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

Telephony Application Programming Interface
TAPI

    (TAPI, or "Telephone Application
   Program Interface") A Windows 95 Application Program
   Interface enabling hardware independent access to telephone
   based communication.  TAPI covers a rather wide area of
   services from initialising the equipment (e.g. a modem) and
   placing a call to voice mail or control of a remote
   computer.

   [Telephone or Telephony?]

   (1995-12-05)