the Multilink Endpoint Identifier is

required, these values will be provided by your system

administrator or Internet service provider.

When dynamic bandwidth allocation is enabled (by default),

you can place a voice call from a device that is attached to

the Phone Out port while a Multilink PPP call is active. When

you lift the telephone handset to place a voice call, the

digital modem automatically removes one of the Multilink

PPP connections and uses it for the voice call. Once the voice

call ends, the digital modem automatically reestablishes that

channel for Multilink PPP operation.

There may be cost implications due to the use of two

B channels for Multilink PPP. Check with your service

providers, such as the telephone company, Internet access

provider, or on-line service provider.

Using the Phone Out Port 2-17

Placing Analog Modem Calls

To place a call from your PC or Macintosh using the optional

V.32bis 14.4 Kbps internal analog fax modem (included with

models 3C872 and 3C877), use the AT command ATDT (for

connection to an analog modem using touch-tone dialing) or

ATDP (for connection to an analog modem using pulse dialing).

Using Communications Software to Place Calls

If you are using standard communications software, select a

Hayes-compatible modem configuration and dial out

through the 3Com Impact digital modem. Refer to your

communications software documentation for more details.

Receiving Data Calls

Incoming circuit-switched data calls from other

3Com Impact digital modems or from ISDN devices and

Sw56 equipment may be received by the digital modem.

If auto answer is disabled (the default) in register S0, a RING

message is delivered to the Computer port upon reception of

an incoming data call to the digital modem. The command AT

A answers the incoming data call. A CONNECT message is then

delivered to the Computer port upon successful connection.

If auto answer is enabled, the call is automatically answered

and a CONNECT message, indicating the speed of the

connection, is delivered to the Computer port.

Using the Phone Out Port

If you have analog touch-tone telephones, answering

machines, fax machines, external analog modems, or other

analog telephone devices, connect them to the 3Com Impact

digital modem’s RJ-11 modular jack labeled Phone Out on

the digital modem’s back panel (see Figure 2-1).

The 3Com Impact digital modem does not support pulse

dialing (rotary) telephones.

2-18 CHAPTER 2: INSTALLING AND CONFIGURING THE DIGITAL MODEM

CAUTION: The 3Com Impact digital modem is designed to

operate with telephones that are compatible with the original

AT&T 2500 touch-tone telephone standard. 3Com guarantees

proper operation of up to three compatible touch-tone devices

on the Phone Out port. The digital modem is designed to

provide power and ringing for these three devices on up to 100

feet of AWG 26 or heavier AWG wiring. Although the digital

modem may function satisfactorily at longer cable distances

with more than two attached telephones, proper operation at

longer cable distances is not guaranteed in all situations.

Specialized telephone equipment, most notably speaker

phones that draw significantly larger amounts of power, may

not work at all on the digital modem’s Phone Out port. These

devices do not conform to the loop current (power)

specification of the 2500 touch-tone telephone standard, and

their operation is not guaranteed.

Placing Calls Using the Phone Out Port

To place an outgoing call, simply take the telephone

handset or external fax machine off the hook, wait for a dial

tone, and dial the destination telephone number.

Receiving Calls Using the Phone Out Port

lncoming calls to the telephone number assigned to the

Phone Out port ring at the Phone Out port unless you are

busy on another Phone Out port call. If the port is busy, the

incoming call is automatically disconnected.

If you have a digital modem with an internal analog fax

modem (models 3C872 and 3C877) you can have calls routed

to the internal analog fax modem when the Phone Out port

is busy. To do this, the digital modem must be configured to

allow a call to be routed to both the Phone Out port and the

internal analog fax modem, as described in the section

“Configuring the 3Com Impact Digital Modem.”

Protocol Support 2-19

Protocol Support

Async-Sync PPP Conversion

One of the most unique and powerful features of the

3Com Impact digital modem is its ability to convert

asynchronous Point-to-Point Protocol (PPP) into synchronous

(HDLC-based) PPP that can be transported in ISDN

B channels to communications servers and routers that have

integrated ISDN Basic Rate (BRI), Primary Rate (PRI), or

T1 access lines.

A wide variety of software and internetworking products has

been tested for interoperability with the 3Com Impact

digital modem’s Async-Sync PPPä conversion software.

