OfficeServ OpenTSP Driver interfaces with the Samsung key telephone system through the TCP/IP system, based on TAPI 2.x/TAPI 3.x, and enables call control and call processing of the Telephony Application Programming Interface(TAPI) service through the TSPI. OfficeServ OpenTSP driver is installed on a PC using the Windows O/S. The TAPI 2.x/TAPI 3.x designed by Microsoft based on the TAPI standard.