Direct Inward Dial (DID) Numbers
This distributed direct number can be used by your system’s call routing software to route the call to an individual phone, or groups of phones. This service is typically used to reduce the workload on a reception position by giving members of staff or departments individual numbers so they can be called directly. For convenience it is common to have the extension or group number the same as the digits supplied from the network. In North America, T1 circuits are required for DID.