Give Me Your Commands
I own a relatively inexpensive modem, and less than top-of-the-line software for my PC. I would like to write programs in BASIC to enhance my modem's capabilities. I would like to find a list of the Hayes command set for my programs.
Peter Laird
The manual that came with your modem should include a complete list of the commands it understands. Most modems these days claim to be "Hayes compatible," but some modems are decidedly more compatible than others. Many of the so-called Hayes compatible modems understand only a limited subset of the full command set of genuine Hayes modems, while others include new commands above and beyond those in the standard Hayes set. If your modem isn't truly Hayes compatible, then using these commands won't have any effect.
Here is a list of the most common Hayes commands:
| AT | A | Answer immediately without waiting for a ring |
| AT | Dn | Dial a number, where n is the number to dial |
| AT | Fn | Select duplex mode (n is 1 for local echo, 0 for no echo) |
| AT | Hn | Select hook status (n is 1 for off hook, 0 to hang up) |
| AT | O | Switch from command state to online state |
| AT | P | Use pulse dialing |
| AT | T | Use tone dialing |
| AT | Z | Reset modem to its default configuration |
| A/ | Repeat last command (useful for redialing) |
All but the last of these commands are preceded by AT. The AT prefix tells the modem to pay ATtention to the following characters. (Hayes modems require that the AT characters be in uppercase; some compatibles may allow either uppercase: or lowercase.) To use any of these commands, send them to your modem as you would any other piece of information. The modem must be in its command state to understand the commands; again, see your modem manual for more information.