Sorry I do not understand what TX and RX stand for. If you are trying to connect your GPS from the CFX750 to another computer, I suggest to contact your Trimble Dealer for the hardware and output settings for the CFX750 to transfer the GPS into another computer. If you are the Trimble Dealer, then please contact Trimble Hardware Support for additional help. Thanks so much.
Farm Works Mobile will require the NMEA data strings to be able to log data, if this helps.