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Morse code
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==== Digital storage ==== Morse code is transmitted using just two states (on and off). Morse code may be represented as a binary code, and that is what telegraph operators do when transmitting messages. Working from the above ITU definition and further defining a [[bit]] as a dot time, a Morse code sequence may be crudely represented a combination of the following five bit-strings: # short mark, dot or ''dit'' ({{morse|dot}}): '1'b # longer mark, dash or ''dah'' ({{morse|dash}}): '111'b # intra-character gap (between the ''dits'' and ''dahs'' within a character): 0 # short gap (between letters): '000'b # medium gap (between words): '0000000'b The marks and gaps alternate: ''Dits'' and ''dahs'' are always separated by one of the gaps, and that the gaps are always separated by a ''dit'' or a ''dah''. A more efficient binary encoding uses only two-bits for each ''dit'' or ''dah'' element, with the 1 ''dit''-length pause that must follow after each automatically included for every 2 bit code. One possible coding is by number value for the length of signal tone sent one could use '01'b for a ''dit'' and the automatic single-dit pause after it, and '11'b for a ''dah'' and the automatic single-''dit'' following pause, and '00'b for the ''extra'' pause between letters (in effect, an end-of-letter mark). That leaves the code '10'b available for some other purpose, such as an escape character, or to more compactly represent the ''extra'' space between words (an end-of-word mark) instead of '00 00 00'b (only 6 ''dit'' lengths, since the 7th is automatically inserted as part of the prior ''dit'' or ''dah''). Although the ''dit'' and inter-letter pauses work out to be the same, for any letter containing a ''dah'', the two-bit encoding uses digital memory more compactly than the direct-conversion bit strings mentioned above. Including the letter-separating spaces, all International Morse letter codes pack into 12 bits or less (5 symbols), and most fit into 10 bits or less (4 symbols); most of the [[prosigns for Morse code|procedural signs]] fit into 14 bits, with a few only needing 12 bits (5 symbols); and all digits require exactly 12 bits. For example, Morse '''{{sc|g}}''' ({{morse|dash|dash|dot}} + 2 ''extra'' empty dits for "end of letter") would binary-encode as '11'b, '11'b, '01'b, '00'b; when packed it is '1111 0100'b = 'F4'x, which stores into only one [[byte]] (two [[nibble]]s) (as does every three-element code). The bit encoding for the longer method mentioned earlier the same letter would encode as '1110'b, '1110'b, '1000'b = '1110 1110 1000'b = 'EE8'x, or one-and-a-half bytes (three nibbles). The space saving allows small devices, like portable memory keyers, to have more and longer International Morse code sequences in small, conventional device-driver [[microprocessor]]s' [[random access memory|RAM]] chips.
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