Integrated Services Digital Network (ISDN) - Closed User Group (CUG) supplementary service; Digital Subscriber Signalling System No. one (DSS1) protocol - Part 1: Protocol specification (Endorsement of the English version EN 300138-1 V 1.3.4 (1998-06) as German standard)
Edition 2000-01

Integrated Services Digital Network (ISDN) - Closed User Group (CUG) supplementary service - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 2: Protocol Implementation Conformance Statement (PICS) proforma specification (Endorsement of the English version EN 300138-2 V 1.3.4 (1998-06) as German standard)
Edition 2000-01

Integrated Services Digital Network (ISDN) - Closed User Group (CUG) supplementary service - Digital Subscriber Signalling System No. one (DSS1) protocol - Part 3: Test Suite Structure and Test Purposes (TSS&TP) specification for the user (Endorsement of the English version EN 300138-3 V 1.3.4 (1998-06) as German standard)
Edition 2000-01

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 (Endorsement of the English version EN 300138-4 V 1.4.3 (2000-05) as German standard)
Edition 2000-10

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol; Closed User Group (CUG) supplementary service - Part 5: Test Suite Structure and Test Purposes (TSS&TP) specification for the network (Endorsement of the English version EN 300138-5 V 3.1.1 (2002-04) as German standard)
Edition 2002-12

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol; Closed User Group (CUG) supplementary service - Part 6: Abstract Test Suite (ATS) and partial Protocol Implementation eXtra Information for Testing (PIXIT) proforma specification for the network (Endorsement of the English version EN 300138-6 V 1.5.1 (2002-04) as German Standard)
Edition 2002-12

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); Closed User Group (CUG) supplementary service; service description; english version ETS 300136:1992
Edition 1992-12

Integrated Services Digital Network (ISDN); Closed User Group (CUG) supplementary service; functional capabilities and information flows; english version ETS 300137:1992
Edition 1992-12

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