I'm not Dave, but my list of 2000 Motherboard jumpers sheet shows J200 as
being the jumper that determines how a lightpen will be read. With pins 2
and 3 jumpered (the normal way) the lightpen input is from the FIRE input
of mouse/joyport 2, just like the A500. With pins 1 and 2 jumpered the
input is from mouse/joyport 1, like the A1000. Keith