The HDMI Forum adds to the new HDMI 2.1a specification, in the form of Cable Power. This function should facilitate the use of longer active HDMI cables. The cables are supplied with power directly from the HDMI connection.
The HDMI Forum offers an HDMI power cable in . format HDMI 2.1a specification adjustment† With this feature, active HDMI cables can be powered directly from an HDMI connection, without the need to connect a separate power cable. The HDMI Forum argues that this should simplify the use of active HDMI cables. The feature allows cables to draw up to 300mA at 5V from an HDMI connection.
To use this feature, a cable and “source device” that support the HDMI power cable are required. HDMI Power Cables also receive a separate power connector for use with devices that are not compatible with this feature. According to the HDMI Forum, these will be USB-C or USB-Micro-B connections.
Active HDMI cables are primarily used to allow for longer cable lengths. With passive cables of certain lengths, stability issues can occur due to signal loss. An HDMI power cable should make using active HDMI cables as easy as connecting passive cables.