QuickSelect

The 3Com Impact digital modem supports V.120 and

Async-Sync PPP conversion. The digital modem uses a

technique called QuickSelectä so that you do not have to

manually select the proper protocol for each ISDN call. With

QuickSelect enabled (the default), the digital modem

automatically detects and uses the required protocol.

3TROUBLESHOOTING

This chapter explains how to isolate and solve simple

problems encountered with the 3Com Impact digital

modem. Problems may stem from incorrect option settings

or improper installation. Follow the steps outlined in this

chapter.

There are no user-serviceable parts inside your 3Com Impact

digital modem. Unauthorized opening of the unit will void

the warranty.

Troubleshooting Tips

Before you call 3Com’s technical support organization for

assistance, check the following:

1The power supply is connected and the power LED is on.

2Turn the 3Com Impact digital modem power switch off

and then on again several times and observe the Test LED.

During power-up self-test, the Test LED flashes.

■If the Test LED flashes and remains on for more than a few

minutes, there is an internal failure. Notify your reseller that

the 3Com Impact digital modem has failed the self-test, and

order a replacement.

■If the LED goes off after the test has been completed, the

test has been successful.

3Verify that the ISDN cable is connected to the digital

modem, and make sure it is connected to the ISDN wall

jack.

3-2 CHAPTER 3: TROUBLESHOOTING

The 3Com Impact digital modem will not operate if

connected to an analog telephone wall jack. Make sure that

the digital modem is connected directly into the ISDN wall

outlet without connection to any intermediate telephone

equipment (an NT1 device is not required with this digital

modem).

4Make sure that the cables provided by 3Com or a 3Com

authorized reseller are in good condition and show no

evidence of wear or other physical damage.

If damage is apparent after close inspection, contact your

reseller for replacement cables.

5Monitor the status of the D channel LED.

■If you are connected to a live digital ISDN line, the

D channel LED remains lit for up to a few minutes after

the self-test but then begins to flash.

When the D channel LED flashes, it indicates that the

ISDN signal is present.

When the D channel LED goes out, it indicates that a

valid communication channel has been established and

calls may be attempted by the user.

■If the D channel LED remains lit after more than a few

minutes, it is likely that there is a poor physical

connection to the local telephone company.

This fault can be caused by a damaged cable, a broken

wire, a damaged connector, a nonstandard U interface

(proprietary AMI line coding), or a problem within the

telephone company network. If the telephone wires at

your site appear to be satisfactory, call your local

telephone company for repair of telephone company

equipment and troubleshooting assistance.

■If the D channel LED flashes for more than a few minutes

without going out, there is probably a mismatch between

the settings of the ISDN line and the 3Com Impact digital

modem configuration.

Troubleshooting Tips 3-3

Check the Service Profile Identifier (SPID) entry and the

Phone# information in the digital modem software

configuration utility.

If you have verified once again that your SPID and Phone#

parameters are entered properly and the D channel LED

continues to flash without going out, call your telephone

company, verify that you have been given the correct SPID

and Phone# information, and ask whether the ISDN line is

Point-to-Point. If the ISDN line is Point-to-Point, be sure not

to include the SPID in the configuration.

Also verify that the telephone company has configured

the ISDN line properly for the 3Com Impact digital

modem product (see Table 1-1). If the D channel LED

does not go out after these verifications, call your reseller

for line configuration and troubleshooting assistance.

■If the D channel LED goes out, the digital modem is ready

to place and receive calls.

If you have a standard analog telephone attached to the

digital modem’s analog voice port, you can place a voice

call in the normal fashion. You should have the ability to

obtain a dial tone, enter digits, and connect to your

destination. While the voice call is being placed, either

the B-1 or B-2 channel LEDs will flash yellow. Once the

voice call is connected and the other party picks up the

phone, the B-1 or B-2 LEDs that were flashing will now

remain lit until the call is disconnected.

If you do not hear a dial tone or cannot establish a call,

there is most likely a problem with the configuration of

your ISDN line. Call the telephone company and have it

verify that your line is configured for circuit-switched

voice and data service.

6Monitor the B-1 and B-2 LEDs.

Data calls typically involve more interactions than voice calls do.

Your computer, applications software, or the remote destination

can prevent establishment of a data call. If you have been able

to perform all of the above steps, your 3Com Impact digital

modem is most likely functioning correctly.

