Prosigns for Morse code

Morse code prosigns or procedural signals are unique, special, dot/dash sequence symbols e.g. (▄▄▄▄▄▄▄▄▄▄▄▄▄▄) that do not represent written or printed human-language alpha-numeric or punctuation textual characters. Instead, prosigns are specialized (normally unwritten) stand-alone dot/dash sequence symbols, that have specific non-language functions, such as: indicating changes of transmission status, and indicating (or initiating) textual white space formatting. Although preceding teleprinter (teletypewriter) and computer character set control characters by many decades, these traditional Morse prosigns play a role similar to the role played by the modern (normally unprinted) control characters of teleprinter and computer character set codes such as the: Baudot, Murray, ITA2, ASCII, Unicode and EBCDIC codes. Morse code prosign symbols have been used by telegraphers (American English), or telegraphists (British English), since the 1860s, predating modern character set code control characters by almost one hundred years.

Morse code symbols that represented literal alphabetic characters, numerals and some punctuation marks were originally created by the inventors of Morse code Samuel Morse and Alfred Vail. At first these basic alpha-numeric and punctuation Morse code symbols were transmitted by simple electrical switching mechanisms and upon reception were transcribed by simple machinery that made short and long marks on long paper tapes. Such methods were sufficient for experimental and proof of concept work in the early development of telegraphy. Later telegraph operators learned to listen to telegraph signals by ear and receive Morse code mentally as it was sent in real time. At first mentally received Morse information was manually recorded by operators using pencil on paper in real time as the signals arrived. Later higher speed operations on reception were obtained by operators skilled in the use of the typewriter. Subsequently Morse code sending speeds increased as more efficient hand-operated telegraph keys such as the Vibroplex semi-automatic or bug keys were developed. And so, over a short period the average speed of Morse code telegraph transmission increased by at least 50 times from less than a single word per minute to upwards of 40-60 words per minute. Today amateur radio operators who still use Morse code either copy Morse manually by pencil onto paper, or type the text into electronic document files using text editor applications as they receive Morse signals by ear in real time. Some modern day operators copy Morse at speeds up to and beyond 70 words per minute. Recently with the advent of microprocessors and inexpensive personal computers special Morse decoding computer applications (Morse code readers) have been developed which can decode and record accurately sent Morse code automatically at speeds approaching 100 words per minute.

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