Integrated Services Digital Network (ISDN) - Signalling System No. 7 (SS7); ISDN User Part (ISUP) version 4 for the international interface - Part 9: Closed User Group (CUG) supplementary service (ITU-T Recommendation Q.735, clause 1 (1993), modified) (Endorsement of the English version EN 300356-9 V 4.1.2 (2001-07) as German standard)
Edition 2002-01

Integrated Services Digital Network (ISDN) - Signalling System No.7 (SS7) - ISDN User Part (ISUP) version 4 for the international interface - Part 9: Closed User Group (CUG) supplementary service [ITU-T Recommendation Q.735, clause 1 (1993), modified]
Edition 2001-11-01

Broadband Integrated Services Digital Network (B-ISDN) - Signalling system No. 7 - Interworking between Broadband ISDN User Part (B-ISUP) and narrowband ISDN User Part (ISUP) (ITU-T Q.2660:1995, modified); English version ETS 300496:1997
Edition 1998-02

Broadband Integrated Services Digital Network (B-ISDN) - Signalling System No. 7 - B-ISDN User Part (B-ISUP) Capability Set 1 (CS1) - Supplementary services (ITU-T Q.2730:1995, modified); English version ETS 300657:1997
Edition 1998-02

Broadband Integrated Services Digital Network (B-ISDN) - Signalling System No. 7 - B-ISDN User Part (B-ISUP) Capability Set 1 (CS1); Basic services (ITU-T Q.2761 to Q.2764:1995, modified); English version ETS 300656:1997
Edition 1998-02