3-4 CHAPTER 3: TROUBLESHOOTING

■If you are unable to establish a data call, carefully monitor the

B-1 and B-2 LEDs while attempting a data call. The B-1 and

B-2 LEDs flash green during the data call establishment

phase. They then remain continuously green once the data

connection is established.

■If neither of the B-1 or B-2 LEDs flashes green, check to make

sure that your computer is turned on and operational, that

your 3Com Impact digital modem cable is properly

connected and not damaged, and that your application

software has sent an AT dial command in the proper format.

Depending upon the location of the destination call you are

dialing, there may be an incompatible local or toll telephone

company. Though this is less likely, if you suspect a telephone

company problem in dialing local or toll data connections,

contact your local telephone company and have it verify that

you can dial a data call to the destination telephone number.

7If you are able to establish a data call, in which the B-1 or

B-2 green LED remains lit and you receive a CONNECT

message at your application software, but you are unable

to send data, then it is possible that:

■There is a difference in the local and remote B channel

data rates.

■There is a mismatch in the data communications

protocols.

■There is an interoperability mismatch between the local

and remote applications.

■Make sure that the local and remote data applications have

communication capability and are properly configured.

Once you have verified that communication capability

exists, make sure that the B channel call data rate is the

same as the remote destination call data rate. The default B

channel data rate used by the digital modem is 56 Kbps.

Under some circumstances, the data rate may be

increased to 64 Kbps at both ends of the connection.

Downloading Firmware to Your External Digital Modem 3-5

8If problems persist, refer to Appendix C, “Technical Support.”

If you have gone through the troubleshooting tips and still

have not been able to resolve the problem, contact

technical support. Please have the serial number of your

3Com Impact digital modem; a list of symptoms, including

any LED status information; computer display status; and

relevant information about your application software ready

when you call.

Downloading Firmware to Your External Digital

Modem

Data communications is an evolving technology. To keep

pace with this evolution, your digital modem has been

uniquely designed to be user-upgradable. As recommended

by 3Com technical support, you may need to download the

latest firmware to your digital modem. You can use the

following procedure to download the updated firmware to

your digital modem.

For IBM and IBM-Compatible PCs

This section provides instructions on downloading firmware

from your PC to your digital modem.

1Obtain the latest firmware file from the 3Com FTP site

ftp.3Com.com.

2Copy the firmware file to your computer.

3Double-click the 3Com Impact icon to access the

Configuration dialog box, shown in Figure 2-3.

4Click the Tools button.

The Firmware and Tests buttons appear.

Use the Tests tool only under the direction of service

personnel.

5Click the Firmware button.

The Firmware dialog box appears.

3-6 CHAPTER 3: TROUBLESHOOTING

6Select the firmware file that you copied from 3Com’s

FTP site and click OK to start the download to the

3Com Impact digital modem.

The download will take several minutes.

7Click the Exit button to exit the utility.

For Macintosh Computers

This section provides instructions on downloading firmware

from your Macintosh to your digital modem.

1Obtain the latest firmware file from the 3Com FTP site

ftp.3Com.com.

2Copy the firmware file to your computer.

3Double-click the 3Com Impact icon to access the

Utility dialog box.

Use the Diagnostics button only under the direction of service

personnel.

4Click the Update Firmware button.

5Select the firmware file that you copied from 3Com’s

FTP site and click OK to start the download to the

3Com Impact digital modem.

A message box appears and allows you to confirm the

download. The download will take several minutes.

6Click OK.

AAT COMMAND SET

OVERVIEW

Most communications software supports an AT command

line initialization string. The initialization string sets up the

3Com Impact digital modem to negotiate and connect

with a remote modem. Before dialing, the software sends

the initialization string to the 3Com Impact digital modem.

The communications software or server stores the

initialization string and uses it each time it dials. In most

situations, an initialization string is not necessary with the

3Com Impact digital modem. If an initialization string is

required by the communications software or server, use the

Hayes default initialization string.

Software that communicates using AT commands

(ATtention codes) is required to control the 3Com Impact

digital modem. You can enter these codes manually.

However, they are often entered automatically by modem

communications software. For a summary of the AT

command set, see Appendix B, “AT Commands, Registers, and

Result Codes.” Below is a sample AT command line:

AT V1 D 1 800 555 3333 [Enter]

AT gets the attention of your 3Com Impact digital modem.

