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Morse code is a SIGNALING code first devised by Samuel F.B. MORSE in 1838 for use with his
electromagnetic TELEGRAPH. The code used two basic symbols or signaling elements: the
"dot," a short-duration electric current, which gave a quick deflection of the armature of Morse's
receiver and so caused a dot to be printed on the strip of paper moving beneath the ink pen
carried by the armature; and the "dash," a longer-duration signal that caused a dash to be
printed. Using this code, the various alphanumeric characters that compose a message (letters
and numerals) could be represented by groups of these two signal elements. In the International
Morse code, for example, one dot followed by one dash (.-) symbolizes the letter A; the number
seven appears as "dash dash dot dot dot" (--...). The dot-and-dash elements are separated by an
interval that has the duration of one dot; the dash has a duration equal to three dots. The space
between characters, whether letters or numbers, is equal to three dot units; the separation
between words is six units. Morse's code rapidly gained acceptance and evolved into several
forms -- Early Morse, American Morse, and International Morse. In its international form it is still in
use.
Although Morse devised his code for use with a printing telegraph, he and his colleague Alfred
Vail soon realized that messages could easily be read from the sound of the clicking armature.
When the printer was replaced by a simple buzzer, the operator could read the message from the
sequence of dots and dashes. Radio telegraphy was introduced in 1897, and Morse code was
again employed; in early use the radio signal would cause a sensitive relay to operate the local
printer or buzzer circuit. Similarly, Morse code was applied to the left and right beats of the
needle of the submarine telegraph and the light flashes produced by a signaling lamp used
between ships at sea. Morse's work dominated signal coding practice until well into the 20th
century.
[Eric Eastwood]
Bibliography:
Carron, Morse Code: The Essential Language (1986).
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