DisplayPort can be used to transmit audio and video simultaneously, although each is optional and can be transmitted without the other. The video signal path can range from six to sixteen bits per color channel, and the audio path can have up to eight channels of 24-bit, 192kHz PCM audio that is uncompressed. A bi-directional, half-duplex auxiliary channel carries device management and device control data for the Main Link, such as VESA EDID, MCCS, and DPMS standards. In addition, the interface is capable of carrying bi-directional USB signals.