Active USB to PS/2 adapter?

[Muirium]

After some unrelated wiki searching (wiki/Converter), it appears there does exist a commercial model, which seems to still be for sale, and it also supports usb mice: http://www.vetra.com/327Utext.html

Well, apparently it's not still for sale. According the Vetra, it is "up for a redesign", with no timeline, but that they would contact me when it's available

The quest continues, I guess.

Up for a redesign… TO THE NEXT DIMENSION!

The mainstream market for these must have died 20 years ago. Our modern use case is nerdy with a capital SCSI terminator…

[timw4mail]

Up for a redesign… TO THE NEXT DIMENSION!

The mainstream market for these must have died 20 years ago. Our modern use case is nerdy with a capital SCSI terminator…

Glances at K6-2 AT tower (under the desk) with SCSI 5-cd changer and SCSI DVD drive

[Findecanor]

If an ATmega32u4's USART can be used for PS/2 in from a keyboard then it could probably be used for PS/2 out to a host as well. Someone just has to program it.
BTW, the ATmega32u2 also allows direct MCU output to the D+/D- pins, thus supporting PS/2 over the USB port (and a passive adaptor) if the code does proper timing, which isn't as easy though.

Wasn't there also a really early Korean keyboard controller that did PS/2 only? Maybe that one's firmware was closed source though...
Otherwise, maybe that one's source could be combined with the USB host code from TMK's USB-to-USB converter. It could depend on timers and interrupts and stuff... and if input and output would have to fight for MCU time.

[Muirium]

Someone just has to program it.

Is that the same Someone who’s always whispering to everyone that they’re going to rewrite the wiki, top to bottom? Busy fella.

[retrofitit]

That wiki has very outdated info.

[SK-8K]

It won't work with a Model F, but I found a modern PS/2 keyboard controller IC that is programmable and has N-key rollover.
https://www.sprintek.com/en/products/ke ... K5126.aspx

So you could do this with a contact-switch based board.
Perhaps someone could find a way to convert the capacitive signals to direct contact signals, but that's beyond my ability.

[timw4mail]

It won't work with a Model F, but I found a modern PS/2 keyboard controller IC that is programmable and has N-key rollover.
https://www.sprintek.com/en/products/ke ... K5126.aspx

So you could do this with a contact-switch based board.
Perhaps someone could find a way to convert the capacitive signals to direct contact signals, but that's beyond my ability.

While interesting, I'm looking for a solution that more generally solves the problem of a USB keyboard on a computer that can't use USB, but can use PS/2.

[Muirium]

Perhaps someone could find a way to convert the capacitive signals to direct contact signals, but that's beyond my ability.

I fear even the living legend that is Someone (Man of Action!) can’t pull off the technically impossible. Capsense isn’t just a flavour of conductive switching. You need to sense each switch’s capacitance directly. Fundamentally different technology.

[0100010]

Saw this today : https://remysharp.com/2021/04/14/buildi ... e-keyboard

[timw4mail]

Assuming that it gets delivered, I did manage to find what seems to be what I'm looking for on Amazon:

"TRIPP LITE Minicom PS2 to USB Converter for KVM Switch"

https://www.amazon.com/gp/product/B0040 ... le_o01_s00

[timw4mail]

Well, the adapter arrived (The Tripp Lite Minicom thing).

So, unfortunately, for keyboards, it only really works with USB keyboards that speak PS/2. With other USB keyboards, it would maybe register a key about once a second, and the mouse would also get really laggy.

On the plus side, it handled every USB mouse I tried.

[gichtl]

ATEN has such a product CV10KM:
https://www.aten.com/global/en/products ... es/cv10km/

It requires additional 5V power (free USB port or dedicated USB power supply), which seams reasonable since PS/2 can deliver only 275mA while (normal) USB can draw up to 500mA.

[Polecat]

I just found this version looking for something unrelated:

https://www.ebay.com/itm/334177901072

Tripp Lite 0DT60002

Probably part of a KVM switch setup?

[timw4mail]

I just found this version looking for something unrelated:

https://www.ebay.com/itm/334177901072

Tripp Lite 0DT60002

Probably part of a KVM switch setup?

Pretty sure that's exactly what I got from Amazon.

[Polecat]

Pretty sure that's exactly what I got from Amazon.

Oops, sorry, I didn't, uh, make the connection.

[timw4mail]

ATEN has such a product CV10KM:
https://www.aten.com/global/en/products ... es/cv10km/

It requires additional 5V power (free USB port or dedicated USB power supply), which seams reasonable since PS/2 can deliver only 275mA while (normal) USB can draw up to 500mA.

Doesn't look like it would be easy to buy, maybe they only accept bulk orders?

[gichtl]

Here in Germany I see no problem to order them

https://www.kabelprofishop.de/nfl32552/ ... erter-0-8m
https://fabesa.de/produkt/aten-cv10km-u ... konverter/
https://www.secomp.de/de_DE/aten-cv10km ... i/14017244

[edlee]

The Tripp Lite 0DT60002 has worked well for me on multiple USB keyboards, including Rosewill RK-9000V2, RK-9000V2 RGB, Redragon Brahma Pro, Bloody B975, and Inland OMK-X keyboards. I use these keyboards with Soarer's converter connected to the Tripp Lite 0DT60002. Two other USB to PS/2 adapters that might work but which I haven't tried are ones that I found on eBay:

Black Box kvusb-ps2

NTI USB-PS2-R

[edlee]

Maybe the issue timw4mail is experiencing with the Tripp Lite 0DT60002 is it isn't getting enough power. I use a custom Soarer's converter with extra 1K Ohm resistors between Clock and +5V and between Data and +5V. You could try to plug the USB keyboard into a powered USB hub and then plug the male end of the powered USB hub into the Tripp Lite 0DT60002.

[timw4mail]

Maybe the issue timw4mail is experiencing with the Tripp Lite 0DT60002 is it isn't getting enough power. I use a custom Soarer's converter with extra 1K Ohm resistors between Clock and +5V and between Data and +5V. You could try to plug the USB keyboard into a powered USB hub and then plug the male end of the powered USB hub into the Tripp Lite 0DT60002.

That might be the case. My Matias click KB Paradise board works with the adapter, and I rather doubt that board has PS/2 compatibility.

[edlee]

I just tried an ABKO K995P V3 keyboard with my Tripp Lite 0DT60002 and Soarer's converter. The keyboard didn't work. It apparently requires too much power.

[Muirium]

Your PS/2 port puts out plenty enough power, I expect. So you could try something sneaky. There's 4 lines after all. Take the power and ground *around* the adapter, so the Teensy gets the power it and the keyboard needs. Branch those two lines to feed things in parallel.

I'm no electrical engineer, mind. If someone reckons this is a bad idea, do tell.