Discusses how Morse code isn't very clear without the third (usually) unseen element, the space.

Is there a (historical?) human-optimised (vs. say, ascii or something) binary (on vs. off) code for transmitting information?

After sleeping on it, I recall one code used by Vietnam-era POWs, based on a 5x5 grid reference, optimised for decoding/learning (alphabetical order) vs. optimised for use. But, I'm not sure that it didn't also use spaces.

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    This is not a history question by any length, as it stands now. – Rajib Dec 13 '14 at 9:21
  • Why not? What type of question is it? – user3082 Dec 13 '14 at 15:04
  • Computer science experts might know what you are talking about. Your requirement is for a particular type of code. The specifications make it the subject of computer science experts or mathematicians. Whether it existed in the past is immaterial. Else people can ask calculus questions here because after all it was invented in the past. – Rajib Dec 13 '14 at 15:20
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    The problem is your definition comes through a specification- not a readily understood term outside specialized circles. I could ask if a DCT based algorithm existed before 1995. That does not make it a history question. – Rajib Dec 13 '14 at 15:31
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    There's the smoke signal that the Vatican Council uses to communicate when they are voting. Black smoke means they haven't elected a new Pope yet, and white smoke means they have. I'd imagine a lot of other smoke signal systems can be thought of a binary communications as well, as the medium has many similarities to telegraph. – T.E.D. Dec 13 '14 at 22:17

http://en.wikipedia.org/wiki/Braille , in its various language formats, is a binary human-optimised code. http://en.wikipedia.org/wiki/Night_writing , Braille's precursor, also fits your description request. Both codes are fixed-length, and therefore do not suffer from the problem as quoted in the question.

  • Not to mention various smoke and visual signals used over centuries. – Michael Dec 14 '14 at 6:33

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