PS2 to USB 1.0 (not 1.1 or 2.0) adapter?

[IBM Portable PC]

I have a system which will only work with USB 1.0 keyboards. I’ve tried several PS2 to USB 1.1 and 2 adapters without success, does anyone have any suggestions?

Amongst those I’ve tried are the; so called Bluebox, Aten, Belkin, Insteon, DeLock and Lindy adapters.

I’m considering the ConnectPro and KingWin adapters...

[hasu]

what's  the system actually if I may ask? And which os do you use on it and what does the os say anything in log file?

Assuming that you have "USB 1.0 keyboard" to test the USB ports on the system, can I ask model number of the keyboard? I'm so curious because I never seen keyboard like that.

[IBM Portable PC]

A Raspberry Pi when setting kernel parameter dwc_otg.speed=1, which limits the USB ports to 12MbS. This helps some USB sound cards work correctly. The only USB keyboard I’ve found that will then work, and many have tried to find others, is an old Ortek Eagle Touch which I suspect is USB 1.0.

[Findecanor]

Maybe you could build your own, with the open-source TMK firmware  and hack it, just downgrading the USB version in the device descriptor.
That firmware I linked is for the ATmega32u4 microcontroller, which is found in the Teensy 2.0 and Arduino Pro Micro.

There should be no difference between USB 1.1 and later protocols when it comes to the HID class protocol, which is used for keyboards.
However, I have not been able to find any good description of what the differences are between USB 1.0 and USB 1.1, or if there are any versions of HID below 1.11 but the latter might not matter.
I suspect that the 1.1 revision could be mostly about compliance to a better defined set of the same specifications.  I have found conflicting information about the highest speed of USB 1.0: if it supports "Full Speed" (12 Mb/s) or not. Maybe "Full Speed" was considered an extension in USB 1.0 and compulsory in 1.1.
I think the firmware I linked to does not support anything else than Full Speed but I know the microcontroller itself supports low speed, so maybe that could be hacked as well but I think it is plausible that that is not necessary.

[IBM Portable PC]

Maybe you could build your own, with the open-source TMK firmware  and hack it, just downgrading the USB version in the device descriptor.
That firmware I linked is for the ATmega32u4 microcontroller, which is found in the Teensy 2.0 and Arduino Pro Micro.

There should be no difference between USB 1.1 and later protocols when it comes to the HID class protocol, which is used for keyboards.
However, I have not been able to find any good description of what the differences are between USB 1.0 and USB 1.1, or if there are any versions of HID below 1.11 but the latter might not matter.
I suspect that the 1.1 revision could be mostly about compliance to a better defined set of the same specifications.  I have found conflicting information about the highest speed of USB 1.0: if it supports "Full Speed" (12 Mb/s) or not. Maybe "Full Speed" was considered an extension in USB 1.0 and compulsory in 1.1.
I think the firmware I linked to does not support anything else than Full Speed but I know the microcontroller itself supports low speed, so maybe that could be hacked as well but I think it is plausible that that is not necessary.

Interesting, however, I don’t have that much time to invest in this. I’m trying a few more active PS2 to USB adapters......

[IBM Portable PC]

Can anyone suggest the brand/model etc of any PS2 to USB adapters which have been on the market since USB first appeared?

[ramon0xff]

Have you considered PS/2 to Bluetooth (I think the Pi > 3B supports it)?
Or even *this*: https://hackaday.io/project/9922-ps2pi