Add a null modem rs232 serial port to your laptop or desktop computer through usb the icusb232ftn ftdi usb to null modem serial adapter cable 1 port converts an available usb 11 or 20 port into an rs232 null modem serial db9 port solving dcedte conflicts directly without requiring additional cross wired serial cables or adapters this compact adapter features com retention allowing the same com port value to automatically be re assigned to the port if the cable is disconnected and re