Dialed Number Identification Service (DNIS) is a service offered by telecommunications companies to corporate clients which identifies the originally dialed telephone number of an inbound call.
For DNIS service, the telephone company sends a sequence of typically four to ten digits during call setup.
[1] Direct inward dial (DID) service also provides DNIS.
For example, a company may have a different toll-free telephone number for each product line it sells, or for multilingual customer support.
For interactive voice response (IVR) systems, DNIS is used as routing information for dispatching purposes, to determine which script or service should be activated based on the number that was dialed to reach the IVR platform.