usb to ps/2 adapter works in one machine, but not another?

[perryh at pluto.rain.com]

Torfinn Ingolfsen <torfinn.ingolfsen at broadpark.no> wrote:
> Many new machines / motherboards today comes with only one
> ps/2 port.  Well, the kvm switches I use still has ps/2 ports.
> Therefore I use adapters that plug into a usb port and gives
> me two ps/2 ports ...  I generally only use one port on these
> - for a mouse.

There may be a simpler solution.  The systems I've seen with only
one ps/2 jack had both the keyboard and the mouse signals wired to
the single jack.  (Quick test:  if it is wired this way it will work
with either a keyboard or a mouse.)  If that's how yours is set up
you can get a Y adapter with one ps/2 plug and two ps/2 jacks, and
not need to deal with USB keyboard or mouse support at all.