3Com Megahertz

Contents | Index | Support | Knowledge Base | Software

Modem User Guide

Modem Features 





Modem Features

AT Command Help Screens

AT commands allow you to control many of the functions of your modem. You can use AT commands by typing them at the command line of any Terminal program.

Your modem can display screens summarizing AT commands (AT$ and AT&$), dial command options (ATD$), and S-register functions (ATS$) (see AT Commands).

Automatic Calling Card Dialing

Whenever you make a calling card call, your modem will detect the tone that sounds prior to entering your calling card number. You can have the modem automatically enter your calling card number and place the call by entering the following string:

    ATDT <phone#>&<calling card#>

Call Progress Detection

An optional set of result codes lets you know when:

These result codes, and the commands that enable or disable these result codes, are controlled by the ATXn command. See the listing for ATXn in AT Commands and Result Codes .

Dialing Stored Phone Numbers

Your modem can store up to four of your most frequently called numbers. See AT&Z in AT Commands for storing numbers. For dialing stored numbers, see ATDS.

For example, suppose you are dialing a phone number of 123-4567, and it is the first number you have stored. You would enter AT&Z0=1234567 to store the number, and ATDS0 to dial it. To dial the second phone number in the stored numbers list, you would enter AT&Z1=9876543 to store it, and ATDS1 to dial it.

Digital Line Guard

For landline connections, protects the card circuitry from overvoltage from ISDN or digital PBX lines.

Exclusive Line Probing

Exclusive Line Probing technology for V.90 connections automatically steers you around even the worst line impairments, allowing faster connections and transfers.

Software Upgrade

Your PC Card can be updated to correct problems without having to returning your card to 3Com. Current software upgrades and the instructions to use them are on the BBS, the 3Com Web site (www.3com.com), and online services (see Technical Support).

If your modem is functioning properly, there is usually no need to upgrade it. In any case, we recommend upgrading only under the direction of a Customer Support Application Engineer.

Redialing the Last Dialed Number

Your modem stores each dialed number until another number is dialed. Enter ATDL to redial the last number dialed during the current session.


With V.90, your modem will be able to download (receive) data files at up to 56,000 bps. Uploads travel at V.34+ speeds. A V.90-compatible local analog phone line and V.90-capable service provider are required for these high-speed downloads and uploads.



NOTE: Capable of receiving at up to 56 Kbps and sending at up to 31.2 Kbps. Actual download speeds you experience may be lower due to varying line conditions. Requires compatible phone line and server equipment. Complies with both the V.90 56K standard and x2 technology protocol.