INSTALLATION AND MAINTENANCE OF ELECTRONIC SYSTEMS AND DEVICES COMPRISED OF SOUND AMPLIFIERS, ELECTRONIC CONTROLLERS, AUDIO AND VIDEO ELECTRONIC SWITCHERS, ELECTRICAL POWER SUPPLIES, AUDIO FILTERS, AUDIO EQUALIZERS, AUDIO SPEAKERS, ELECTRONIC SOUND TRANSDUCERS, COMPUTER INTERFACE BOARDS, COMPUTERS, AUDIO FREQUENCY ANALYZERS, ELECTRONIC APPARATUS FOR TESTING, NAMELY ARTIFICIAL NOISE GENERATORS, TEST SIGNAL INJECTORS, RESONANT OBJECT LOCATING SENSORS, PHASE CORRECTION SIGNAL INJECTORS AND GRAPHIC ROOM CHARACTERISTICS MAPPING DEVICES, AUDIO SIGNAL GENERATORS, AUDIO SPECTRUM SWEEPERS, REMOTE CONTROLS FOR THE ACTIVATION OF ALARMS, CONTROL OF AUDIO PROGRAM SELECTION, CONTENT, VOLUME AND AUDIO CONTOUR, ACTIVATION OF BUILT-IN TEST FEATURES, CONTROL OF AMPLIFIERS, AND MUSIC SOURCE DEVICES, AUDIO DISTRIBUTION CABLING SYSTEMS, ATTENUATORS, STEREO TUNERS, ANALOG AND DIGITAL TAPE PLAYERS AND RECORDERS, INTERNET INTERFACES, NAMELY BRIDGES, ROUTERS, MUXES, MULTIPLEXERS AND IMPEDANCE MATCHING ADAPTORS, SATELLITE INTERFACES, NAMELY SATELLITE RECEIVERS AND TRANSMITTERS FOR SENDING AND RECEIVING PROGRAM CONTENT AND OPERATIONAL COMMANDS VIA SATELLITE, AUDIO MATRICIES, NAMELY ROUTERS, MUXES, SWITCHERS, MULTIPLEXERS, PATCH PANELS AND SWITCHING PANEL ARRAYS, MODEMS, COMPUTER SOUND CARDS, COMPUTER HARDWARE, AUTOMATIC ELECTRICAL CONTROLS, NAMELY TIMERS, POWER SUPPLIES, SWITCHING RELAYS, SIGNAL ROUTERS, POWER FAILURE OR FAULT SENSING SWITCHING DEVICES, AND MICROPROCESSORS FOR USE IN THE FORMATTING, REPRODUCTION AND TRANSMISSION OF AUDIO AND VIDEO DATA, NAMELY FOR THE FORMATTING, REPRODUCTION AND TRANSMISSION OF MUSIC, PAGING AND VIDEO DATA