Is there a specific reason you need a PS/2 mouse? Why not just use a 9-pin serial mouse? It would be more era appropriate for a 486 anyway.

Shponglefan wrote on 2024-06-08, 00:06:

Is there a specific reason you need a PS/2 mouse? Why not just use a 9-pin serial mouse? It would be more era appropriate for a 486 anyway.

All of my 486 machines (from pre 1995 even) have ps/2 keyboard and mice ports.

kingcake wrote on 2024-06-08, 01:22:

Shponglefan wrote on 2024-06-08, 00:06:

Is there a specific reason you need a PS/2 mouse? Why not just use a 9-pin serial mouse? It would be more era appropriate for a 486 anyway.

All of my 486 machines (from pre 1995 even) have ps/2 keyboard and mice ports.

I think only one of my socket 3 boards has a PS/2 mouse option, and none of them have PS/2 keyboard ports.

Out of curiosity, I looked up on Retroweb how prevalent PS/2 options were on socket 3 boards.

They have 762 socket 3 boards, of which 275 have PS/2 mouse options and 116 have PS/2 keyboard ports. A lot of the latter seem to be SBC's or LPX layouts.

Shponglefan wrote on 2024-06-08, 01:32:

I think only one of my socket 3 boards has a PS/2 mouse option, and none of them have PS/2 keyboard ports. […]
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kingcake wrote on 2024-06-08, 01:22:

Shponglefan wrote on 2024-06-08, 00:06:

Is there a specific reason you need a PS/2 mouse? Why not just use a 9-pin serial mouse? It would be more era appropriate for a 486 anyway.

All of my 486 machines (from pre 1995 even) have ps/2 keyboard and mice ports.

I think only one of my socket 3 boards has a PS/2 mouse option, and none of them have PS/2 keyboard ports.

Out of curiosity, I looked up on Retroweb how prevalent PS/2 options were on socket 3 boards.

They have 762 socket 3 boards, of which 275 have PS/2 mouse options and 116 have PS/2 keyboard ports. A lot of the latter seem to be SBC's or LPX layouts.

Agreed, LPX systems aside, a PS/2 mouse ports seems pretty correlated with getting PCI, though there are plenty with PCI and no PS/2 mouse header

jakethompson1 wrote on 2024-06-08, 01:39:

Agreed, LPX systems aside, a PS/2 mouse ports seems pretty correlated with getting PCI, though there are plenty with PCI and no PS/2 mouse header

Interestingly, even among Socket 4 and 5 motherboards a good number lack PS/2 headers or ports.

It seems it took until Socket 7 before they truly became standard.

Yeah my experience with 486 boards is that they don't have PS/2 ports. OEM 486 systems tend to have them though.

The number of board models is meaningless to era appropriateness. What matters is how common they were in the wild, and sales volume determines that.

By 1991 most high volume mass produced computers had ps/2 ports. Imagine how many were in businesses, schools, government, military, etc. To consider only hobbyist and mom and pop boards as the standard is ludicrous.

The fact is 486 machines with ps/2 ports were extremely common and it's completely era appropriate.

Here's a Gateway ad from 1991. Even the freaking 286 budget computers had ps/2 ports at this point.

kingcake wrote on 2024-06-08, 03:00:

The fact is 486 machines with ps/2 ports were extremely common and it's completely era appropriate.

I agree on LPX form factor machines, which were probably even more common than Baby AT. But I disagree that PS/2 mouse was common on Baby AT ISA and VLB 486 boards. So it would depend on whether you got an OEM prebuilt (LPX, which would have PS/2 mouse) or a computer shop custom built (which would be Baby AT and wouldn't).

kingcake wrote on 2024-06-08, 03:00:

The fact is 486 machines with ps/2 ports were extremely common and it's completely era appropriate. […]
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The fact is 486 machines with ps/2 ports were extremely common and it's completely era appropriate.

Here's a Gateway ad from 1991. Even the freaking 286 budget computers had ps/2 ports at this point.

Screenshot 2024-06-07 215239.png
Screenshot 2024-06-07 215219.png

In the ads you posted, the later 386 model and 486 models don't list PS/2 ports. It's curious they are included in the lower-model units? Although I guess this if the earlier models are LPX versus AT/Baby AT in the later models?

Out of curiosity, I started combing through a late 1993 PC Magazine ads. Most of the ads don't list PS/2 ports on their systems.

The retroweb page for the PC-420 mentions PS/2 mouse. The manual however says that pins 2 and 6 of the Mini DIN port are NC. But the bios documentation shows PS/2 mouse support.

This page also says that the Mini-DIN port is combined mouse and keyboard: https://web.archive.org/web/19970327052802/ht … .tw/ipc420.html

If pins 2 and 6 are connected then a Y splitter should work.

florian3 wrote on 2024-06-08, 03:25:

The retroweb page for the PC-420 mentions PS/2 mouse. The manual however says that pins 2 and 6 of the Mini DIN port are NC. But the bios documentation shows PS/2 mouse support.

This page also says that the Mini-DIN port is combined mouse and keyboard: https://web.archive.org/web/19970327052802/ht … .tw/ipc420.html

If pins 2 and 6 are connected then a Y splitter should work.

The M1489/M1487 datasheet suggests that PS/2 mouse would require an external KBC, so I don't see how.

jakethompson1 wrote on 2024-06-08, 03:31:

florian3 wrote on 2024-06-08, 03:25:

The retroweb page for the PC-420 mentions PS/2 mouse. The manual however says that pins 2 and 6 of the Mini DIN port are NC. But the bios documentation shows PS/2 mouse support.

This page also says that the Mini-DIN port is combined mouse and keyboard: https://web.archive.org/web/19970327052802/ht … .tw/ipc420.html

If pins 2 and 6 are connected then a Y splitter should work.

The M1489/M1487 datasheet suggests that PS/2 mouse would require an external KBC, so I don't see how.

Yeah I agree. Then probably the manual is right.

Thank you everyone for your input - in the end I did end up using a PS/2 mouse with a 9pin serial adapter, not really the way I wanted to do it, but it works.

I also got the case finished with some help - and I think it turned out pretty good

I want to still find a set of Roland Speakers for it in Black and maybe an Orpheus II LT sound card with the MIDI module.

Cooper