There are no ISA cards that can supply a PS/2 port, because some of the electrical signals that are required are not on the ISA bus. The only way to do it is to assemble a kit and modify your keyboard controller. This can be done to some boards more easily than others. It depends on if your keyboard controller is soldered to the board or not. Some boards even integrated the keyboard controller into the chipset, and in that case you're SOL.

If you do a quick vogons search, you can pull up the development thread on the PS/2 mod. In addition to the hardware, it will normally also require a software driver as well.

Anonymous Coward wrote:

There are no ISA cards that can supply a PS/2 port, because some of the electrical signals that are required are not on the ISA bus.

I picked up this 8-bit ISA card in a recent fleamarket find:

Sure has a PS/2 mouse connector, it's even indicated as such on the board itself. Although since the other connectors are serial and parallel ports it may just integrate a PS/2 to serial port bridge...

There are two different approaches to this:

They are both good reads, but implementation requires some skills, as it seems. 😊

Native PS/2 mouse implementation for 386/486 boards using the keyboard controller (usng onboard KBC)

PS/2 to Microsoft Serialmouse Adapter Converter / Updated First Post / Firmware Update added (a serial to PS/2 converter design)

yawetaG wrote:

I picked up this 8-bit ISA card in a recent fleamarket find: […]
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Anonymous Coward wrote:

There are no ISA cards that can supply a PS/2 port, because some of the electrical signals that are required are not on the ISA bus.

I picked up this 8-bit ISA card in a recent fleamarket find:

IMG_9301.jpg

Sure has a PS/2 mouse connector, it's even indicated as such on the board itself. Although since the other connectors are serial and parallel ports it may just integrate a PS/2 to serial port bridge...

Please take some better photos of the front and back of the card. This card couldn't possibly be fully PS/2 compatible, because 8-bit card edges don't have IRQ12. Perhaps it uses its own special driver.

Well that little 8-bit ISA card sure looks interesting. I wonder if it was meant for some OEM's computer system. Could you provide some high resolution photos of the top/bottom/side? For PS/2 expansion cards, I've only ever seen an 8-bit ISA Microsoft bus mouse card and a PCI USB to PS/2 card.

All the PS/2 mouse implementations I've seen on motherboards have been on IRQ 12. I suppose it would be possible to run the mouse on a lower IRQ, e.g. IRQ 7, if the BIOS was aware of it or there was some driver to set this up.

Have you tested this card yet?

Wouldn't it be easiest to just use an adapter on the serial port? They are very cheap on eBay and I never found one that didn't work.

debs3759 wrote:

Wouldn't it be easiest to just use an adapter on the serial port? They are very cheap on eBay and I never found one that didn't work.

Which adapter do you have in mind?

debs3759 wrote:

Wouldn't it be easiest to just use an adapter on the serial port? They are very cheap on eBay and I never found one that didn't work.

Those are passive adaptors that requires a PS/2 mouse with serial mode capability (read = old). There will be no USB mice for example to have support for serial protocol, although till several years ago, many of them were PS2 compatible.

I thought all adapters were good for all ps2 mice. Guess I've just been lucky 😀

Passive adapters can only work with dual-protocol PS/2-serial mice. Active adapters, like external adapters from vetra systems, and a few others , require power and seem to have substantial lag issues when used with some KVM's. Higher screen resolutions tend to cause some lag as well. For these reasons, it can be beneficial to implement native-PS/2 mouse support to the motherboard. This seems to work for most systems with an external keyboard controller chip. Here's a photo of such an adapter, Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Anonymous Coward wrote:

yawetaG wrote:

I picked up this 8-bit ISA card in a recent fleamarket find: […]
Show full quote

Anonymous Coward wrote:

There are no ISA cards that can supply a PS/2 port, because some of the electrical signals that are required are not on the ISA bus.

I picked up this 8-bit ISA card in a recent fleamarket find:

IMG_9301.jpg

Sure has a PS/2 mouse connector, it's even indicated as such on the board itself. Although since the other connectors are serial and parallel ports it may just integrate a PS/2 to serial port bridge...

Please take some better photos of the front and back of the card. This card couldn't possibly be fully PS/2 compatible, because 8-bit card edges don't have IRQ12. Perhaps it uses its own special driver.

I will upload better pictures tomorrow. The only identifier on the card is a type number "CT-8120S", which gives very few hits on Google (here's the same type of card on a Swiss site: https://www.tutti.ch/de/vi/graubuenden/comput … -8120s/18549739).
AFAIK, the card may originate from the large German electronics mail order company Conrad Electronic, who sold many similar no-name cards back in the mid- to late 1990s.

feipoa wrote:

Well that little 8-bit ISA card sure looks interesting. I wonder if it was meant for some OEM's computer system. Could you provide some high resolution photos of the top/bottom/side? For PS/2 expansion cards, I've only ever seen an 8-bit ISA Microsoft bus mouse card and a PCI USB to PS/2 card.

All the PS/2 mouse implementations I've seen on motherboards have been on IRQ 12. I suppose it would be possible to run the mouse on a lower IRQ, e.g. IRQ 7, if the BIOS was aware of it or there was some driver to set this up.

Better pictures:

Have you tested this card yet?

Unfortunately I don't have a system to test the card on (yet).

Edit: After some googling, I wonder whether this card might be an industrial appliance card for driving a CNC router system - notice how the serial ports are marked as "COM X" and "COM Y"? I can't find much info about the "Twinhead" chip, but there's a company called AXYZ that makes a 6010 twin head router...coincidence? The serial ports would then be used to drive the X/Y position of the router head, the parallel port would handle the remaining communication, and the mouse port would handle input from the user...

That doesn't look at all like a ps/2 port to me. Or is it on the ribbon cables?? The connector I'm seeing is 9 pin.

Ps/2 has 6 pins in a circular pattern with a large rectangular piece of plastic in the center.

BeginnerGuy wrote:

That doesn't look at all like a ps/2 port to me. Or is it on the ribbon cables??

Yeah, you're right 😅 I didn't look at the connector closely enough. The ribbon cables are 2x serial ports.

Dang, that would have been an amazing find if it did do ps/2

It looks like a Microsoft bus mouse port, which must be used with Microsoft 'bus mouse' mice.

Oh, well, that too. 😊 Now where to find a Microsoft bus mouse...

(Twinhead apparently was a PC manufacturer in the late 1980s and early 1990s, so maybe the card comes from one of their systems)

There are plenty of them on Ebay for me (US). feipoa is right, it's for the MS bus mouse.

(snagged from an ebay auction).

Not quite PS/2 though 🙁..

2-button, sometimes 3. Expensive relative to serial mice. I don't think many (any?) KVM's support the bus mouse. I cannot see much advantage over serial mice, except that its a kinds neat thing to have as part of computer history. I sorta recall the sample rate of bus mice being faster (better) than that of serial mice. I feel the best approach is to modify the motherboard's keyboard controller to allow for native ps/2 mice.