The current NION manual, version 1.4.3.0, shows incorrect information for the TX and RX pins on the RS-232 serial port:
http://www.peaveyoxford.com/KC/3721.htm
Here is the correct information:
Pin 2 - TX data
Pin 3 - RX data
Note: Transmit (TX) and Receive (RX) are from the point of view of the NION.
Andy.