IBM LPFK reverse engineering

Michael B. Brutman mbbrutman-cctalk at
Wed Aug 20 23:16:44 CDT 2008

Philip Pemberton wrote:

> It's nice to finally see the LPFK light up :)

Yes, yes indeed ...

> It's probably worth noting that the LPFK doesn't auto-repeat, nor does 
> it send a separate key-up/key-down scan code. Depending on your POV, 
> this is either a good thing or a bad thing :)

I like the simplicity of it.  Press a button, get a byte.  No need to 
worry about key combinations and other silliness that makes decoding the 
PC keyboard so fun.

>> All of this is also written up at 
>> for the good of the greater 
>> public.
> Though in fairness the message you posted here is probably going to be 
> more permanent :)

I was only going to post on the web site, but I knew that some elitist 
snob here would get upset.  So I posted in both places.

(If your blood pressure is rising now, then you are an elitist snob.)

(It's also fun throwing bricks at people who are so easily stirred.)


Back On Topic ...

>> I have a blank overlay and a CADAM overlay that labels the keystrokes. I
>> will probably scan the blank shortly so that people can download and make
>> their own.
> I'll look forward to that. I'm trying to think of a serious use for the 
> LPFK but I'd still like to see what the keypad overlays look like.

I scanned the overlay, cleaned it up and posted it.  Enjoy!

> Interestingly enough, I did a quick search on CADAM and found this -- 
> <>. It seems to be a mini 
> version of the LPFK without the blinkenlites.

Ugh, look at the price!  Kind of expensive for an alternate keyboard 
with custom scan codes.


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