As was mentioned in an earlier post the University is moving away from the Bell Canada Centrex system to a BroadConnect Telecom VoIP system. Many departments have already moved over and our department will be piloting this system very soon in preparation to moving everyone over in the new year.
One consequence of the presence of two different systems on campus is that those of us still on the Centrex system have to use 9 plus the full 10 digit telephone number to call anyone who has already moved to the VoIP system (for example, people in Engineering or Computer Science). The usual 5-digit dialing still works between two Centrex users (or between two VoIP system users).
The main University website for this changeover is VoIP at U of T.