You may need this, USB keyboard and mouse to PS2 interface.

https://github.com/No0ne/ps2x2pico
https://github.com/LimeProgramming/USB-serial-mouse-adapter

I'm using it on my 486, connecting a Logitech wireless keyboard and mouse.

My experience with USB keyboards on DOS is not great. There seems to be a conflict between the keyboard and the PC speaker. Any time the PC speaker is beeping, the keyboard is ignored. If you play a PC speaker game (e.g. Keen 1), gameplay will be ruined. If a game is playing continuous music via the PC speaker, you're effectively locked out of pressing any keys on the keyboard.

A PS2 connection doesn't have such issues onviously. Thus, I also recommend and external conversion device to convert USB to PS2 instead of using the mobo's USB (dunno if extension cards also suffer from the same issue).

wbahnassi wrote on 2024-01-29, 10:27:

My experience with USB keyboards on DOS is not great.

I agree.

1) USB 1.0 was touchy. Hard to predict what would and what wouldn't work. The drivers were often a hot mess. Crashes while hot plugging devices were not unheard of. So that's the baseline that the OP is working with.

2) Next you have your motherboard BIOS. DOS accesses the keyboard through the INT 16 BIOS call. My experience was that finding a BIOS with good USB Keyboard support was rare before 2000. Sometimes one keyboard would work and another one wouldn't. Sometimes the USB keyboard would work in DOS, but could not be used in the BIOS configuration screens, so you needed a PS/2 keyboard to enable USB support. BIOS support for USB add-in boards was pretty much unheard of, so if you find a nice PCI add in board, your BIOS is unlikely to find it. Maybe there were PCI USB cards that come with improved keyboard BIOS via Option Roms. Seems possible but I have not seen that.

3) Then there's hibernation issues. It's not uncommon to see PS/2 - USB devices that don't reinitialize correctly after coming out of hibernation. Easy enough to disable hibernation for retro computers though.

So yeah, it's a minefield of problems. Overcoming them all requires some luck.

Thanks everybody for the information!

It sounds like if I want a socket 7 PC (ie. Pentium 233 MMX) then I need to use PS/2 (and an active adapter for USB keyboard/mice).

sofakng wrote on 2024-01-29, 04:18:

I'm using an IBM PC 350 that includes two USB 1.0 ports but they seem a bit useless. USB keyboards and mice don't work in the BIOS or DOS (ie. no PS/2 emulation).

Are there any ISA or PCI cards that will support a USB keyboard and mouse and allow me to control both the BIOS and work in DOS (for games, etc) ?

It’s kind of the other way around you need a usb keyboard that supports ps/2 protocol and a ps/2 passive adapter

sofakng wrote on 2024-01-29, 14:50:

Thanks everybody for the information!

It sounds like if I want a socket 7 PC (ie. Pentium 233 MMX) then I need to use PS/2 (and an active adapter for USB keyboard/mice).

You can easily get this using a 430TX based chipset board. I've used several with USB keyboards and all of them worked flawlessly.

Intel improved USB support by a lot on their PIIX4 southbridges (used in 430TX or mytical 440BX, for example).