6 ft Professional RS422/485 USB Serial Cable Adapter w/ COM Retention Add an RS422 or RS485 serial port to your system through USB; features COM port retention 6 ft Professional RS422/485 USB Serial Cable Adapter with COM Retention USB Serial Adapter / USB to RS232 Serial Adapter / USB to RS485 Serial Adapter / USB Serial Adapter Cable no power outlet required, and no cumbersome AC adapter to carry around USB to Straight-Through RS422/485 Serial Adapter