Transmission of colour video signals over a wire pair

An enterprise KVM system using single twisted pairs to transmit video and data signals is described together with circuitry for the parts of the system and a method of transmitting the signals. The method transmits a video signal and peripheral data over a single twisted pair between a computer and a plurality of peripherals. A sequence 351 of a plurality of analogue video colour signals 352,354,356 with a vertical synchronisation signal 360 following each analogue video signal is transmitted from the computer to the plurality of peripherals. Each analogue video colour signal is a single colour sample of a video frame. Peripheral data is transmitted between the plurality of peripherals and computer during the vertical synchronisation signal transmission periods. The KVM enterprise system comprises a plurality of user stations, each user station including a keyboard, mouse and video display connected to a user interface. A plurality of computers are provided each connected to a dongle and supplying video, keyboard and mouse signals to the dongle. A KVM matrix switch is also included. Each of the dongles is connected to the matrix switch by a respective single twisted pair cable. Each of the user interfaces is connected to the matrix switch by a respective single twisted pair cable. Video signals and keyboard or mouse signals are transmitted via the twisted pair cables between any one of the plurality of computers and any one of the user stations.