V1 sets the digital modem to verbose mode so that it sends

its responses in English words instead of numbers.

D tells the digital modem to dial an ISDN digital connection

to the phone number that follows.

[Enter] sends the command line to your 3Com Impact digital

modem.

A-2 APPENDIX A: AT COMMAND SET OVERVIEW

Follow these steps to use AT commands:

1Launch your communications software.

Be sure your communications software is in terminal mode.

2Be sure the digital modem is in command mode

(sometimes called local mode or terminal mode) so that it

interprets your commands.

When your computer is powered on, the digital modem

automatically starts in command mode. If you have recently

used the digital modem to make a call and have not yet

disconnected, type +++ to switch to command mode.

3Type:

AT <commands> [Enter]

An AT command line starts with the characters AT. The

command line can accept up to 40 command characters in

the line (not including the two AT characters, spaces, or

[Enter]).

After completing its tasks, the 3Com Impact digital modem

sends a message to the screen.

BAT COMMANDS,

REGISTERS, AND RESULT

CODES

The 3Com Impact ISDN digital modem commands are

summarized in Table B-1, modem commands for the internal

analog modem in Table B-1, remote S registers in Table B-3,

and digital modem result codes in Table B-4.

AT Command Set for the 3Com Impact

Digital Modem

Table B-1 summarizes the AT command set.

Table B-1 AT Command Set Summary

Command Function (Example) Description

AAnswer incoming circuit-switched

digital modem call (AT A)

Answers an incoming call.

&C Serial port CD control (AT &C2) &C0 forces CD to remain on at all times.

&C1 forces CD to follow the state of

carrier from the remote system. CD turns

on after CONNECT message is sent to

host (default).

&C2 forces CD to remain on except

temporarily after disconnect.

D (ATD5551234) Dials an outgoing 56/64 Kbps

circuit-switched digital connection.

DT (ATDT5551234) Dials an outgoing analog modem call,

using the optional V.32bis modem, at a

maximum modem line speed of

14.4 Kbps using touch-tone dialing.

DP (ATDP5551234) Dials an outgoing analog modem call,

using the optional V.32bis modem, at a

maximum modem line speed of

14.4 Kbps using pulse dialing.

(continued)

B-2 APPENDIX B: AT COMMANDS, REGISTERS, AND RESULT CODES

&D DTR control (AT &D0) &D0 causes digital modem to ignore DTR

from host.

&D1 causes digital modem to enter

command state on detecting on-off

transition of DTR.

&D2 causes digital modem to hang up

current calls upon on-off transition of DTR

and prepares serial port to accept AT

command at any speed (default).

E AT command echo (AT E0) E0 disables the echo of AT commands

back to the host computer.

E1 enables the echo of AT commands to

the host computer (default).

&F Restore factory defaults (AT &F) Restores all factory default settings.

H Hang up (AT H) Hangs up the current connections.

I Identification (AT I0) I0 displays the product and options ID.

I1 displays the flash memory checksum.

I4 displays the modem product code,

precomputed checksum, firmware

revision number, model, interface type,

country code, and data pump model.

O Enter connect state (AT O) Causes the digital modem to go out of

command mode into on-line mode.

Q Result code control (AT Q0) Q0 enables the output of result codes

(default).

Q1 disables the output of result codes.

Q2 disables the output of result codes in

answer mode only.

\Q Serial port flow control (AT \Q1) \Q0 disables flow control.

\Q1 enables bidirectional XON/XOFF

software flow control.

\Q3 enables bidirectional RTS/CTS

hardware flow control (default).

%R Read all S registers (AT %R) Provides an output list of all S registers.

SN? Read configuration register

(AT S60?)

Reads a specific S register setting.

SN= Write configuration register

(AT S60=64)

Writes to a specific S register.

(continued)

Table B-1 AT Command Set Summary (continued)

Command Function (Example) Description

AT Command Set for the 3Com Impact Digital Modem B-3

\S Read on-line status: command

settings (AT \S)

Reads the status of any parameters that

have been modified through AT

commands.

\T Link inactivity timer (AT \T1) \T0 disables inactivity timer (default).

\Tn link inactivity timer in minutes. The

digital modem automatically disconnects

the call if no activity is sensed within n

(n = 0–255) minutes.

V Result code format (AT V0) V0 enables short form result codes.

V1 enables long form result codes

(default).

