Antennas; antenna boosters; electrical signal distribution devices, namely, audio signal distributors; earphones; wireless receivers; wireless transmitters; battery chargers; battery chargers for microphones; microphones; radio microphone systems comprising microphones, tuners and receivers; public address systems and instruments; public address and sound system accessories and fittings, namely, microphone stands, speaker stands, microphone cables, speaker cables, connectors, mounting racks, cabinets and installation brackets thereof; infrared audio communication systems comprised of microphones, receivers, transmitters, and photoreceivers; infrared microphones; infrared wireless receivers; infrared wireless transmitters; infrared wireless photoreceivers; amplifiers; electrical controllers for speakers; monitors for audio equipment, namely, operation monitoring equipment for use in public address systems; electrical transformers for telecommunication apparatus; power transformers; audio frequency transformers for public address systems; audio signal processors; audio mixers; cabinets for telecommunication devices and apparatus; cabinets for closed circuit television system devices and apparatus; storage container boxes exclusively for use in racks and cabinets for broadcasting machines and apparatus; blank panels exclusively for use in racks and cabinets for broadcasting machines and apparatus; ventilation panels exclusively for use in racks and cabinets for broadcasting machines and apparatus; sound reproduction apparatus; audio recording and playback devices; cassette players; compact disc players; tape recorders; radios; audio signal transmission and reception devices; programmable timers for use with public address systems and broadcasting machines and apparatus; power distribution boxes for electrical equipment; power supplies; electric control panels for public address systems; audio signal relays for public address systems; audio signal converters; electric impedance meters; attenuators; loudspeakers and associated components, namely, loudspeaker cabinets, speaker drivers, enclosures, audio diaphragms and horns; acoustic diaphragms for loudspeakers; horns for loudspeakers; drivers for loudspeakers; megaphones; network audio transmission and reception devices; network audio devices, namely, sound transmitting apparatus; intercommunication apparatus and their parts and accessories, namely, intercom terminals, telephones, mounting racks, audio transmitters and receivers; intercom exchange machines; intercom terminals; telephone apparatus; telephone transmitters and receivers; conference systems comprising telecommunication devices and apparatus, namely, microphones, transmitters, receivers, and amplifiers; emergency broadcasting equipment, namely, microphones, audio amplifiers, audio signal interfaces, control panels, and power supply units; closed circuit television systems; video signal transmission and reception devices, namely, video transmitters, video receivers, and video signal decoders; audio and video receivers; video signal receivers; electronic video display switching devices; video signal compensation devices for closed circuit television systems, namely, cable compensators; lenses for closed circuit television cameras; electric control panels for the operation of video equipment; electric controllers for video monitoring equipment; closed circuit television cameras; covers for closed circuit television cameras; synchronized video signal transmitting devices; electrical swivel mounts for use with closed circuit television cameras; hard disc drives; digital video recorders; housings for closed circuit television cameras; electric monitoring apparatus; video monitors; electrical signal distribution devices, namely, video signal distributors; video signal converters; network video monitoring devices; installation brackets for telecommunication hardware; installation brackets for sound system devices; installation brackets for closed circuit television system devices; batteries for wireless communication devices; transmitters of electronic signals; receivers of electronic signals; sound transmitting apparatus; sound receiving apparatus; electric installations for the remote control of industrial operations; electric plugs, outlets, jacks and connectors for use with audio and video signals; electric adapters; computer software for configuration and function enhancement of network video monitoring devices and network audio devices recorded on computer media; computer software for setting up and configuring local area networks recorded on computer media; computer software for setting up and configuring wide area networks recorded on computer media; downloadable computer software for configuration and function enhancement of network audio monitoring devices and network audio devices; downloadable computer software for setting up and configuring local area networks; downloadable computer software for setting up and configuring wide area networks; computer software for use in recording, amplifying, reproducing and transmitting sounds; electric cables and wires; audio and video signal cables