APL Keyboard

A question posed in comp.lang.apl:
Where can I get an APL keyboard for an IBM PC?
You can, of course, get APL stickers that can be applied to just about any keyboard. A keyboard reference card is another alternative. Both of these may be available from your APL vendor. (See [1] below.) But stickers are messy and eventually wear off, and a reference card never seems to be around (or visible on your desk) when you need it. If you're a serious APLer, you might want to treat yourself to a serious APL keyboard:
  Stop Press!
Unicomp, the keyboard manufacturer that took over the business from IBM/Lexmark, has APL keyboards available directly! You don't have to assemble one from parts as described below. To order one of these, call them at 800-777-4886 and ask for keyboard number UNZ1416. If you're not using IBM's APL2, you may still want to assemble your own keyboard as described below. Some of the keys are not labeled correctly for other APL systems, and you may want to retain the original caps for those keys.
1. Get a genuine IBM/ Lexmark keyboard, part no. 60G3571 or KB-571, sometimes referred to as the Professional 101-key keyboard (see [2]). These keyboards used to be widely available in stores, but by 1996 they'd become quite scarce because Lexmark stopped making them. Lexmark eventually sold the keyboard business to Unicomp, which as of March 2000 still has a limited number of these keyboards available for the bargain price of $49 (half what I paid for mine!). You can order one via the Web or call Unicomp at 800-777-4886 and ask for part number 42H1292. (However, beware that these keyboards may have integral cap & stem keys which can't use the IBM APL keycaps. See the Caution below.)
If you're a real cheapskate you may be able to find one at a local tag sale, or you can try that great mother of all virtual tag sales, eBay, and their Ye Olde IBM Keyboards specialty shop. I believe the KB-571 is sometimes referred to as the "Model M" or "buckling spring" keyboard. Another source is given in [3] below.
Note: Be forewarned that "quiet" is not a term I would use to describe this keyboard; "machine-gun" might be closer. Unicomp offers some quieter keyboards, but I haven't seen any of them so I can't comment on the typing quality and I don't know if the keycaps are removable. If you buy one of them, please let me know what you think of it.
2. Once you have the keyboard, order a set of APL2 keycaps from IBM. Call 800-879-2755 and order part number SX80-0270-00 for about $46. If you live in a non-English speaking country, you may want to order also one of the "supplements" for your national language characters. The German supplement is part number SX23-0452; the French supplement is SX23-0453; and the Italian supplement is SX23-0454.
Caution: The keys used in these keyboards come in two varieties: separate cap & stem, and integral cap & stem. To tell what type you have, grab the F1 key by the front and back, squeeze, and pull upwards. If the cap comes off to reveal a nude button beneath, you have a separate cap & stem keyboard, and the IBM keycaps above are just what you need. If, however, the key pulls out with a stem like a molar root and there's just a black tube with a spring left in the keyboard, you have an integral cap & stem type. Unicomp probably has the APL keycaps you need; call them for assistance.

Although the combination isn't cheap, it's probably less than custom-made keycaps, and the result is a great APL keyboard. I like it even better than the original IBM PC keyboard I was planning on being buried with.
The layout of APL symbols on the resulting keyboard is appropriate for IBM's APL2 and is mostly correct for APL*PLUS and Dyalog APL. (The keycaps for [, ], and \ are wrong, and the layout is for the traditional APL keyboard rather than the newer unified layouts, so the + and - keys are mislabeled.) Sharp APL uses a rather different keyboard layout, so the keycaps probably aren't useful with that system.
The APL2 keycaps were made before the diamond symbol was added to APL2, so that key isn't properly labeled. If you really want the diamond, you can order the Italian supplement (part SX23-0454) at a cost of about $12. Or you can just put a sticker on that key.
[1] APL2 keyboard stickers are available from IBM by calling 800-879-2755 and ordering part number SC33-0604. They cost about $13 for a set of two.
[2] If you already have an IBM 101-key keyboard, you may have what you need. Grab the F1 key by the front and back, squeeze, and pull upwards. The keycap should come off, revealing an unlabeled keybutton beneath. If the keycap measures about 16.5 mm inside width at the base and has tabs on the sides, your keyboard can probably take the APL keycaps.
[3] One source for used and refurbished keyboards is Celtech Services, located in Georgia. I've seen reports that they even sell ready-made APL keyboards. Call (404) 263-6060 and ask for Mike Resnick or Chris.

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