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AT/XT Autoswitch keyboards

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nestor

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I recived today a Philips P2814 keyboard that seems to support both XT and AT protocols (it has the standard AT layout but no XT/AT switch).

I plugged it to my IBM 5160XT and it works like a charm, but I can't get it working in a generic Turbo XT clone. I tried some time ago an IBM Model M keyboard from 1992 in this Turbo XT clone and it didn't work, so I assumed that it only supported AT protocol, but... surprise! It also works in the 5160 XT. It has also the autoswitch feature and I didn't know.

My question is, why do these autoswitch keyboards work in the XT and not in the clone?
 
Is it a late-model XT? The 1/10/1986 BIOS version "Added support for the 101-key Enhanced keyboard", in the words of IBM.
 
Some clones come with a keylock a la the AT, and sometimes (emphasis because it goes both ways apparently) the connection for the keylock needs to be shorted with a jumper to unlock the keyboard if you don't have a keylock. In this case, open circuit for the pins, which would happen if you didn't have a keylock, means keyboard is locked. Do you have the manual for the Turbo XT motherboard or can otherwise figure out if it has provisions for a keylock?
 
vwestlife said:
Is it a late-model XT? The 1/10/1986 BIOS version "Added support for the 101-key Enhanced keyboard", in the words of IBM.
Click to expand...
So maybe it is a BIOS issue, thanks for the tip!

cr1901 said:
Some clones come with a keylock a la the AT, and sometimes (emphasis because it goes both ways apparently) the connection for the keylock needs to be shorted with a jumper to unlock the keyboard if you don't have a keylock. In this case, open circuit for the pins, which would happen if you didn't have a keylock, means keyboard is locked. Do you have the manual for the Turbo XT motherboard or can otherwise figure out if it has provisions for a keylock?
Click to expand...
The Turbo XT clone works correctly with the IBM PC Keyboard and the AT2XTKBD adapter, so it is not a keylock problem. It only fails with autoswitching keyboards.
 
More tests:
- In a second Turbo XT Clone, the Model M works correctly, but the Philips P2814 keyboard (autoswitchable) does not. The Philips works correctly when connected to the IBM 5160 XT.
- Another discovery: the IBM Model M2 from my PS/1 also is autoswitchable too and works both with the IBM 5160XT and the second Turbo XT Clone.
 
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