Source : Free On-Line Dictionary of Computing

Automatic Number Identification
     
         (ANI) A service that tells the recipient of a
        telephone call the telephone number of the person making the
        call.  This number can be passed to computer equipment to
        automatically retrieve associated information about the caller,
        i.e. account status, billing records, etc.
     
        See {CTI}.
     
        (1996-12-08)