OK. I'm not 100% sure how the "PC interface" works on either the RS232 board (which is the one I have) or the USB board. But I suspect the interface is the same as the UART interface and if that's the case using the serial terminal might not be the right tool since you want to send and receive "raw" data while a terminal program such as the serial terminal is designed to send/receive ASCII. You CAN send "raw" data with it but when whatever it receives it tries to interpret as ASCII which probably won't work.

I know there auxillary data outputs which can be re-directed to various interfaces. Perhaps you need to reconfigure those in order to get it to output data to the "PC interface".

/Henrik.