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On Mar 18, 7:44�am, Klystron wrote:
� �I am trying to convert "words per minute" into "bits pe r second." Bits per second, in turn, is APPROXIMATELY equal to baud, a common measure of modem (or other means of data transmission) speed. I need to quantify one factor: How many letters are in a "word?" If we assume that there are 5 (five) letters to a word, my calculations look like this: It has been common convention in wireline telegraphy to count "one word" as having 5 characters followed by a space. The origin of that seems to be that it was most advantageous for humans to use/remember while using the Commercial Codes, a form of encipherment both to protect information and to reduce the number of words in a telegram. Bentley's Commercial Code seems to have been the most used with 17 editions, publishing Code Books for any business or government. As a result of those Commercial Codes, actual cryptographic codes also used 5 characters followed by a space, hence the term '5-letter groups' in referring to a "word." By the time of WWII starting, the cryptographic systems were more advanced and it was not possible to tell one 'word' from another but it was common practice to send encrypted text as 5-letter (or character) groups; the actual space in clear text was determined by the null or space substitute in poly- alphabetic rolling-key encryption codes. (reference: M-209 Code Converter used in the field in Europe by US forces) 73, Len AF6AY |
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