Morse code
A method of encoding text using dots and dashes.
Morse code turns letters and numbers into patterns of two signal lengths—dots and dashes, also called dits and dahs. It’s named after Samuel Morse, though he was just one of the people who worked on it. The code gets sent by switching a carrier—like electric current, radio waves, light, or sound—on and off. People who learn it can understand it directly through their ears or eyes.
The system’s history starts with early 19th-century European experiments in electrical signaling, using static electricity or Voltaic piles to create electrochemical or electromagnetic effects. After Hans Christian Ørsted discovered electromagnetism in 1820 and William Sturgeon invented the electromagnet in 1824, electromagnetic telegraphy took off in both Europe and America. Early setups often used a single needle: a left deflection meant a dit, a right one a dah. The needle clicked on each move, and by giving the two clicks different sounds (one ivory stop, one metal), operators could hear the signal as well as see it—leading to the Double Plate Sounder System. In Britain, William Cooke and Charles Wheatstone patented an electromagnetic telegraph in June 1837 and demonstrated it on the London and Birmingham Railway, making it the first commercial telegraph. Carl Friedrich Gauss and Wilhelm Eduard Weber (1833) and Carl August von Steinheil (1837) also used codes with varying word lengths. By 1841, Cooke and Wheatstone had a telegraph that printed letters from a wheel of typefaces.
Samuel Morse, an American artist, worked with physicist Joseph Henry and engineer Alfred Vail to develop an electrical telegraph. Because its signals were simply on or off, they needed a way to transmit language using only pulses and silences. Around 1837, Morse created an early version of what became modern International Morse code. His original telegraph receiver used clockwork to move a paper tape; an electromagnet pushed a stylus onto the tape when current flowed, leaving an indentation, and a spring pulled it back when the current stopped. Morse first planned to send only numbers, with a codebook to translate each number into a word, but Vail expanded the code in 1840 to include letters and special characters. Vail figured out English letter frequencies by counting the movable type in a printer’s type cases.
The code itself has no uppercase or lowercase.
- Named after
- Samuel Morse
- Basic units
- dit and dah
- Dit duration ratio
- dah is three times the duration of a dit
- Letter space
- three dits
- Word space
- seven dits
- Letters encoded
- 26 basic Latin letters A to Z, one accented Latin letter É, Indo-Arabic numerals 0 to 9, and some punctuation and prosigns
- No case distinction
- true
Lore & Background
Morse code was developed from an early forerunner created by Samuel Morse around 1837, which was later expanded by Alfred Vail in 1840 to include letters and special characters. Vail estimated English letter frequency by counting movable type in a local newspaper's type cases, assigning the shortest sequences to the most common letters. The original Morse landline code, also called American Morse code or Railroad Morse, was first used in 1844. Friedrich Gerke refined the code in 1848, producing the 'Hamburg alphabet,' which eliminated different length dashes and inter-element spaces, leaving only the dot and dash. Gerke's code was adopted in Germany and Austria in 1851, and most of its alphabetic part was copied into the International Morse code adopted in 1865. The International Morse code added a code point for J, changed codes for X, Y, and Z, and completely revised the digit codes, leaving only four codes identical to the original Morse code.
Reader's Guide
Morse code's significance lies in its role as a practical method for transmitting natural language using only electrical pulses and silence. It was designed so that the duration of each symbol is approximately inverse to the frequency of the character in English text, increasing transmission efficiency. The code is sent at the highest rate the receiver can decode, as elements are specified by proportion rather than fixed duration. Morse code can be memorized and sent in forms perceptible to human senses, such as sound waves or visible light. Later training found that people become more proficient when taught to perceive each code as a whole 'word' rather than a sequence of separate dots and dashes. Operators began vocalizing a dot as 'dit' and a dash as 'dah' to reflect the sounds of radiotelegraph receivers. Morse code was sometimes facetiously known as 'iddy-umpty.' For languages using more than the 26 Latin letters, Morse alphabets have been developed largely by transliteration of existing codes.
Did You Know?
- The most common letter in English, E, has the shortest code – a single dit.
- The duration of a dah is three times the duration of a dit.
- Words are separated by a space equal to seven dits.
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