IBM 1620 invalid character symbol

Ken Whistler via Unicode unicode at
Wed Sep 27 12:42:54 CDT 2017


On 9/27/2017 10:02 AM, Asmus Freytag via Unicode wrote:
> In that context it's worth remembering that there while you could say 
> for most typewriters that "the typewriter is the font", there were 
> noted exceptions. The IBM Selectric, for example, had exchangeable 
> type balls which allowed both a font and / or encoding change. 
> (Encoding understood here as association of character to key).
> That technology was then only two years in the future.

And in some sense, not even... ;-)

By the 1950's (and probably earlier), enterprising linguists and other 
special users were conspiring with skilled typewriter repair experts to 
customize their manual typewriter keyboards and key strikers with custom 
fonts. I have an example sitting in my office -- an old Olympia manual 
typewriter with custom-cast type replacing the standard punches on some 
of the key strikers, and with custom engraved key caps added to the 
keyboard, to add schwa, eng, open-o, etc. to the typewriter. It also has 
the bottom dot of the colon *filed off* to create a middle dot key. 
Typing an actual colon on that machine requires an "input method" 
consisting of 3 key presses: {period, backspace, middledot} A couple of 
the keys that have raised accents on them were modified so as disable 
the platen advance, thereby becoming permanent "dead keys" -- 
effectively emulating the encoding of combining marks. There are 
probably thousands of such customized manual typewriters still sitting 
around, over and beyond the various standard manufactured models.

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