I have not tried that excat combination ... but
I have hook up the serial port of the main unit to the radio RRC (DB9) via RRC Com2 mode 4 9600,8,1,N (same setting on com2 control site)
At control site im using a microHam (USB->Serial interface) to map to a serial port at my computer.
I can then start any program to communicate with the radio at the control site vis the cat interface.