EN 301 002-4 : 1.2.1

INTEGRATED SERVICES DIGITAL NETWORK (ISDN); SECURITY TOOLS (SET) PROCEDURES; 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

European Telecommunications Standards Institute