Active USB to PS/2 adapter?

[timw4mail]

I'm into retrocomputing, and I like mechanical keyboards.

But sometimes I want to use a modern keyboard (like say, a new Model F) on a computer that doesn't play nice with USB, or with DOS. Is there any kind of adapter that will allow use of non-PS/2 compatible USB keyboards to be used on a computer that only supports PS/2?

[Muirium]

There are a few, as I remember. But I've never needed such a thing so my memory is too vague to give you any names.

Do you want / need programmability? This is just for DOS era PCs? I'm used to using earlier vintage keyboards than that, when the layouts were fundamentally different, so need to be modified in software.

[timw4mail]

There are a few, as I remember. But I've never needed such a thing so my memory is too vague to give you any names.

Do you want / need programmability? This is just for DOS era PCs? I'm used to using earlier vintage keyboards than that, when the layouts were fundamentally different, so need to be modified in software.

No need for programmability, just make a USB keyboard speak PS/2 (over PS/2 connector).

[Muirium]

Eminently doable then. It's certainly been done. Let me see if I can find something…

Edit:
Looking around for "reverse" converters, I'm finding nothing. Guess I've false memories after all.

Hasu makes a bunch of great converters (all very programmable, which is why some of us love them) but none that go from modern USB keyboards to PS/2 only hosts. Stack Overflow has a thread you may have already read, summing up the opinion you might find from us here: how about getting one nice vintage keyboard? Look on the bright side: at least you've got a perfectly good excuse!

[timw4mail]

Stack Overflow has a thread you may have already read, summing up the opinion you might find from us here: how about getting one nice vintage keyboard? Look on the bright side: at least you've got a perfectly good excuse!

I have some nice vintage keyboards, and some modern boards that also speak PS/2. I would really like to be able to use my "New Model F" with an old computer, though... I guess I could use my F AT, but I don't think I'll do as well with DOS games with the AT layout.

[Muirium]

Ah right, my bad. So much reading of my searches that I’d forgotten the details of your situation.

Can see why you want this now!

The Model F remake uses a programmable controller, compatible with several firmwares. None of those are PS/2 native, to my knowledge. Could someone write a PS/2 native firmware so that cheapo passive converters would work? Dunno. Sounds a whole lot of effort at the very least.

[Palatino]

I hit a similar dead end when I was looking for a USB to PS2 cable. My plan was to then plug this into my Orihalcon PS2 to USB Soarers converter to enable me to reprogram a modern keyboard how I liked. Never did find a suitable cable out there - I hope it exists or can be made.

[Polecat]

I ran into a similar roadblock trying to get a working USB port on a Win95 box. Win95 supposedly came "with USB support", but that was for a very limited set of hardware items. Plug and play USB didn't really exist until Win98, and I finally gave up on the idea for Win95.

Trying to build hardware and software to implement full USB functionality through a PS/2 port is like trying to shove the cat through the keyhole. If it did work it would be painfully slow. Someone creative could probably build a converter for a specific USB device, and write a software driver to wake it up for a particular OS, but that's way beyond the skillset of most of us. (...and that was the whole point of Plug and Play and USB - so you wouldn't need a software driver for every hardware device!)

[Muirium]

Thing is: Teensies and the like are all USB to host. They’re really intended to make a USB device, which acts as middleman to whatever else you’re cooking up. USB is core to how they work.

When I looked into Bluetoothing my USB only Realforce, I found it’s a hell of a lot more bother than simply hooking up the board to neatly exposed pins. Hasu’s done it, in his USB to USB converters, involving things called “USB shields” which were only very briefly in hobbyist production, years before.

If I were you, Palatino, I’d buy the USB to USB Hasu. It’ll do what you want (unless it’s Soarer specific, in which case you’re still humped). Giving up on Bluetooth myself, Karabiner’s got all my reprogramming needs sorted out for the Realforce, and literally every keyboard I’ve got! That’s the M1 Mac effect, displacing my iPad and making such reprogrammable host-side consistency possible. I even worked out macros.

Doesn’t solve the OP’s problem though at all.

[hellothere]

https://www.ebay.com/itm/143516239687. USB and PC/AT, PS/2 to XT Keyboard adapter. $35. There ya go. They've already sold 73.

[Polecat]

https://www.ebay.com/itm/143516239687. USB and PC/AT, PS/2 to XT Keyboard adapter. $35. There ya go. They've already sold 73.

