Polycom 400 - Manual (Page 122)

Polycom Telephone User Guide Set Up Outlook for TAPI 115
621-00000092
4. Click Call Contact on the menu (circled in the previous screen)
to open the New Call dialog box.
5. Click Dialing Options to open the Dialing Options dialog box.
6. Click on the drop-down menu in the Connect using line field
and scroll down any entries until you find your telephone
number (circled).