You try to use Microsoft Office Communicator 2007 R2 to make an audio call or a video call to another Office Communicator 2007 R2 user. However, you cannot determine whether this user supports an audio call or a video call before you start the call.
To fix this problem, install the following cumulative update:
2291453 Description of the cumulative update package for Communicator 2007 R2: November 2010
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
After you apply this update to the Office Communicator 2007 R2 client, the following contact presence states will display additional text information to describe the availability of audio communications for the Office Communicator 2007 R2 contacts that are not locally configured for VoIP communications.