To place calls to a telephone

From NetMeeting 3.0 Help

To place calls to a telephone

On the Tools menu, click Options.
On the General tab, click Advanced Calling.
In the Advanced Calling Options dialog box, under Gateway settings, select the Use a gateway to call telephones and videoconferencing systems check box.
In Gateway, type the computer name.

Note

Certain gatekeeper computers can also allow you to use NetMeeting to call a telephone. For more information, contact your system administrator.