Keywords:
Communication technology, Data link system, Data processing, Data transfer, Digital, Digital recording methods, Digital signals, Electrical engineering, Equipment, ETSI, Hierarchy, Information processing, Interfaces (data processing), Multiplex, Multiplexing, Physical layers, Radio engineering, SDH, Specification (approval), Subscriber's station, Synchronous, Telecommunication, Telecommunication networks, Telecommunication systems, Telecommunications, Telephone networks, Transmission characteristics, Transmission systems, Transmission technique, User