rs232 connection receive & transmit nothing on de2 board

Hi, I need to implement RS232 on DE2 board. I had connected my pin RXD as C25 & TXD as D25 as specified by the board. But I can't detected any startbit received on my rs232 RXD pin. Initially, I suspected my code problem. But after I made a simple code to detect ANY RXD = '0' signal (I tried to detect RXD = '0' at both speed of 50MHz & 115200 baud rate), yet it still not able to detect any RXD = '0' occurred.

Is there any other bit I need to set or any connector I need to short or whatever configuration I need to do with the board (which I did not see any of them when I glanced through DE2 doc).

p.s:The RS232 is working fine from PC side (I tested with loopback test (RS-232 loopback test).) I also tried to do very simple stuff to directly connect my RXD input to TXD output (emulate a loopback test) & the PC detects nothing in return too :(

Thanks!