EN 300 138-4 : 1.4.3

INTEGRATED SERVICES DIGITAL NETWORK (ISDN); CLOSED USER GROUP (CUG) 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

European Telecommunications Standards Institute