Dial-Up Networking Error: There Is No Dial Tone

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SYMPTOMS

When you dial one of your Dial-Up Networking phonebook entries, you may receive the following error:

   There is no dial tone.

CAUSE

The dial string is greater than 40 characters; this causes it to be divided into two dial strings, which some modems do not interpret correctly.

RESOLUTION

To resolve this problem, do either of the following:

• Reduce the length of the dial string.

  -or-

• Use a different modem type.

MORE INFORMATION

A predefined and hard-coded total limit of 34 dialing digits per dialing string is imposed within Dial-Up Networking on Windows NT. The 34-digit limit does not include the dialing prefix ATDT, nor suffixes (;), nor NULL characters.

When Dial-Up Networking encounters a dialing string with more than 34 dialing digits, it divides the string and sends the remaining digits in a second dialing string. Some modem brands only allow a single dialing string to be sent with each ATDT command, and any additional strings sent with a second ATDT command return the error above.