Electronic video multiplexer; digital signal processors; computer monitors; video monitors; sound transmitting apparatus; audio switching apparatus; cables for electronic transmission; cables and fibres for the transmission of sounds and images; USB cables; electrical communication machines and instruments; video surveillance apparatus; audio and video receivers; cables for optical signal transmission; video screens; computer peripheral devices; wireless transmitters and receivers; computer network switches; combination video players and recorders; devices for playing sound and image carriers; devices for recording sound and image carriers.