Best Seller | Tripp Lite 2-Port RS-422/RS-485 USB to Serial FTDI Adapter with COM Retention (USB-B to DB9 F/M) Connects Up to Two 9-Pin Serial Devices to Your Computer Laptop or Tablet s USB-A Port This USB to serial converter turns your computer s USB port into two DB9 ports capable of connecting RS-422 and RS-485 serial devices such as modems handheld... more | | $72.42 FREE shipping go to store |