If an HDMI accessory device (i.e. switch box, cable booster) does not have a dedicated power supply, is it still compliant and will it work?
An HDMI device that has active electronics should have a provision for external power in order to be compliant (e.g. a receptacle to allow the use of a standard power adapter, sometimes called a power “brick”). Here we are drawing a distinction between “active” devices that actually have some powered electronics, and “passive” devices, such as some switches (more on those later). Some active devices, such as actively powered HDMI cables or in-line signal extender boxes, will by default attempt to power their electronics by taking power from the 5V line (+5V power) available on the HDMI connector. The HDMI specification requires all source devices to provide at least 55mA (milliamps) on the 5V line for the purpose of reading the EDID of a display. While 55mA is not enough current to operate most HDMI accessory devices (which typically require about 100 to 150mA), most source devices on the market today provide significantly more current on the 5V line than the HDMI specification require
Related Questions
- If an HDMI accessory device (i.e. switch box, cable booster) does not have a dedicated power supply, is it still compliant and will it work?
- Does an HDMI accessory device (i.e. switch box, cable booster) need a dedicated power supply to work?
- What happens to my DVR recordings if my digital cable box temporarily loses power?
