Vincent, The USB interface came with my Sony MZ-R700 MiniDisk which also features a microphone input. It is the Xitel MD-Port DG2, and and connects through an optical TosLink (S/PDIF) to digitally transfer music files from computer to the MD. Nice little box, and fully supported under Linux just as my MidiSport 2x2 MIDI interface, and HP6200c scanner. Frank