The hdmi minidpusb allows you to connect a computer with mini display port and a spare usb port to a hdmi device such as hd tv the mini displayport transmits the video signal while the usb transmits the audio creating a complete hdmi source specification active adaptor supports mini display port 11a input usb 20 input and hdmi 13b output works by integrating mini display port video source and usb audio source powered by mini display and usb port supports hdmi 225mhz225gbs per channel