Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 11: Supplementary services stage 2; Sub-part 11-24: Call Retention (CRT) (Endorsement of the English version ETS 300392-11-24:2000-09 as German standard)
Edition 2001-08

Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 11: Supplementary services stage 2; Sub-part 13: Call Completion to Busy Subscriber (CCBS) (Endorsement of the English version ETS 300392-11-13:2000 as German standard)
Edition 2000-12

Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 11: Supplementary services stage 2; Sub-part  23: Call Completion on No Reply (CCNR) (Endorsement of the English version ETS 300392-11-23:2000 as German standard)
Edition 2000-12

Private Integrated Services Network (PISN) - Service description, functional capabilities and information flows - Circuit-mode 64 kbit/s bearer services [ISO/IEC 11574 (2000) modified] (Endorsement of the English version EN 300171 V1.3.1 (2003-06) as German standard)
Edition 2004-03

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Generic functional protocol for the support of supplementary services at the "b" service entry point for Virtual Private Network (VPN) applications - Part 1: Protocol specification (Endorsement of the English version EN 301061-1 V 1.2.2 (1998-04) as German standard)
Edition 2000-01

Private Integrated Services Network (PISN) - Inter-exchange signalling protocol; Call transfer supplementary service for the VPN "b" service entry point - Part 1: Test Suite Structure and Test Purposes (TSS&TP) specification (Endorsement of the English version EN 301490-1 V 1.1.2 (2000-12) as German standard)
Edition 2001-05

Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 11: Supplementary services stage 2; Sub-Part 7: Short Number Addressing (SNA) (Endorsement of the English version ETS 300392-11-7:2000 as German standard)
Edition 2000-12

Private Integrated Services Network (PISN) - Specification, functional model and information flows - Call offer supplementary service [ISO/IEC 14841 (1996) modified] (Endorsement of the English version EN 300361 V1.3.1 (2003-06) as German standard)
Edition 2004-03

Private Integrated Services Network (PISN) - Specification, functional model and information flows - Do not disturb and do not disturb override supplementary services [ISO/IEC 14842 (1996) modified] (Endorsement of the English version EN 300363 V1.3.1 (2003-06) as German standard)
Edition 2004-03

Terrestrial Trunked Radio (TETRA) - Voice plus Data (V+D) - Part 9: General requirements for supplementary services (Endorsement of the English version EN 300 392-9 V1.7.1 (2020-04) as a German standard)
Edition 2020-07