Bingo! Yes, there is. That's the other major change. There have been, I think, three major versions of ASCII. (Although ASCII seems to be a very clear-cut standard, the history becomes very intricate if you consider how ECMA, the US military, and possibly other standards bodies got involved. Also, I think the character code itself, and the devices that implemented it, influenced each other. So I don't know all the details.) First version - 1963 (?) - This only had uppercase; the control characters had slightly different names (which I don't have here -- sorry!) and code 176 octal was assigned to Escape. That's the reason why Hazeltine terminals have so much trouble with tildes, by the way. Second version - 1968 (?) - The one I mentioned. The same as ours except for the underline being a left arrow and the caret being an upward-pointing arrow. I think the control characters had their modern names Third version - when? - This is the version I grew up with and consider standard. It's the one found in zillions of ASCII charts. The standard hides some interesting details, though: - You are allowed to use some characters as accents by overstriking. They are ' ` ~ ^ " and (I think) , as a cedilla. - There are a couple of other deliberate ambiguities. The tilde can be an overline and ^ can be another representation for the PL/I-style logical not. (These ambiguities could be in another version -- I hope I'm not getting confused here.) Actually, I lied. There is a fourth version (it's an ISO standard or some- thing). And there are international variants too. But since the fourth verrsion is basically the same as the third version except for the names of control characters (all the separators are now numbered), I don't really consider it any different than the previous versions. -- Derek

Philip.Belben(a)PowerTech.co.uk wrote about the ASCII code that was originally a leftward-pointing arrow, but was later redefined as underscore: Um, no. ASCII doesn't define any shift-$ character. In fact, ASCII doesn't define any shift characters at all. It makes no association between characters and keystrokes. All it defines is the codes for the characters, and the functions of some of the control characters. Note that even in the case of control characters, it does NOT define them as being generated by a control key together with some other key. So, for instance, there is no proper ASCII character designated "Control-C". This style of usage is an artifact of bit-paired keyboards, as was discussed here last week. ASCII originally did not have an underscore character. Since the 1968 revision, it has an underscore but no leftward-pointing arrow. In any case, the Commodore PET did not use ASCII, although it used an extended character set that was derived from ASCII. So perhaps you are thinking of one of the Commodore line-drawing characters.

Philip.Belben(a)PowerTech.co.uk said... | |PET has a left arrow for that code as well. Sensible, since underscore is |available elswhere in the character set (shift-$ IIRC) but I never knew it |used to be standard ASCII. What other changes have there been? Is there |any precedent for PET using up-arrow instead of circumflex? Sems like that was standard on teletypes...