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

Integrated Services Digital Network (ISDN). Signalling System n o 7 ISDN User Part (ISUP) version 2 for the international interface . Part 18: completion of Calls to Busy Subscriber (CCBS) supplementary service
Edition 1997-07-01

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network; Inter-exchange signalling protocol; Call offer supplementary service
Edition 2003-04

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network; Specification, functional model and information flows; Call transfer supplementary service
Edition 2003-04

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network; Inter-exchange signalling protocol; Do not disturb and do not disturb override supplementary services
Edition 2003-04

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Specification, functional model and information flows - Wireless Terminal Location Registration supplementary service and Wireless Terminal Information Exchange additional network feature
Edition 1999-11

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network; Inter-exchange signalling protocol; Single Step Call Transfer Supplementary Service
Edition 2003-04

Digital cellular telecommunications system (phase 2). Technical realization of supplementary services (GSM 03.11)
Edition 1996-09-01

Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network; Inter-exchange signalling protocol; Recall supplementary service
Edition 2003-04

Digital cellular telecommunications system (Phase 2). Mobile radio interface layer 3. Supplementary services specification. Formats and coding (GSM 04.80)
Edition 1998-03-01