Apparatus and instruments for checking, supervision, monitoring, viewing, recording, transmission, processing or reproduction of sound and images and apparatus and instruments for controlling and transmitting video, audio and communication signals and information via wires or wireless means, namely, video-audio signal distributors, video-audio signal switchers and matrix switchers, video and audio enhancers, video and audio processors, RF processors, special effects generators, video encoders and decoders, electronic video signal scalers, color processors, audio signal defect correctors, video line amplifiers, video screen splitters and video time base signal delay correctors, video-standard converters; scan converters; video standard converters; video time base correctors; computer genlock (generator locking) equipment, namely, genlock (generator locking) device for graphics and text overlay; computer controlled video equipment, namely, video matrix and processing control panels; computer interface products, namely, TTL (transistor-transistor logic) analogue encoders, TTL (transistor-transistor logic) to analogue converters, TTL (transistor-transistor logic) genlock (generator locking) encoder cards; room control devices, namely, electric switch wall plates and table bus bars with infra-red, ethernet, wireless network and controlling devices; audio signal defect correctors; video line amplifiers; twisted pair signal transmitters and receivers; video screen splitters and video time base signal delay correctors; electrical cables and wires; amplifiers; microphones; loudspeakers; centrally-controlled audio-video system comprised of audio amplification providing solutions for the integration of media and control in classrooms, training rooms and presentation rooms, comprising wall or ceiling-mounted multi-media projectors, wall or ceiling audio speakers, computer software for graphics videos, computer hardware for graphics videos, display screens, and optionally, DVD players; display screens; furniture-mounted connection bus featuring a power source, universal power sockets, video, audio, telephone and other network connectors; computer operating software for the aforementioned products; parts and fittings for the aforementioned products