Keywords:
Additional equipment, Blank forms, Characteristics, Circuit networks, Communication equipment, Communication networks, Communication service, Communication technology, Communications, Conformity, Connection lines, Digital, Digital engineering, Digital signals, ETSI, Group communication, Implementation, Information processing, Integrated services digital network, Interfaces, Interfaces (data processing), ISDN, Line connections, PICS, PIXIT, Protocols, Radio systems, Service definition, Signal transmission, Signalling systems, Subscriber's systems, Supplementary services, Telecommunication, Telecommunication networks, Telecommunication systems, Telecommunications, Telephone networks, Telephone technics, Terminal devices, Test specifications, Test suites, Testing, Testing requirements, Transmission protocol, Users