The Consumer Electronics Control (CEC) is an AV Link protocol that is used for remote control functions via HDMI.
The CEC feature allows the user to command and control multiple CEC-enabled products with one remote control and for individual CEC-enabled products to command and control each other without user intervention. An example of the latter is to allow the DVD player, when the drawer closes with a disc, to command the TV and the intervening A/V receiver (all with CEC) to power-up, select the appropriate HDMI inputs, and auto-select the proper video mode and audio mode. No remote control command is needed.