How do you pass the external caller ID from the PSTN to OCS? I have followed your instructions exactly and the caller ID that shows up on the communicator is an internal extension. I have a CCM 4.2 and I am running an OCS 2007 R2 Enterprise. When a call comes in we have a call processor in CallXpress that gives options to transfer the call. I enter in an OCS extension that should transfer me to a communicator and it does, but I see a CX extension instead of the external caller-ID. If I call a standard phone the same way, I can see the external ID, so it seems like it has to be something on the CM side. Any ideas?