IBM LPFK reverse engineering

Ethan Dicks ethan.dicks at
Tue Aug 19 21:04:33 CDT 2008

On Tue, Aug 19, 2008 at 07:48:24PM -0600, Michael B. Brutman wrote:
> IBM LPFK 6094-020 victims ..


> It's been a year, but I finally found what I was looking for.  Which is 
> good because I was about to go mideval on an AIX 4.3 box to get the data 
> that I needed. ;-)  Somebody deep inside the Blue Wall had the docs on a 

Nicely done!
> Here is the quick summary:
> Protocol: 9600,O,8,1 with no handshaking...
> All of this is also written up at 
> for the good of the greater 
> public. 

Thanks for the writeup.  I look forward to trying this out on my LPFKs
when I get home.

The protocol you describe is radically different from the one that
codeninja describes at  My first guess
is that there are two versions of the firmware running around, but is
there any way to confirm that?  Minor variations in IBM part numbers or
what the keyboards were intended to attach to?

In terms of usage, were there overlay cards for different applications, or
how did you tell what keys meant what?  Were the LEDs used in practice
to light up to confirm keypress, or were they used to indicate which
functions were enabled, or what?

I've used dialboxes with graphic workstations in the past, but I've never
worked with a keypad like this.  I'm just trying to get a handle on how
it was used.  I have my own ideas about what to use one for (LCDproc, an
open source project I work on, for example), but I'm just curious why
this keypad has the features it does and how it was originally used.



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