HDMI 1.4 introduces a feature called HEC (HDMI Ethernet Channel) The HEC feature uses two pins from the connector: a previously unused pin and the hot plug detect pin.
HDMI Ethernet Channel technology consolidates video, audio, and data streams into a single HDMI cable, and the HEC feature enables IP-based applications over the HDMI cable and provides a bidirectional Ethernet communication at 100 Mbit/s.The physical layer of the Ethernet implementation uses attenuated 100BASE-TX type signals on a single twisted pair for both transmit and receive.
That’s great. It sounds good after reading this blog about What does HDMI cables with ethernet mean?
by anonymous at 22-01-2019