How to connect PC Rs232 to CIII FPGA Pins?

JTAG uses 4 signal (the other pins being Vcc,GND or NC) which are dedicated pins on the fpga. AFAIK you cannot use them as general purpose pins in your design.

Surely jtag can emulate a serial port, which is what the Quartus debugger does: but in this case I think you need a specific hardware (USB blaster or similar) and a pc side driver/software in addition to the jtag serial port module in the fpga; your external converter board is far from being enough.

For a RS232 interface (say UART, since rs232 are actually the phy signal levels) you simply need a single input and a single output signal, provided you don't require flow control, which would add one more input and one more output.

If you can wire these two pins out of your board, this is quite easy to implement.

Regards

Cris