&W Stores configuration (AT &W) Stores the configuration of all S registers

that are not part of the digital modem

initial configuration set.

Z Reset (AT Z) Disconnects all calls in progress and

performs a complete digital modem

system reset.

+++ Enter command state Causes digital modem to enter the

command state if it is currently in the

on-line state.

$B Set baud rate (AT $B57600) 0 — Autobaud (default). Other settings

are 1200, 2400, 4800, 9600, 19200,

38400, 57600, and 115200.

%V Show version number (AT %V) Displays digital modem firmware version.

Table B-1 AT Command Set Summary (continued)

Command Function (Example) Description

B-4 APPENDIX B: AT COMMANDS, REGISTERS, AND RESULT CODES

AT Command Set for Internal Analog Fax Modem

Table B-1 summarizes the AT command set for the internal

analog modem.

Table B-2 AT Command Set Summary for the Internal Analog Modem

Command Function (Example) Description

BSet 1200 bps (operation= 0) Initiates calls using either ITU-T V.220 or

Bell 212a at 1200 bps.

0 — V.22

1 — Bell 212a (default)

C1 ATC1 Modem responds with OK

F Select modem modulation mode 0 — Auto detect (default)

1 — V.21/Bell 103

3 — V.23

4 — V.22/Bell 212a

5 — V.22bis

6 — V.32bis/V.32 4800 bps

7 — V.32bis/V.32 7200 bps

8 — V.32bis/V.32 9600 bps

9 — V.32bis 12000 bps

10 — V.32bis 14400 bps

L Modem speaker volume control 0,1 — Low

2 — Medium (default)

3 — High

M Modem speaker operation 0 — Off

1 — On during handshaking, off while

receiving carrier (default)

2 — On during handshaking, on while

receiving carrier

3 — Off while receiving carrier, on

during answering

(continued)

AT Command Set for Internal Analog Fax Modem B-5

XSelect the subset of result

messages that will be used by

the modem to inform the PC of

the results of commands

0 — Basic call progress

1 — Basic call progress and connection

rate

2 — Basic call progress and connection

rate

3 — Basic call progress and connection

rate

4 — All call progress and connection rate

%E Line quality monitor control 0 — Disable

1 — Enable and retrain

2 — Enable and fallback/forward

3 — Enable and auto-retrain but hang up

immediately if line quality becomes

insufficient

%L Return received line signal level Returns a value that indicates the

received line signal level

%Q Report line signal quality Reports the line signal quality

&G Generate guard tone 0 — Disable (default)

1 — Select 1800 Hz guard tone

&V Display current configuration

\A Set MNP max block size 0 — 64

1 — 128

2 — 192

3 — 256

\B Transmit break to remote Sends break to remote modem with a

length in multiples of 100 ms (n x 100 ms)

in non-error corrected mode only.

n = 1–9

\G End-to-end, modem-to-modem

flow control

0 — Disable (default)

1 — Enable

\L MNP mode 0 — Stream (default)

1 — Block

(continued)

Table B-2 AT Command Set Summary for the Internal Analog Modem (continued)

Command Function (Example) Description

B-6 APPENDIX B: AT COMMANDS, REGISTERS, AND RESULT CODES

\N Set preferred error-correcting

mode to be negotiated in a

subsequent data connection

0 — Normal speed buffered

1 — Direct

2 — Reliable link

3 — Auto reliable

4 — Force LAPM

5 — Force MNP

-K MNP extended services Enables/disables conversion of a V.42

LAPM connection to an MNP 10

connection.

0 — Disable

1 — Enable

2 — Enable; inhibits MNP extended

services initiation during V.42 LAPM

answer mode detection phase

-Q MNP 10 fallback to 2400 bps

(V.22bis)/1200 (V.22)

Enables or disables fallback from MNP 10

to V.22bis/V.22.

0 — Disable

1 — Enable (default)

*H Link negotiation speed Controls the connection speed for link

negotiations before upshift occurs

between two MNP Class 10 modems.

0 — Highest rate (default)

1 — 1200 bps

2 — 4800 bps

+F All fax commands (AT+fax sub-

command)

All fax commands

Table B-2 AT Command Set Summary for the Internal Analog Modem (continued)

Command Function (Example) Description

Remote S Registers B-7

Remote S Registers

The 3Com Impact digital modem supports the S registers

listed in Table B-3. All S registers except S0 are the 3Com

extended registers.

