Splicing PS/2 mice together

[gmorse]

I'm using Dos 7.1 and AdvanceMame, but for some reason I can't get the serial port to work on my Mobo, so I'm pretty much stuck using a single ps/2 mouse port.  I decided to use a DPDT switch to swap between my trackball and spinner, so I went and wired the clock and data line of each to the switch and spliced the power and ground directly together (the spinner mouse also had a drain wire, so I attached that to the case line, but left the trackball out of the loop).  Here's what's happening.    If I boot up with the spinner selected, I can swap back and forth between the spinner and trackball as many times as I want.  If I boot up with the trackball selected though, I can't get the spinner to work.  Any thoughts from the gurus out there why this would happen?  The Spinner is based off a Logitech mouse and the trackball a Microsoft.  What if I splice the clock lines directly together and only have the data lines attached to the switch?

[u_rebelscum]

I bet what's happening is your MS hack negotiates, on bootup, to use a MS "intelliPS/2" protocol, while the logitech hack negotiation leaves it at more standard PS/2 protocol.  Here's a link on laptops and hotplugging mice, but it's closely related with the same basic problem and "solutions".

[gmorse]

Good thought.  I went and changed from using the MS mouse driver to the Logitech one and voila, the swap works now when I boot up with the trackball.  Looks like the Logitech driver probably just defaults everything to a more generic protocol.