minicom and the input problem

[soul_ache]

Hi all!

Recently I faced a problem which cannot be solved by myself...
The thing is that when i try to connect to a Cisco router using minicom and a Cisco rollover cable everything is fine and connected (serial port is ttyS0). I can see the output from the router, i.e. selfcheck, image decompressing, booting process, etc... But i cannot send anything to it. There is no response for any key pressed from my keyboard... Seems like there is no output from keyboard to router...
Don't know if I explained everything correctly.
Any help is appreciated, thanks is advanced...

P.S.: i've forgot to mention that everything is fine when i use the usb-serial cable and connect console through it (like /dev/ttyUSB0)