Joystick settings??

Hi guys

I have bought a USB serial converter to 9 pin, I cannot get my Amiga joystick to work though. Do i need to change settings or ports etc?
Or have I bought the wrong thing alltogether?

i think i have worked it out. IN my desperation to play with the zipstik i have rushed out and bought a data transfer cable by mistake. After searching the forum it appears that a few people have done the same thing!....I will have to wait for the one from Canada to arrive....boooo!