Table B-3 Remote S Registers

Registers Descriptions

S0 Auto Answer

0 — Disabled (default)

1 — Enabled

S50 ISDN Switch Signaling Type:

1 — AT&T 5ESS Custom

3 — NI-1/AT&T 5ESS (default)

6 — NI-1/NTI DMS 100 or Siemens EWSD

S51 Phone #1

S52 Phone #1 Service Profile ID (SPID)

S53 Phone #2 (if required by your carrier)

S54 Phone #2 Service Profile ID (SPID) (if required by your carrier)

S55 Terminal Endpoint Identifier 1:

Stores the first TEI assigned by the switch if a second

directory number is required by your carrier. A value of 255

indicates no TEI has been assigned. This field is read-only.

S56 Terminal Endpoint Identifier 2:

Stores the second TEI assigned by the switch. A value of 255

indicates no TEI has been assigned. This field is read-only.

S57 Terminal Initialization State:

Indicates the status of the first TEI using SPID 1. This field is

read-only.

0 — 3Com Impact digital modem has not attempted

initialization

1 — 3Com Impact digital modem has initialized successfully

using SPID 1

2 — 3Com Impact digital modem has failed initialization

using SPID 1

(continued)

B-8 APPENDIX B: AT COMMANDS, REGISTERS, AND RESULT CODES

S58 Terminal Initialization State:

Indicates the status of the second TEI using SPID 2. This

information is provided only if your carrier requires a second

directory number. This field is read-only.

0 — 3Com Impact digital modem has not attempted

initialization

1 — 3Com Impact digital modem has initialized successfully

using SPID 2

2 — 3Com Impact digital modem has failed initialization

using SPID 2

S59 U Interface Status:

This field is read-only.

0 — U interface is not synchronized with the switch

1 — U interface is synchronized and ready

S60 B Channel Data Rate:

56 — 56 Kbps (default)

64 — 64 Kbps

S61 Outgoing Call Type:

0 — Follow dial modifiers (default)

2 — ISDN

3 — Internal analog fax modem

S63 (only for models with

an internal fax modem)

Incoming Voice Call Routing (bit map)

Bit Position/Feature:

0 — Phone #1 internal analog fax modem

1 — Phone #1 Phone Out port

2 — Phone #2 internal analog fax modem

3 — Phone #2 Phone Out port

S65 Voice Automatic Number Identification:

Displays the phone number of an incoming voice call. This

field is read-only.

S66 Data Automatic Number Identification:

Displays the phone number of an incoming data call. This

field is read-only.

(continued)

Table B-3 Remote S Registers (continued)

Registers Descriptions

Remote S Registers B-9

S70 Dynamic Bandwidth Allocation:

0 — DBA disabled

1 — DBA enabled (default)

S71 B Channel Protocol:

0 — QuickSelect (default)

1 — Async-Sync PPP conversion

2 — V.120

S73 V.120 Frame Type:

0 — I frame (default)

1 — UI frame

S74 V.120 Maximum Frame Size (range 240–256):

256 — Maximum frame size of 256 is used (default)

248 — Maximum frame size of 248 is used (for AdTranâ

compatibility, use 253)

S80 Multilink PPP:

0 — Disable

1 — Enable (default)

S81 Multilink PPP Directory Number:

If the destination to which you are dialing a Multilink PPP

call requires two separate directory numbers, you must

include the second telephone number of up to 15 digits in

this S register. If left blank, then the number used to dial the

first link is used.

S82 Multilink PPP Endpoint Identifier Class:

If required, this information is provided by your Internet

service provider.

1 — Locally Assigned Address

2 — Internet Protocol (IP) Address

3 — IEEE 802.1 Globally Assigned MAC Address

4 — PPP Magic-Number Block

5 — Public Switched Network Directory Number

S83 Multilink PPP Endpoint Identifier (up to 20 characters)

If required, this information is provided by your Internet

service provider.

Table B-3 Remote S Registers (continued)

Registers Descriptions

B-10 APPENDIX B: AT COMMANDS, REGISTERS, AND RESULT CODES

Digital Modem Result Codes

Table B-4 lists the 3Com Impact digital modem result codes.

Table B-4 3Com Impact Digital Modem Result Codes

Short Form Long Form Meaning

0 OK Indicates that the most recent command or

action was successfully completed.

