Posted by Ray on 20, 2001 at 11:38 AM:
http://www.cc-inc.com/pcmall/shop/detail.asp?dpno=69794
Folks, see the above link for an unusually cheap serial port card (looks like a pricing mistake).
I've ordered a couple to be ready when MAME can support 4 COM ports for 4 trackballs (Atari Football, Rampart, etc.)
Doing some research right now to see how hard it would be to expand MAME support to a total of 4 simultaneous trackballs.
Ray