DB25-USB is a USB parallel port adapter. When audio switches SWF12, SWM12 and SWU12 are used, please provide DB25-USB adapter kit at the same time. It contains DB25 cable from L-COM Company of the United States, which can effectively restrain interference during parallel data transmission. DB25-USB, as a switching bridge, plays an important role in connecting computers, audio analyzers and SW12 series audio switches.