HEC is used primarily for audio control. The Ethernet channel can be used to provide an Internet connection between devices, especially when HDMI devices are used for streaming video or other content from the Internet.
Advantages of HDMI in video surveillance HDMI cables have several advantages that make it superior over some interfaces like DVI and component video, especially in video surveillance systems. HDMI includes all components of both video and audio data in one cable, so there is no need for extra cables.