Digital cellular telecommunications system (Phase 2) - Closed User Group (CUG) supplementary services - Stage 1 (Endorsement of the English version ETS 300518:1996-05 as German standard)
Edition 2001-04

European digital cellular telecommunications system (Phase 2) - Closed User Group (CUG) supplementary services - Stage 2; English version ETS 300546:1996
Edition 1996-08

Digital cellular telecommunications system (Phase 2) - Closed User Group (CUG) supplementary services - Stage 3 (Endorsement of the English version ETS 300569:1996-11 as German standard)
Edition 2001-04

Radio Equipment and Systems (RES) - Digital Enhanced Cordless Telecommunications (DECT); Data service profile (DSP) - Generic data link service for closed user groups (service type C, class 1); English Version ETS 300699:1996
Edition 1998-06

Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. two (DSS2) protocol - Closed User Group (CUG) supplementary service - Part 1: Protocol specification (ITU-T Q.2955.1:1996, modified) (Endorsement of the English version ETS 300770-1:1998 as German standard)
Edition 2000-01

Broadband Integrated Services Digital Network (B-ISDN) - Digital Subscriber Signalling System No. two (DSS2) protocol; closed User Group (CUG) supplementary service - Part 2: Protocol Implementation Conformance Statement (PICS) proforma specification (Endorsement of the English version ETS 300770-2:1998 as German standard)
Edition 2000-01

Integrated Services Digital Network (ISDN). Closed user group (cug) supplementary service. Service description
Edition 1995-04-01

Integrated Services Digital Network (ISDN). Closed user group (CUG). Supplementary service. Functional capabilities and information flows
Edition 1994-12-01

Integrated Services Digital Network (ISDN) - Closed User Group (CUG) supplementary service - Digital Subscriber Signalling System No one (DSS1) protocol - Part 1: protocol specification
Edition 2001-05-01

Integrated Services Digital Network (ISDN) - Closer User Group (CUG) supplementary service - Digital Subscriber Signalling System No one (DSS1) protocol - Part 2: Protocol Implementation Conformance Statement (PICS) proforma specification
Edition 2001-04-01