Over in my question about input devices with character sets suited to Algol 60, I mentioned using an ASR-33 / KSR-33 teletype with the subscript-10 character ₁₀.

I have subsequently been unable to find details of what typewheels were available on teletypes. This parts manual lists several typewheels, giving part numbers and a two-letter code for each, but I can find no description of their character repertoires.

(If you look at the parts list, just search for 'typewheel')

What were the various typewheel configurations available for model 33 teletypes? The answer I'm looking for will say what characters were available, and ideally what their codepoints were. An easy way to write this up might be 'differences from ASCII', of whatever flavor of ASCiI you prefer to use as base.

3 Answers 3


[No time for a real answer (got to push my narrowboat from Wolverhampton to B'ham), but ...]

This page (which is a marvellous collection of TTY manuals) does have at least two charts (7171WD, 7172WD) showing their encoding/population side by side (caution, strange PDF settings).

  • In the 7171WD document, it mentions the "original customer" for each, which suggests they'd make typewheels to customer specification. Sep 9, 2020 at 22:13
  • 1
    In 7172WD, the "MS" (184950) typewheel for Westrex has both '10' and '11' symbols, presumably for sterling pence. Though I find it peculiar that that was considered useful, given there were not similar symbols 12,13,...,19 for the shillings field. (Every character-code answer leads to 2 more questions!) Though tickling at the corner of my brain is the thought that I saw typography where the pence after the solidus was in smaller digits than the shillings before it. Sep 9, 2020 at 22:20
  • @another-dave Maybe compare the second picture in this keyboard answer that model uses as well two digits for shilling but only 'one' for pence. Going that way saves a whole stage (digit). I guess that was quite common. It also fits the inertia people using ancient measurements show :))
    – Raffzahn
    Sep 10, 2020 at 8:31

At Waterloo, the old Teletypes were gradually replaced by IBM Selectrics. Those used the "Script" and "APL" character sets, among others...

IIRC, the older Teletypes also had the "APL" set - as we used APL a lot in those days (ca. 1975).

  • University of Waterloo; Waterloo Station; or Waterloo, site of Napoleon's defeat? ;-) Sep 9, 2020 at 22:02

I'm not sure of the ASR-33, but I did find a "type book" for the Diablo 630, which was available in a teleprinter terminal configuration (as well as a pure printer). The selection there might be representative. Look in the last few pages for a complete set of character maps, including both character codes and spoke positions.

And yes, there is at least one character set specialised for APL.

  • 1
    The Diablo 630 was much later (1980 vs. 1963) and a world apart. Except in broad-based functional description (type stuff, print stuff) it was an entirely different (and way more advanced) device compared to the TTY 33. Sep 10, 2020 at 14:42
  • Ar DEC Reading in the latter half of the 1970s, the doc team used some Diablo model for preparing camera-ready copy. You don't do that on a model 33 teletype. Sep 10, 2020 at 14:52

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