The icusbaudiomh external usb card lets you add an spdif digital audio output or a standard 35mm analog audio connection to your system through usb by converting a single usb port into an external sound card with microphone connectivity you can conveniently bypass or replace an internal sound card without having to open your computer case the usb dac digital to analog converter provides a built in microphone allowing you to add audio recording capability to your system without the need f