But now that I think of it, I honestly think it was a Firewire port. Does firewire have a black bar over the gold prongs? Mine didn't.. (if it was a Firewire)
Edit, this is my cable.. or at least I think it is. Whatever used to be where the current port is, this fit in it.
http://i21.ebayimg.com/02/i/04/64/13/58_2.JPG