Data communications over telegraph circuits 1942

The common meaning of "Baudot code" today the American variation of ITA2 (International Teletype Alphabet 2) standardized by the CCITT in the 1930's, and is not the original code developed by Johann Gauss and Wilhelm Weber (used by Emile Baudot in 1874), and equally is not the code developed by Donald Murray in 1901.

Note that neither Baudot or Murray worked with a stop-start code, though Murray's code was adapted to stop-start mechanisms when that became popular (1920's, mostly the work of Frederick George Creed, though it was invented in 1907 by Charles Krumm.

Compatibility between Bell 103 and TTY modems was not the point, the question was whether a modern "plain 8 bit modem" can handle 5 level codes. It can.

Many, though I don't know if it is yet most, TDD modems will can switch between Bell 103 (or v.21) and the old TDD standard.

However, "more recent modems" are *not* Bell 103 modems, even if they emulate them. I don't know offhand which might work below 300 bps and which might not; but any modem that buffers the RS-232 i-o will have a problem with random speeds. I'm guessing, but it is likely that a majority of modern modems cannot disengage input buffering, and therefore will not work at odd rates. Such buffering is a requirement for all modems with error correction, hence it is unlikely that any common modem which works at 2400 bps or above lacks i-o that is buffered.

It easily could have, because typical modems used to extend a terminal did *not* buffer the i-o. Usually that would have been a Bell 201 or Bell 202 modem.

Murray's code was designed to reduce the wear and tear on hardware, while Morse was designed to reduce wear and tear on the operator. Both result in code that is easy for that purpose.

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