This plug-n-play cable requires no external power supply. Power is drawn from the 5v signal pin of the source HDMI output. The cable draws less than 0.25w of power from the source. Per HDMI specifications all HDMI compliant sources must at least provide 0.25 watts of power. If a particular source is not able to provide the required power, Hall Research offers 5v power inserter that can be placed between the source and the cable. The power inserter will substitute its own regulated 5v in place of the 5v that comes from the source.