It doesn't work this way with Cisco products. The router must use a TCL script that answers the call and listens for the specific tones while playing ringback to see if this is a voice or fax call. This adds a delay to all calls because this ringback is fake; the user's phone does not actually ring until the TCL script timeout occurs defaulting to a voice call. Based on what the TCL script decides it chooses different called number and dial-peers.
I have done this in real life and let me tell you, it isn't worth it. It's more trouble than it is worth and your time would be better spent buying the extra DIDs to give people a dedicated fax number.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...