Have an 8-Port Belkin KVM. 2 of the ports I have hooked up to PC's that use serial mice. I have the same belkin db-9 female to male cable going from the PC to the KVM Switch in both ports. The KVM then electronically switches to allow the PS/2 mouse hooked up in the console port to work.

For the Pentium 1 machine running Windows 95, the system boots up, starts to load Windows, you hear the KVM switch its modes and the PS/2 mouse works fine once in Windows

For the 486 DOS / Win 3.11 machine, the system boots up, loads DOS, loads CuteMouse software, you hear the KVM Switch its modes but when you go into Edit mode in DOS and move the mouse, the cursor just shoots to the bottom left of the screen and doesnt move from there... or if you go into WIn 3.11, there is no mouse to use at all...

Trying to figure out why the mouse isnt working for the 486 machine. Plugging a serial mouse directly into the machine works fine.