2 RING Indicates that an incoming call is present

and no AT Answer command is

outstanding.

3 NO CARRIER Indicates that the most recent call attempts

did not establish a call or that the physical

ISDN interface is not operational.

4 ERROR Indicates that the most recent command or

action was not successfully completed.

7 BUSY Indicates that the most recent call attempt

did not connect because the remote

destination was busy.

5 CONNECT 1200 Indicates 1200 bps analog modem

connection.

10 CONNECT 2400 Indicates 2400 bps analog modem

connection.

11 CONNECT 4800 Indicates 4800 bps analog modem

connection.

12 CONNECT 9600 Indicates 9600 bps analog modem

connection.

15 CONNECT 14400 Indicates 14400 bps analog modem

connection.

28 CONNECT 28800 Indicates 28800 bps analog modem

connection.

56 CONNECT 56000 Indicates 56000 bps digital modem

connection.

64 CONNECT 64000 Indicates 64000 bps digital modem

connection.

CTECHNICAL SUPPORT

3Com provides easy access to technical support information

through the variety of services described in this appendix.

On-line Technical Services

3Com offers worldwide support, through the following:

■3Com Bulletin Board Service (3ComBBS)

■World Wide Web Site

■Ask3ComSM on CompuServeâ

■3ComFactsSM Automated Fax Service

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 seven days a week, 24 hours a day. To reach the

service, set your modem to 8 data, no parity, and 1 stop bit.

Country Baud Rate Telephone Number

Australia up to 14400 baud (61) (2) 955 2073

France up to 14400 baud (33) (1) 69 86 69 54

Germany up to 9600 baud

up to 9600 baud

(49) (89) 627 32 188

(49) (89) 627 32 189

Hong Kong up to 14400 baud (852) 537 5601

Italy (fee required) up to 9600 baud (39) (2) 273 00680

Japan up to 14400 baud (81) (3) 3345 7266

Singapore up to 14400 baud (65) 534 5693

Taiwan up to 14400 baud (886) (2) 377 5838

(886) (2) 377 5840

U.K. up to 14400 baud (44) (144) 227 8278

U.S. up to 14400 baud

ISDN V.120

(1) (408) 980 8204

(1) (408) 654-2703

C-2 APPENDIX C: TECHNICAL SUPPORT

World Wide Web Site

Access the latest networking information on 3Com’s World

Wide Web site by entering our URL into your Internet

browser:

http://www.3Com.com/

This service features news and information about 3Com

products, customer service and support, 3Com’s latest news

releases, selected articles from 3TECHâ, 3Com’s

award-winning technical journal, and more.

Ask3Com on CompuServe

Ask3Com is a CompuServe-based service containing patches,

software, drivers, and technical articles about all 3Com

products, as well as an interactive forum for technical

questions. To use Ask3Com, you need a CompuServe account.

To use Ask3Com:

1Log on to CompuServe.

2Enter go threecom

3Press [Return] to see the Ask3Com main menu.

3ComFacts Automated Fax Service

3Com Corporation’s interactive fax service, 3ComFacts,

provides data sheets, technical articles, diagrams, and

troubleshooting instructions on 3Com products 24 hours a

day, seven days a week. Within this service, you may choose

to access CardFactsâ for adapter information, or NetFactsâ

for network system product information.

■CardFacts provides adapter installation diagrams,

configuration drawings, troubleshooting instruction, and

technical articles.

Document 9999 provides you with an index of adapter

documents.

Support from Your Network Supplier C-3

■NetFacts provides data sheets and technical articles on

3Com Corporation’s hub, bridge, router, terminal server, and

software products.

Document 8888 provides you with an index of system

product documents.

Call 3ComFacts using your touch-tone telephone.

International access numbers are:

Local access numbers are available within the following

countries:

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.

Country Fax Number

Hong Kong (852) 537 5610

U.K. (44) (144) 227 8279

U.S. (1) (408) 727 7021

Country Fax Number Country Fax Number

Australia 800 123853 Italy 1678 99085

Denmark 800 17319 Netherlands 06 0228049

Finland 98 001 4444 Norway 800 11062

France 05 90 81 58 Sweden 020 792954

Germany 0130 8180 63 U.K. 0800 626403

C-4 APPENDIX C: 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.

