When you need to dial a phone number using a TAPI-compliant program, you must provide the phone number to TAPI in a way that it can interpret and correctly dial the number from your current location. For information about how TAPI phone numbers are formatted, and to configure how Windows dials those numbers, see "Changing How Windows Dials Phone Numbers" in the Network and Sharing Center Operations Guide (http://go.microsoft.com/fwlink/?linkid=81008).

Additional references