DID (Direct Inward Dialing) — Direct Inward Dialing
What is DID (Direct Inward Dialing)?
A DID (Direct Inward Dialing) number is a phone number a carrier assigns directly to an extension, ring group, or IVR menu on a business's PBX or cloud phone system, so an external caller reaches that destination without going through a receptionist first. Businesses provision blocks of DID numbers so each employee, department, or automated menu option gets its own dialable number while every call still terminates over the same underlying SIP trunk.
More detail
DID numbers are typically purchased in blocks from a carrier or number provider and mapped in the phone system's dial plan to a specific extension, ring group, or IVR destination.
Unlike a single shared main line, DIDs let external callers reach an individual extension directly, while the PBX still handles internal transfer, hold, and voicemail for that same number.
Frequently asked
- How is a DID number different from a regular phone number?
- It isn't functionally different as dialed by a caller — the difference is administrative: a DID is simply a number a carrier hands off directly to a specific PBX destination instead of to one shared main line.
- Do I need a separate SIP trunk for every DID number?
- No. A single SIP trunk carries many DID numbers at once — the trunk provides the call channels, while each DID number is just mapped to a destination in the dial plan.
See also
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