HDMI 2.1a specs released: Cable Power option for longer HDMI cables

The future of display connectivity cables is constantly changing, with DisplayPort 2.0 monitors and graphics cards debuting later this year, HDMI 2.1a is also being introduced.

HDMI 2.1a was recently announced by the HDMI Licensing Administrator, designed to give active cables more power directly from the source device... all without needing additional power cables. This means that cables that are longer than 5M won't have as many issues, especially when driving the full 40Gbps or higher 48Gbps through HDMI 2.1 cables.

The big difference with the new HDMI 2.1a specification: the active cables can only be attached in one direction -- with one end of the cable specifically labeled to attach to the HDMI Source, while the other side will be connected ot the HDMI Sink device. If you hook the cable up in reverse, well, it won't actually work.

• Read more: Fake HDMI 2.1 is now a thing, HDMI licensing body doesn't care at all

HDMI® Cable Power

HDMI 2.1a, Amendment 1 adds a new feature: HDMI Cable Power. With this feature, active HDMI® Cables can now be powered directly from the HDMI Connector, without attaching a separate power cable. This makes attaching and using active HDMI Cables as easy as using passive, wired HDMI Cables. To use the HDMI Cable Power feature, it is necessary to have an HDMI Cable which supports the HDMI Cable Power feature, and also an HDMI Source device which supports the HDMI Cable Power feature. This combination ensures that the active HDMI Cable can safely draw sufficient current from the HDMI Connector to power its internal circuitry.

In the case of the Ultra High Speed HDMI® Cable, performance requirements are so high, it is likely that the only way to meet the Ultra High Speed HDMI requirements in cables longer than a few meters is through powered, active HDMI Cables. Therefore, HDMI Cable Power was added to help support the HDMI 2.1a specification's higher speeds by providing power to those active cables which may need it to function correctly. While active HDMI Cables have previously been used extensively in professional markets, their use will now increase in the home whenever consumers need longer-length Ultra High Speed HDMI Cables.

Connection is the same as attaching an ordinary, "wired" HDMI Cable, except that active cables can only be attached in one direction: One end of the cable is specifically labeled for attachment to the HDMI Source (transmitting) device, and the other end of the cable must be attached to the HDMI Sink (receiving) device. If the cable is attached in reverse, no damage will occur, but the connection will not work.

HDMI Cables with HDMI Cable Power include a separate power connector for use with source devices that do not support the HDMI Cable Power feature. Typically, these connectors will be USB Micro-B or USB Type-C®, but different power connector types may be used. As more and more source devices add support for HDMI Cable Power, these longer cables will deliver convenience in the living room along with reliable, high performance home theater audio video