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  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:
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.
Get a genuine IBM/ Lexmark keyboard, part no. 60G3571 or KB-571,
sometimes referred to as the Professional 101-key keyboard (see ). These keyboards used to be widely available in
stores, but by 1996 they'd become quite scarce because Lexmark stopped
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
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  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.
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
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.
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
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.
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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