Integrated Services Digital Network (ISDN) - Three-party (3PTY) supplementary service - Digital Subscriber Signalling System No. 1 (DSS1) protocol - Part 1: Protocol specification; English version ETS 300188-1:1993
Integrated Services Digital Network (ISDN) - Three-party (3PTY) supplementary service - Digital Subscriber Signalling System No. 1 (DSS1) protocol - Part 1: Protocol specification (Endorsement of the English version EN 300188-1 V 1.2.4 (1998-06) as German standard)— 1 стр.
