Integrated Services Digital Network (ISDN) - Call Waiting (CW) supplementary service - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 1: Protocol specification; english version ETS 300058-1:1991
Integrated Services Digital Network (ISDN); Call Waiting (CW) supplementary service - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 1: Protocol specification (Endorsement of the English version EN 300058-1 V 1.2.4 (1998-06) as German standard)— 1 стр.
