A entidade que gere a norma HDMI introduziu uma alteração à norma HDMI 2.1, ao criar os novos HDMI Cable Power, novos tipos de cabos que conseguem receber energia adicional através do dispositivo emissor do sinal, por forma a melhorar a qualidade do sinal para garantir o elevado débito da interface, os 48 Gbps, para distâncias superiores a três metros.
Estes cabos terão a aparência de um cabo HDMI tradicional, mas só poderão ser colocados num só sentido, ou seja, as fichas têm a indicação sobre onde ligar ao dispositivo emissor e ao receptor. Por serem visualmente idênticos aos restantes cabos HDMI, estes poderão ser ligados de forma inversa, mas poderá dar-se o caso de estes simplesmente não trabalharem, uma vez que os cabos, ao deixarem de receber energia adicional, como previsto, não conseguem garantir a qualidade do sinal.
Para quem está a pensar em montar um sistema de Home Theater em casa, e os equipamentos desejados (ou já adquiridos) que ainda não sejam compatíveis com a norma, não se preocupe, pois os cabos HDMI com alimentação adicional continuarão a ser comercializados, cabos estes que são essenciais para quem precise de um cabo superior a 5 metros, tendo estes a particularidade de incluírem uma ligação adicional, habitualmente em forma de MicroUSB ou USB-C.
Comunicado HDMI
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.
