IBM XT Keyboard with Pseudo HHKB Mac Layout

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Hypersphere

13 Apr 2014, 19:03

Here is my IBM XT keyboard that I have remapped using KeyReMap4MacBook. It is connected to my Mac using a Hagstrom Electronics converter, and the keyboard is shared with a Linux box and Windows machine using Synergy. Thanks to Muirium for many of the remapping ideas!

I put a small Return key in place of the Backquote (`) key, and put the Backspace (back Delete) in place of the former Return key. This placement gives it a "pseudo HHKB" layout for Return and Backspace. "F" = Fn, replacing the former */PrintScreen; Fn is set to emulate HHKB functions, such as the cursor diamond and F-keys. Command replaced CapsLock, and Option replaces the KeyPad zero key. Arrow keys are toggled with KeyPad numbers using NumLock. Scroll Lock has been remapped as Power; I can actually shut down my Mac from the XT keyboard!
XTkeyright1a.jpg
XTkeyright1a.jpg (940.13 KiB) Viewed 1528 times
On the left side of the keyboard, F10 was remapped to left Option and left Alt to left Command. On the XT, Ctrl is already where it belongs, to the left of the "A" key.
XTkeyleft1a.jpg
XTkeyleft1a.jpg (886.13 KiB) Viewed 1528 times
Other touches included replacing the small shift keys with slightly larger ones and replacing the plain-surface F and J keys with ridged ones. IBM Replacement keys were from a 122-key IBM and a standard Model M; Option and Command keys were from Unicomp.
The keyboard was in reasonably good shape inside. The controller looked pristine and the back plate was fine; the front plate with the spring barrels had scattered focal pitting and could probably benefit from sanding and painting. The exposed edges of the foam layer sandwiched between the front and back plates was badly deteriorated into foam dust; I did not separate the plates. At same stage, it would be good to replace the foam layer.

Unlike Model M keyboards, the sticker on the rear of the XT case is small and lacking a build date; it showed the PN as 1801449. Inside the case there was a date handwritten in marker ink: 20/3/84, which presumably is March 20, 1984.

This keyboard is a joy to use. The buckling spring capacitive switches in the XT keyboard have a more precise feel and definitive sound than the buckling spring membrane switches in a Model M. Moreover, this machine is solid and heavy; weighing about 5.8 lbs (2.6 kg) and measuring roughly 7.8 x 18 in (19.8 x 45.7 cm), the XT keyboard could serve as a shutter panel for Dr. Morbius' house; one has the feeling that only monsters from the id could penetrate it.
Last edited by Hypersphere on 13 Apr 2014, 19:46, edited 1 time in total.

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fifted

13 Apr 2014, 19:22

Or the wizard of id...

Cool board! Love to see something from '84 getting the use it deserves.

The sunken foam gives it a very spaced-out look, like each key is an island...

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Hypersphere

13 Apr 2014, 19:36

Thanks! There is a certain poetic justice in using a 30-year old IBM XT keyboard with a Mac, considering that the first Mac was also produced 30 years ago, in 1984.

Regarding keys as islands, I would paraphrase John Donne and say that no key is an island entire of itself, every key is a piece of the board, a part of the main... :)

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Hypersphere

13 Apr 2014, 22:58

Update: I've made some revisions that I think improve the aesthetics and functionality somewhat. I remapped Backslash to Backquote and Delete to Backslash. Now the Backslash and Tilde (~) key is to the immediate right of Left Shift, and the Backslash (\) key is on the top row between = and Num Lock, where the original Delete was located. I substituted a 1.5x Backslash key from a Model M for the 1x Backslash key on the XT; this swap better fills in the empty space in this location. In addition, I put the original Return (Enter) key in place of the 1x Delete key; this also fills in a considerable amount of empty space. Now the only problem is having two adjacent keys with the Return (Enter) symbol. Users of this keyboard simply have to remember that the nearer 1x Enter key is the true Enter, whereas the farther and larger vertical Enter key is the back Delete (Backspace).

This seems fine. However, if anyone knows of a better vertical key for Delete (Backspace) that would fit in the original Return key space on the XT, please let me know. Note that the large keys on the XT have a centrally located mounting stem and no stabilizer stem. The only stabilized key is the super-long spacebar.

My KRM4MB settings and private.xml file are shown as images below for anyone who would like to reproduce these remappings.
Spoiler:
private.xml.png
private.xml.png (167.73 KiB) Viewed 1493 times
Spoiler:
KRM4MBsetting.png
KRM4MBsetting.png (91.27 KiB) Viewed 1493 times

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Hypersphere

23 Apr 2014, 00:11

After some experimenting, I've come up with a further revision that works extremely well for me. The most significant improvement was to put a 1.25x Backspace (back Delete) directly above the Return key, thus splitting the left and right bracket keys. This is possible, because the original right bracket key is 1.25x on the XT keyboard. Despite the 1x size of the Return key, it is located where I expect to find it and presents no problems.

Right side of keyboard, showing the black tan Backspace (back Delete) above the Green Return key. Light Blue = right Fn, Dark Blue = right Option (Alt); Red = right Control. Right Command is shown adjacent to the Spacebar. Among other things, Fn toggles back Delete to forward Delete and creates a cursor diamond from the [ / ; ' keys (as in the HHKB layout). NumLock toggles arrow and number keys in the NumPad, and Scroll Lock/Break = Power.
xt140422r.jpg
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Left side of keyboard. Red = Control; Dark Blue = Left Option (Alt); Light Blue = left Fn. Left Command is shown next to the Spacebar. Among other things, Fn toggles Escape to Backquote (`) and Fn+shift = Tilde (~).
xt140422l1.jpg
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This is a very easy modification to do, requiring only the purchase of a converter box, installation of free remapping software, and swapping some keycaps (e.g., from other IBM keyboards or Unicomp). I hope that this post might be useful for others who are thinking of using an IBM XT keyboard with a modern computer. I would also welcome suggestions on other ways to modify the XT keyboard.

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