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 (800) 876 3266 (408) 764 7120

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 One year

Spare parts and spares kits 90 days

If a product does not operate as warranted 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 pursuant to

any warranty.

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 magnetic

media containing software against failure during the warranty period. No updates are provided.

3Com's sole obligation hereunder 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 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 by 3Com.

WARRANTIES EXCLUSIVE: IF A 3COM PRODUCT DOES NOT OPERATE AS WARRANTED ABOVE,

CUSTOMER’S SOLE REMEDY SHALL BE REPAIR, REPLACEMENT, OR REFUND OF THE PURCHASE

PRICE PAID, AT 3COM’S OPTION. THE FOREGOING WARRANTIES AND REMEDIES ARE EXCLUSIVE

AND ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, EITHER IN FACT OR BY

OPERATION OF LAW, STATUTORY OR OTHERWISE, INCLUDING WARRANTIES OF

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 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 ANY OTHER CAUSE BEYOND THE RANGE OF THE

INTENDED USE, OR BY ACCIDENT, FIRE, LIGHTNING, OR OTHER HAZARD.

LIMITATION OF LIABILITY: IN NO EVENT, WHETHER BASED IN CONTRACT OR TORT (INCLUDING

NEGLIGENCE) SHALL 3COM BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL, OR

PUNITIVE DAMAGES OF ANY KIND, OR FOR LOSS OF REVENUE, LOSS OF BUSINESS, 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.

Some states do not allow the exclusion of implied warranties or the limitation of incidental or

consequential damages for consumer products, so the above limitations and exclusions may not

apply to you. This warranty gives you specific legal rights which may vary from state to state.

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

FCC CLASS B CERTIFICATION STATEMENT

3Com Corporation

Model Nos: 3C871, 3C872, 3C876, 3C877

FCC ID: LP2QAREMOTE

Made in U.S.A.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following two

conditions:

1 this device may not cause harmful interference, and

2 this device must accept any interference received, including interference that may cause

undesired operation.

WARNING: This equipment has been tested and found to comply with the limits for a Class B

digital device, pursuant to Part 15 of the FCC Rules, and the Canadian Department of

Communications Equipment Standards entitled, “Digital Apparatus,” ICES-003. These limits are

designed to provide reasonable protection against harmful interference in a residential

installation. This equipment generates, uses and can radiate radio frequency energy and, if not

installed and used in accordance with the instructions, may cause harmful interference to radio

communications. However, there is no guarantee that interference will not occur in a particular

installation. If this equipment does cause harmful 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 or relocate the receiving antenna.

■Increase the separation between the equipment and receiver.

■Connect the equipment into an outlet on a circuit different from the one which the receiver is

connected to.

■Consult the dealer or an experienced radio/TV technician for help.

The user may find the following booklet prepared by the Federal Communications Commission

helpful:

The Interference Handbook

This booklet is available from the U.S. Government Printing Office, Washington, D.C. 20402. Stock

No. 004-000-00345-4.

NOTE: In order to maintain compliance with the limits of a Class B digital device, 3Com requires

that you use quality interface cables when connecting to this device. Changes or modifications

not expressly approved by 3Com could void the user’s authority to operate this equipment. Refer

to the manual for specifications on cabling types.

CANADIAN NOTICE

The Industry Canada label identifies certified equipment. This certification means that the

equipment meets certain telecommunications network protective, operation, and safety

requirements. The Department does not guarantee the equipment will operate to the users’

satisfaction.

Before installing this equipment, users should ensure that is permissible to be connected to the

facilities of the local telecommunications company. The equipment must also be installed using

an acceptable method of connection. In some cases, the inside wiring associated with a

single-line individual service may be extended by means of a certified connector assembly. The

customer should be aware that compliance with the above conditions may not prevent

degradation of service in some situations.

Repairs to certified equipment should be made by an authorized Canadian maintenance facility

designated by the supplier. Any repairs or alterations made by the user to this equipment, or

equipment malfunctions, may give the telecommunications company cause to request the user

to disconnect the equipment.

Users should ensure for their own protection that the electrical ground connections of the power

utility, telephone lines, and internal metallic water pipe system, if present, are connected

together. This precaution may be particularly important in rural areas.

CAUTION: Users should not attempt to make electrical ground connections by

themselves, but should contact the appropriate inspection authority or an electrician,

as appropriate.