Neat, but read the listing carefully! That was designed to use an AT (or PS/2) keyboard on an XT (8088) machine, or "a few" USB keyboards they tested with, again on an XT. Won't work on an AT class computer (286/386/486/Pentium/etc.)

edit: This would mostly be useful if you had an XT class computer and an AT-only keyboard, but most AT compatible keyboards had a switch to use in XT mode. The only one I can think of in my collection that doesn't is the Model F AT.

[hellothere]

I reject your reality and substitute my own!

[Polecat]

I reject your reality and substitute my own!

Hey, what's a little reality shift among friends?

[timw4mail]

https://www.ebay.com/itm/143516239687. USB and PC/AT, PS/2 to XT Keyboard adapter. $35. There ya go. They've already sold 73.

So close, and yet...all you need is an XT to PS/2 adapter, plus this one, and maybe it might work...maybe

[Muirium]

An active XT to AT converter, you mean. Were they ever a thing? The keyboards just handled the transition themselves.

Maybe more fruitful to get in touch with whoever designed that thing and convince them of the unintuitive modern demand for a USB to AT/PS2 converter: for our modern retro boards to reconnect with their roots!

[MMcM]

Teensy 3.6 or 4.0 and the USBHost_t36 TeensyDuino library support USB host mode, which is probably the hardest part of this.

[Muirium]

Sounds promising. For those who know what they're doing when it comes to playing as a USB host. (Not me!)

Actually, I'd love a Teensy or the like* which just exposed its own damn USB pins as a break out, to make wiring easier and external sockets (which I much prefer over keyboard tails) less bulky to hook up.

*So long as it runs TMK, QMK, Soarer…

[timw4mail]

An active XT to AT converter, you mean. Were they ever a thing? The keyboards just handled the transition themselves.

Are there modern versions from XT to AT, or do those go from XT to USB?

AT and PS/2 are just different connectors with the same protocol, what's another passive adapter is the absurd chain?

[Muirium]

Are there modern versions from XT to AT,

That's what I was asking. I don't think there is. Or vintage ones either. Keyboards just supported both, with a mode switch.

or do those go from XT to USB?

Yes, that. We can convert XT easily with Soarer's and all the other converters. But every one goes to USB.

[Lanrefni]

Sounds promising. For those who know what they're doing when it comes to playing as a USB host. (Not me!)

Actually, I'd love a Teensy or the like* which just exposed its own damn USB pins as a break out, to make wiring easier and external sockets (which I much prefer over keyboard tails) less bulky to hook up.

*So long as it runs TMK, QMK, Soarer…

The Elite-C seems to be what you're looking for- wiki/Elite-C

[Muirium]

Thanks. Think I heard of that in passing, before. £17.50 in this part of the world, so like a Teensy 2 back when I was first installing those in everything.

[0100010]

Maybe start here https://github.com/10110111/usb2ps2conv

[Muirium]

Is that your GitHub project? The binary usernames are not identical for natives like you, but meanwhile for the rest of us… spooky!

[timw4mail]

Maybe start here https://github.com/10110111/usb2ps2conv

This sounds promising, but I don't have the knowledge to source parts for that...plus a case...

Overall the best partial solution, I'd say, though.

[0100010]

Is that your GitHub project? The binary usernames are not identical for natives like you, but meanwhile for the rest of us… spooky!

Nope, not mine, but I thought about making one before. I have PS2 boards though, so never got around to it.

[0100010]

Maybe start here https://github.com/10110111/usb2ps2conv

This sounds promising, but I don't have the knowledge to source parts for that...plus a case...

Overall the best partial solution, I'd say, though.

Hardware is easy. The ref'd board is in stock at amazon, the rest can come from mouser, digikey, etc. Then spin up a debian VM to collect the software and compile the firmware. Case can be whatever you like really, a hammond enclosure for example.

[Polecat]

That's certainly what's needed. Easy for some, but way out of my comfort zone. If someone here decides to make some of these up they can count me in for one or more. I'd love to be able to use a USB keyboard on my Win95 box.

[timw4mail]

That's certainly what's needed. Easy for some, but way out of my comfort zone. If someone here decides to make some of these up they can count me in for one or more. I'd love to be able to use a USB keyboard on my Win95 box.

It's good to know I'm not the only one!

[timw4mail]

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

[timw4mail]

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.