So, what is a HDMI CEC?
CEC stands for Consumer Electronics Control which allows HDMI devices to control each other. Furthermore, it allows user to operate multiple devices with just one remote control. It is possible to command and control up-to ten CEC-enabled devices, that are connected through HDMI. For example, you can use your TV's remote control to control TV, computer (HTPC for example), DVD, AV Receiver and other. CEC-enabled devices can also command and control each other without user intervention, for example, when you power off your TV, it can power off other components, or if you power off your computer/netbook, it can power off your TV if it's connected through HDMI.