DID

Direct Inward Dialing (DID) is a telephony feature that assigns individual phone numbers to users or extensions within a PBX system, without requiring a separate physical line for each number. Callers dial the DID number directly, bypassing the receptionist or auto-attendant.

In VoIP environments, DIDs are virtual numbers delivered over SIP trunks. This makes it easy to provision local, toll-free, or international numbers for any user, regardless of their physical location.

DID numbers enable CSPs to offer competitive numbering plans to business customers. Combined with number porting, subscribers can keep existing numbers when switching to a VoIP-based softphone solution.