LinuxQuestions.org - 2009.1 - how to get serial mouse working?

been struggling with a troublesome install of 2009.1 on an
old system. got the major part of the graphics issue working
now, which is to say i have a gui, which i didn't have before.

remaining issue is that the keyboard and mouse, both serial,
which worked fine all through the install, have ceased now
that i have a desktop. the mouse is completely non-functional.
the keyboard is semi-non-functional. some keys work, others
don't.

any suggestions as to how to get this working? this is a clean
install to a new hard drive. the drive i've removed was running
2007.1 and the keyboard and mouse worked fine. xorg.conf appears
to be pretty much the same as it was in 2007.1.

the mouse is actually a logitech marble trackball, three buttons,
no scroll wheel.

edit --- just tried using the old xorg.conf file from my mdv
2007.1 installation. no luck on the mouse but it did configure my
second monitor in my dual monitor setup. hadn't gotten around to
that yet. nobody with any ideas as to how to get the mouse up?

edit --- ok, here's a clue. the serial mouse plugs into a nine-pin
adapter, the kind with two rows of pins: 5 and 4, which plugs into
the back of the computer. this worked in 2007.1. it doesn't in
2009.1. if i unplug the mouse from the adapter and run it directly
to the small, round port on the computer, it works just fine. using
it this way i specify /dev/ttyS0 in xorg.conf. would the 9 pin port
now require a different /dev setting for 2009.1? what might that be?

thanks,
BabaG