View Full Version : Understanding keyboards for IBM computers

June 19th, 2014, 10:06 PM
First off, thanks so much to everyone who helped me in my last thread.

So, I recently got an IBM clone for cheap at a swap meet. It didn't come with a keyboard, and at the time, I had no way to plug it in to any of my monitors or TVs. I got a video card that will let me see it on a TV, but I have a few questions about keyboard compatibility. The computer's case says it's an "Avantage XT turbo", so I would imagine that makes it an XT clone. I looked on Ebay to see what keyboards I could get for it, and I found this one that seems to come from the mid 90's (http://imgur.com/a/BhCQ6). It says on the box that it is an XT/AT keyboard, but plugging it in to the computer makes it spit out "K-B Error!" (Keyboard error?) on the screen after booting. Then, when DOS 2.11 loads, whenever I try to type anything in, there is no telling what it will display on screen (http://i.imgur.com/tAFglEh.jpg). None of the characters you see in that image were caused by my pressing the correct key. Is this because my keyboard is sending the keystrokes as AT, and my computer is reading them as XT? I can't seem to find any information about this keyboard to see whether or not it can actually switch between XT and AT. There's certainly no switch on the keyboard that lets it change mode. Does an AT/XT keyboard have a different meaning than just an AT or just an XT keyboard? Is there some sort of simple hardware modification that I need to do to set the mode?

Thanks again!

**Edit** Wong picture for keyboard input. It does display things on the screen, just not the right keystrokes.

June 19th, 2014, 10:34 PM
Do you see some sort of switch on the keyboard to switch from XT to AT? Usually underneath?

EDIT:Actually I just looked at your photos. The keyboard does not seem to support the PC/XT protocol, only AT and above.
I wonder why they wrote XT/AT on the box?

June 19th, 2014, 10:46 PM
Did it come with the PS/2 adapter?
Can you test it on a newer PC and see if it works?

June 19th, 2014, 10:53 PM
It doesn't come with the PS/2 adapter mentioned on the back of the box. The only thing that came in the box was the keyboard and it's plastic wrap. I've scoured the keyboard both internally and externally and the closest thing I found to a switch was a deceptively switch-like lump of plastic on the inside.

June 19th, 2014, 11:01 PM
Do you happen to have a 486 computer or something newer than a XT with the 5-pin DIN connector?
The keyboard has Windows keys, so it's probably a newer one that dropped PC/XT support.

If I'm reading the box right, the keyboard should have a PS/2 connector and the adapter is actually to adapt it to a 5-PIN DIN. It says to install to a 5-pin DIN, you will need a 6 to 5 adapter. This must be wrong if the keyboard cable ends in a 5-pin DIN. If that error is printed on the box, the XT part is probably an error too.

Does the model number match up to what's supposed to be in the box? Maybe the box is not correct for the keyboard.

June 19th, 2014, 11:06 PM
I remember back then a lot of keyboard boxes having written that XT/AT thing on them. In my mind it was registered as using the same box for multiple products, so keep it in mind as a possibility.
Certainly there is no XT/AT special keyboard, just those with a switch, so if the keyboard works on an AT machine and doesn't have any switch then this is probably the case...

June 19th, 2014, 11:10 PM
If it has Windows 95 keys, you can be pretty certain it does not support the XT protocol.

If buying a generic one, preferably stick to models that have an AT or XT switch underneath, have been tested by the seller on an XT, or at least have an absence of num/caps/scroll lock and F1-F10 on the left.

Example of a proper XT/AT keyboard: http://www.ebay.com/itm/Vintage-Mitsumi-KPQ-E99YC-Easy-Data-Keyboard-W-AT-XT-Switch-/331237715401?pt=US_Vintage_Computing_Parts_Accesso ries&hash=item4d1f4e6dc9 (bad example because the switch is tiny - but it is there underneath)
Example of XT only: http://www.ebay.com/itm/VTG-IBM-PC-XT-5150-5160-CLicky-84-Key-Keyboard-/111383199652?pt=US_Vintage_Computing_Parts_Accesso ries&hash=item19eef4bfa4

There is also auto sense, my Commodore keyboards do this, but you can't be sure until you plug them in - so when ordering from ebay I don't rely on auto-sense being there.

Edit: also I'm not endorsing those listings, just examples, preferably get something tested or with a DOA guarantee.
Edit: switches are usually easily accessible and marked "A" and "X" or "PC" and "AT" or "XT" and "AT". Almost always on the back, and aren't hard to find if they're there.

June 20th, 2014, 12:03 AM
A possible option to use AT-class keyboards is the use of the AT2XT keyboard converter. See [here (http://www.vintage-computer.com/vcforum/showthread.php?26426-AT2XT-keyboard-converter)].

June 22nd, 2014, 09:16 AM