26 Jun
2011
26 Jun
'11
10:11 a.m.
Does anyone have the pinout for the cable that goes from a DEC LK250
keyboard to an AT DIN or PS/2 keyboard plug?
I've got an LK250 that is missing the cable. There's a 6-pin modular
jack (standard not MMJ) on the keyboard and I presume the missing cable
has a mating modular plug on one end and a DIN or PS/2 plug on the other.
I can make one if I can find the pinout...
I don't have the pinout [1] but if nobody repsonds, it whoud lbe possible
to work it out.
The PS/2 and AT keyboard interface uses 4 signals -- +5V, ground, clock,
data. The last 2 are bidirectional data lines, open-collector driven.
If you can recognise any IC in the keyboard you should be able to trace
the connections (using an ohmmeter) back to the 6p6c (or 6p4c,
whatever...) socket to identify the power and ground pins. Assuming you
can then find 2 other pins that are the logic signals, it's safe to try
those both ways round until you get a keyboard that's recognised by the PC.
[1] I think I do have an LK250 somewhere, but it will take soem time to
find it...
-tony