[3]: §CEC-3.1 For example, a TV remote can also control a digital video recorder and a Blu-ray player.
It is a single-wire bidirectional serial bus that is based on the CENELEC standard AV.link protocol to perform remote control functions.
[3]: §§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.
This allows a device to disable its high-speed HDMI circuitry in sleep mode, but be woken up by CEC.
The bus is an open-collector line, somewhat like I²C, passively pulled up to +3.3 V, and driven low to transmit a bit.
A frame consisting of nothing but the header is a ping which simply checks for the presence of another device.
For example, a user press on a remote control will generate a 3-byte frame: a header byte, a