Abstract: A method is disclosed for processing call data among telephone switching offices and a remotely situated data base system for deriving call service information needed to complete special service calls, such as INward WATS (Wide Area Telephone Service) calls to a destination specified by the derived information. A network of local and toll offices compiles a special service call message including a caller dialed 800 number and an originating area code for the INWATS service and then transmits that message to the data base system over CCIS (Common Channel Interoffice Signalling) facilities including signal transfer systems. At the data base, the message is translated into a directory-unlisted number identifying an INWATS customer station designated to serve the call.