DIN ETS 300052-4:1998-04
Отменен
Integrated Services Digital Network (ISDN) - Multiple Subscriber Number (MSN) supplementary service; Digital Subscriber Signalling System No. one (DSS1) protocol - Part 4: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification for the user; English version ETS 300052-4:1997
