The Free On-line Dictionary of Computing (30 December 2018):

Dialled Number Identification Service
DNIS

    (DNIS) A service that tells the recipient of
   a telephone call the telephone number dialled by the person
   making the call.  It is used by call centres hosting multiple
   numbers, voicemail systems and ISPs offering shared dial-in
   services.

   Compare ANI, Caller ID.

   (2005-02-09)