ETS 300 133-7 : paging systems (PS): european radio message system (ERMES): part 7: operation and maintenance aspects / European Telecommunications Standards Institute
ETS 300 136 : integrated services digital network (ISDN): closed user group (CUG) supplementary service: service description / European Telecommunications Standards Institute
ETS 300 153 : integrated services digital network (ISDN): attachment requirements for terminal equipment to connect to an ISDN using ISDN basic access: (candidate NET3 part 1) / European Telecommunications Standards Institute
ETS 300 156 : integrated services digital network (ISDN): attachment requirements for terminal equipment to connect to an ISDN using ISDN primary rate access: (candidate NET 5) / European Telecommunications Standards Institute