The telephone number extension field is not included when an invitation message is sent to a PBX or to a PSTN from the Mediation Server application in Communications Server 2007

A computer that is running the Mediation Server application in Microsoft Office Communications Server 2007 sends an invitation message to a private branch exchange (PBX) or to a Public Switched Telephone Network (PSTN) gateway. However, the telephone number extension field is not included. This problem occurs even if the Office Communications Server (OCS) network provides the extension field to Mediation Server.

This problem is fixed in the update package for Communications Server 2007 Mediation Server 2007 that is dated December 17, 2007.

For more information about the update, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

An example of the problem that is described in the "Symptoms" section occurs when the FROM field of the invitation message does not contain the following telephone uniform resource identifier (URI): Note The URI is described in the "19.1.6: Relating SIP URIs and tel URLs" section of Request for Comments (RFC) 3261, "SIP: Session Initiation Protocol."