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Morse Code

Morse code is a method for transmitting information, using standardized sequences of short and long marks or pulses. These are known as "dots" and "dashes" for the letters, numerals and special characters of a message.

Samuel Morse and Alfred Vail developed an electric telegraph, which used electrical currents to control an electromagnet that was located at the receiving end of the transmission wire in the year 1830. The technological limits of the time made it impossible to print individual characters in a readable form, so the inventors had to devise an alternate method of communication. Beginning in 1837, William Cooke and Charles Wheatstone operated electric telegraphs in England, which also controlled electromagnets in the receivers, however, in their systems needle pointers were rotated in order to indicate the characters being sent. In contrast, Morse and Vail's initial telegraph system, which first went into operation in 1844, marked a paper tape — when an electrical current was transmitted, the receiver's electromagnet rotated an armature, so that it began to scratch a moving tape, and when the current was removed the receiver retracted the armature, so that portion of the tape was left unmarked.


--. .-. . -. --.. . -. -.. . … ..-. --- .-. -- .- .-.. . -.


The code was also extensively used for early radio communication beginning in the 1890s although it was created for Samuel Morse's electric telegraph in the mid-1830s. However, with the development of more advanced communications technologies, the widespread use of Morse code is now largely obsolete, apart from emergency use and other specialized purposes, including navigational radio beacons, and by CW amateur radio operators. Morse code is the only digital modulation mode designed to be easily read by humans without a computer, making it appropriate for sending automated digital data in voice channels, as well as making it ideal for emergency signaling, such as by way of improvised energy sources that can be easily "keyed" such as by supplying and removing electric power. Morse code can be transmitted in a number of ways:

  • originally as electrical pulses along a telegraph wire,
  • but also as an audio tone,
  • as a radio signal with short and long pulses or tones,
  • or as a mechanical or visual signal (e.g. a flashing light) using devices like an Aldis lamp or a heliograph.

Because Morse code is transmitted using just two states — on and off — it was an early form of a digital code. International Morse code is composed of six elements:

  • short mark, dot or 'dit' (·)
  • longer mark, dash or 'dah' (-)
  • intra-character gap between signs, a break for one dit
  • short gap between letters, a break of three dits
  • medium gap between words, a break of seven dits
  • long gap between sentences

Telegraph companies charged based on the length of the message sent. Elaborate commercial codes were developed that encoded common phrases in five-letter groups that were sent as single words. In computer networking terminology one would say the commercial code is layered on top of Morse code, which in turn is layered on top of binary code, which in turn is layered on top of a physical telegraph wire. Still in use in Amateur Radio are the Q code and Z code. They were and are used by the operators themselves for service information like link quality, frequency changes, and telegram numbering.

Recently a few widely publicized speed contests have been held between expert Morse code operators and expert cellphone SMS text messaging users. Morse code has consistently won the contests, leading to speculation that cellphone manufacturers may eventually build a Morse code interface into cellphones. The interface would automatically translate the Morse code input into text so that it could be sent to any SMS capable cellphone so therefore the receiver of the message need not know Morse code to read it.

Further information and links:

Morse Code
Java Morse Code Translator
Samuel F. B. Morse