Because the Exchange 2010 Unified Messaging server is essentially a voicemail system, all the other components must be in place and operational before introducing it. This includes the following:
• PBX—The existing PBX must be configured with the appropriate hunt groups to route calls correctly.
• Hunt groups—The hunt groups and pilot numbers should be provisioned in the PBX. The auto attendant pilot numbers and the subscriber access pilot numbers should be part of a rollover group so that if one number is busy, the call will roll over to the next line.
Set up separate hunt groups and pilot access numbers on the PBX for the auto attendant and the subscriber access lines.
• IP/VoIP gateway—The IP gateway must be ...