Consumer Electronics Control (CEC) is a feature of HDMI designed to control HDMI connected devices by using only one remote controller; so, individual CEC enabled devices can command and control each other without user intervention, for up to 15 devices.:§CEC-3.1 For example, a television set remote controller can also control a set-top box and a DVD player.
It is a one-wire bidirectional serial bus that is based on the CENELEC standard AV.link protocol to perform remote control functions. CEC wiring is mandatory, although implementation of CEC in a product is optional.(§8.1) It was defined in HDMI Specification 1.0 and updated in HDMI 1.2, HDMI 1.2a and HDMI 1.3a (which added timer and audio commands to the bus).:§§CEC-1.2,CEC-1.3,CEC-3.1,CEC-5 USB to CEC adapters exist that allow a computer to control CEC-enabled devices.