If the service provider supplies a caller ID, IP Office can pass it to the answering phone or application and is includes it in any call log or history supported by the phone or application. If the caller ID matches a number in the directory, IP Office displays the matching directory name.

If IP Office Phone Manager or TAPI service links to a database, IP Office performs an automatic query on the supplied Caller ID and displays the caller's record to the user before the call is answered.

For outgoing calls, IP Office can insert a system wide caller ID or set a flag to have caller ID withheld. For users with a direct dial number routed to their extension, IP Office uses that number as their caller ID for outgoing calls. Alternatively, IP Office can use short codes to specify the caller ID that should be sent with outgoing calls.