Derwent Classification System: Communications

Covers telecommunications, audio and video equipment, telemetry/telecontrol and radar, aviation, marine and military systems where electrical details are included.

W01 Telephone and Data Transmission Systems (H04L, M, Q) Error detection and correction. Code conversion. Synchronising. Secret data communication. Data networks (LAN, WAN, etc). ISDN. Baseband and broadband data transmission. Exchanges, call metering, test equipment, equipment racks. Subscriber equipment, cordless and cellular phones. Telephone line and cable installation.
W02 Broadcasting, Radio and Line Transmission Systems (H01P, Q, H04, H04K) Aerials, waveguides, resonators and other distributed constant components. Transmitters, transceivers, transponders. Communication receivers. Line transmission systems. Radio systems, including diversity, relay, mobile (including cellular). Optical and ultrasonic wave transmission systems. Spread Spectrum communication. Secret communication, jamming. Facsimile. TV systems, including colour, stereoscopic, cable, subscription, satellite and high definition. Stereophonic broadcast systems.
W03 TV and Broadcast Radio Receivers (H04) AM/FM/SW radio receivers, car radios. TV receivers. Teletext, high definition, satellite, stereophonic. Remote control. Audio amplifiers. AV systems and interconnection.
W04 Audio/Video Recording and Systems (G10H, G11B, H04N) Loudspeaker enclosures, cross-over networks. Audio disc recording and reproducing equipment. Audio magnetic tape recording and reproduction. Sound mixers. Electrical musical instruments. Video cameras, camera recorders, electronic still-picture cameras. Studio equipment eg video mixers, special effect apparatus. Projection TV. Video tape and disc recording and reproduction. Video games, karaoke. Electronic educational apparatus. Sports equipment. Speech coding, analysis and synthesis. Antiphase sound cancelling.
W05 Alarms, Signalling, Telemetry and Telecontrol (G08B, C) Burglar and fire alarms. Personal calling arrangements. Paging systems. Signal transmission systems. Home bus systems, vehicle remote control bus systems. Advertising arrangements (electrical aspects).
W06 Aviation, Marine and Radar Systems (G01S) Radar, sonar and lidar. Velocity and depth measuring equipment. Airport control systems. Ship and aircraft control and instrumentation. Flight simulators. Space vehicles, including satellites.
W07 Electrical Military Equipment and Weapons (F41) Target indicating systems. Sighting devices. Missile direction control. Military training equipment. Arming and safety devices.