IBM 3278 Beamspring to PS/2 controller

[Compgeke]

Something interesting that just showed up on the classiccmp mailing list here, a 3278 (Beamspring) to PS/2 controller\adapter. The interesting part of this one is it isn't a controller replacement, but something that goes on the end of the existing controller.

A link:
http://www.ibmsystem3.nl/IBM3278/

And a couple pictures:

[Halvar]

That's remarkable, thanks for posting.

On the original PS/2 keyboard every key generates a make and a break code.
The 3278 generates only make and break codes for the following keys:
- Shift
- Alt

To me, this means that only the physical Shift and Alt keys can be used as modifiers. That seems like a big disadvantage compared to a replacement controller like xwhatsit's. Not enough Control, literally.

[xwhatsit]

Very cool. Murium posted that up on the Beamspring USB thread. In many ways this is preferrable to the solution I came up with—no need to source silly 3.96mm pitch connectors etc.

In addition, the historian instinct in me appreciates how you're still using the original hardware. Granted with my solution you're not destroying anything, but the original IBM controller then has to sit in an antistatic bag in the cupboard instead of in the keyboard where it rightfully belongs...

I wonder how different the 3278 and 5251-style protocols are? I think they used similar connectors on the PCB, you might just be able to get away with different firmware

Shame about the make and break codes—funny how a lot of those early keyboard protocols didn't bother—but this would be a sweet link in the chain for Soarer's converter!

[Game Theory]

Believe author just posted on Geekhack http://geekhack.org/index.php?topic=51011.0

I prefer the total swap of controller myself because of the programability.