I see this: Another PS/2 Mouse ISA (ISA8) card adapter but I'm pretty sure I also saw someone making active PS/2-to-serial converters that work with any PS/2 mice, but can't find the thread now. Another option would be using those old serial optical mice that require a special mousepad to work, there are some NOS on certain auction web site.

Thanks I emailed the make of the first card, hopefully he still has/makes some..

Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Everything else is just savagery

maxtherabbit wrote on 2020-07-02, 14:27:

Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Everything else is just savagery

I didn't read all 18 pages of that thread but it sounds to me like it can end up being a decent sized project depending on your board.

How many people are going to want, much less be able to, modify their motherboard for PS/2 support in addition to possibly having to modify their BIOS?

Quick issues I saw:
1. Must have KBC with PS/2 support
2. Must wire up IRQ12
3. Can mess with Turbo settings... have to figure out which pin on the KBC is used for Turbo since not all boards use the same pin.
4. May have to mod BIOS
5. Have to run at least 1 bodge wire to an ISA slot for IRQ12... more if you don't have an adapter with everything else integrated into it.
6. Adapter height is iffy if the KBC is on the back of the board because it can cause interference with the expansion cards.
7. Your KBC may be soldered.

Seems like a huge hassle to me though it would be really nice if a universal / easily configurable adapter could be made. Gives me an idea but not sure how feasible it would be.

Edit: It seems like it would have also been appropriate to link the thread to the ISA PS/2 mouse adapter card - this is what you want:
viewtopic.php?f=46&t=67488

1) you can swap KBCs
2) ok so what?
3) if you have a physical turbo switch this is a non issue it's only to allow for toggle via keystroke
4) nope, rio444 posted a TSR for that
5) I designed a PCB for it look toward the end of the thread
6) PCB clears that
7) so desolder it like a champion

The PCB doesn't help me in most cases because KBCs are almost always inconveniently located between the ISA connectors and the board edge, meaning a socket and a transposer on top would probably completely block four ISA slots at the very least 🙁 I asked the guy for a PS/2 card, he gave me a price, I'm considering..

appiah4 wrote on 2020-07-02, 21:13:

The PCB doesn't help me in most cases because KBCs are almost always inconveniently located between the ISA connectors and the board edge, meaning a socket and a transposer on top would probably completely block four ISA slots at the very least 🙁 I asked the guy for a PS/2 card, he gave me a price, I'm considering..

"Almost always" is completely untrue. I'd say less than half of 268/386/468 boards locate it there.

The interposer also doesn't block the cards that don't jut down below the top of the isa slot between the slot edge and mounting bracket, which are many

The 3d renderings I posted back then were a worst case for size, you can make the thing much shorter with no sockets and short pin headers. I also recently revised it to allow for more clearance for the metal slot bracket itself in certain KBC orientations. The design files for this revision will be available publicly once it's tested

maxtherabbit wrote on 2020-07-02, 21:09:

1) you can swap KBCs 2) ok so what? 3) if you have a physical turbo switch this is a non issue it's only to allow for toggle vi […]
Show full quote

1) you can swap KBCs
2) ok so what?
3) if you have a physical turbo switch this is a non issue it's only to allow for toggle via keystroke
4) nope, rio444 posted a TSR for that
5) I designed a PCB for it look toward the end of the thread
6) PCB clears that
7) so desolder it like a champion

But there are going to be a lot of people out there that don't want to mess with modifying a board and/or don't have the skills or tools to do the soldering... especially unsoldering the KBC.

That being said, I might mess with doing it that way on systems I build. And I have an idea that would not require unsoldering of the KBC unless you have to swap it.