3Com 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.

Contents

Main 3Com Corporation 95052-8145 Santa Clara, California 5400 Bayfront Plaza C ONTENTS 3 A C B F IGURES T ABLES A How to Use This Guide Introduction UIDE Conventions Table 1 and Table 2 list text and icon conventions that are used throughout this guide: I NTRODUCTION Page 3Com Impact Digital Modem Features Data Capabilities Voice Capabilities Simultaneous Data and Voice Capabilities Analog Modem Capabilities 3Com Impact Digital Modem Package Contents Standard Package Contents Additional Contents ISDN Digital Line Conguration Requirements Computer System Requirements IBM PC or Compatible Requirements Apple Macintosh Requirements Cabling Requirements 2 C THE DIGITAL MODEM Page Installing the 3Com Impact Digital Modem Installing the Digital Modem in an IBM-compatible PC Page Page Conguring the 3Com Impact Digital Modem Conguration for IBM PC or Compatible Computer Page Page Page Page Page Conguration for Apple Macintosh Computer Page Placing and Receiving Calls Placing ISDN Data Calls Multilink PPP Calls With Dynamic Bandwidth Allocation Page Placing Analog Modem Calls Using Communications Software to Place Calls Receiving Data Calls Using the Phone Out Port Placing Calls Using the Phone Out Port Receiving Calls Using the Phone Out Port Protocol Support Async-Sync PPP Conversion QuickSelect 3 Troubleshooting Tips Page Page Page Downloading Firmware to Your External Digital Modem Page A O Page B REGISTERS, AND RESULT C AT Command Set for the 3Com Impact Digital Modem Table B-1 summarizes the AT command set. Page Page AT Command Set for Internal Analog Fax Modem Table B-1 summarizes the AT command set for the internal analog modem. Page Page Remote S Registers Page Page Digital Modem Result Codes Table B-4 lists the 3Com Impact digital modem result codes. C On-line Technical Services 3Com Bulletin Board Service World Wide Web Site Ask3Com on CompuServe 3ComFacts Automated Fax Service Support from Your Network Supplier Support from 3Com Returning Products for Repair