key telephone systems; which is a multiline telephone system designed to provide shared access to outside lines by way of direct line appearance on the station sets, and which consists of key service unit (containing the power supply, processor, external connectors and circuits for lines and stations), key telephone (having an array of buttons to select lines and providing functions of holding, intercom and paging), and boxes of various sizes (providing features as intercom, hands-free answerback, paging, music-on-hold, conferencing and automatic dialing), video door phones, facsimiles machines, computers, blank discs for computers, floppy discs for computers and/or hard discs for computers, printers for computers, monitors, computer workstations which comprise a printed circuit mother board (containing a processor, cache and memory management unit, a floating point processor, a controller, a SCSI bus interface, serial and dudio ports, and a keyboard with mouse), monochrome or color monitor and frame buffer board, internal floppy disk drive, and optional hard disk drive; cellular telephones