Visit Amazon sites : http://www.amazon.com/gp/product/B0049OJPTU?tag=gallianostore-20<br /><br />StarTech.com 2 Port USB to RS232 RS422 RS485 Serial Adapter with COM Retention ICUSB2324852<br /><br />This single adapter is compatible with any serial device protocol RS232 RS422 and RS485 and even allows mixing protocols for simultaneous communication over both ports <br />COM retention saves the assigned port settings for the device so disconnectingreconnecting is hassle-free <br />USB Powered - no power outlet required and no cumbersome AC adapter to carry around <br />Backwards compatible with USB 11 <br />USB-powered No additional external power adapter required <br />Both ports can function simultaneously with mixed or matched communication protocols
