ARCHIVED: How does call waiting affect a modem connection, and how can I deactivate it?

If you have call waiting on your telephone line, an incoming call can interrupt your modem session and cause you to lose your connection. Most telephone companies allow you to disable call waiting temporarily. With call waiting disabled, incoming callers will hear ringing, or will be connected to your voice mail if you have that service, but your modem connection will not be affected.

The code for disabling call waiting varies between telephone companies, and some companies charge for this additional service.

If you live in Indiana and have local phone service through AT&T, the code to disable call waiting is *70 (if you have rotary service, 1170). If your service is through Smithville Telephone Company, the code is 70#. To disable call waiting from campus telephones in Bloomington, the code is *96. To disable call waiting from campus telephones in Indianapolis, the code is *99. If your service is through another telephone company, consult your telephone book or call the operator for the code to disable call waiting.

The disable call waiting code (for example, *70, 1170, *96) must be part of the dialing command or precede the telephone number in your modem's dial-up information. You can add this command before the phone number separated by two commas, as in the following examples:

  *70,,8565200

  *96,,65200

The double commas provide a short pause before the telephone number is dialed.

Alternatively, you can add the disable call waiting code to your modem initialization string, as in the following examples:

  ATDT*70

  ATDT*96

As soon as you hang up, call waiting is turned back on.