Morse code
Encyclopedia
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. The International Morse Code encodes the Roman alphabet
, the Arabic numerals
and a small set of punctuation and procedural signals as standardized sequences of short and long signals called "dots" and "dashes" respectively, or "dits" and "dahs". Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages.
Each character (letter or numeral) is represented by a unique sequence of dots and dashes. The duration of a dash is three times the duration of a dot. Each dot or dash is followed by a short silence, equal to the dot duration. The dot duration is the basic unit of time measurement in code transmission.
Morse code speed is measured in words per minute
(wpm). Characters have differing lengths because they contain differing numbers of dots and dashes. Consequently words also have different lengths in terms of dot duration, even when they contain the same number of characters. For this reason licencing bodies, such as the Federal Communications Commission (FCC) in the US, choose a standard word to measure operator transmission speed. "PARIS" and "CODEX" are two such standard words.
One important feature of Morse code is coding efficiency. The length of each character in Morse is approximately inversely proportional to its frequency of occurrence in English. Thus, the most common letter in English, the letter "E," has the shortest code, a single dot.
A related but different code was originally created for Samuel F. B. Morse's electric telegraph
by Alfred Vail in the early 1840s. This code was the forerunner on which modern International Morse code is based. In the 1890s it began to be extensively used for early radio
communication before it was possible to transmit voice. In the late nineteenth and early twentieth century, most high-speed international communication used Morse code on telegraph lines, undersea cables and radio circuits.
Morse code is most popular among amateur radio operator
s although it is no longer required for licensing in most countries, including the US. Pilots
and air traffic controllers are usually familiar with Morse code and require a basic understanding.
Aeronautical navigational aid
s, such as VORs
and NDBs
, constantly identify in Morse code. An advantage of Morse code for transmitting over radio waves is that it is able to be received over poor signal conditions that would make voice communications impossible.
Because it can be read by humans without a decoding device, Morse is sometimes a useful alternative
to synthesized speech for sending automated digital data to skilled listeners on voice channels.
Many amateur radio repeater
s, for example, identify with Morse even though they are used for voice
communications.
For emergency signals, Morse code can be sent by way of improvised sources that can be easily "keyed" on and off, making it one of the simplest and most versatile methods of telecommunication
.
Beginning in 1836, the American artist Samuel F. B. Morse
, the American physicist
Joseph Henry
, and Alfred Vail developed an electrical telegraph
system. This system sent pulses of electric current
along wires which controlled an electromagnet
that was located at the receiving end of the telegraph system.
In 1837, William Cooke
and Charles Wheatstone
in England
began using an electrical telegraph that also used electromagnets in its receivers. However, in contrast with any system of making sounds of clicks, their system used pointing needles that rotated above alphabetical charts to indicate the letters that were being sent. Cooke and Wheatstone in 1841 built a telegraph that printed the letters from a wheel of typefaces struck by a hammer. This machine was based on their 1840 telegraph and worked well; however, they failed to find customers for this system and only two examples were ever built.
On the other hand, the three Americans' system for telegraphy
, which was first used in about 1844, was designed to make indentations on a paper tape when electric currents were received. Morse's original telegraph receiver used a mechanical clockwork to move a paper tape. When an electrical current was received, an electromagnet engaged an armature that pushed a stylus onto the moving paper tape, making an indentation on the tape. When the current was interrupted, the electromagnet retracted the stylus, and that portion of the moving tape remained unmarked.
The Morse code was developed so that operators could translate the indentations marked on the paper tape into text messages. In his earliest code, Morse had planned to only transmit numerals, and use a dictionary to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail to include letters and special characters, so it could be used more generally. Vail determined the frequency of use of letters in the English language
by counting the movable type he found in the type-cases of a local newspaper in Morristown
. The shorter marks were called "dots", and the longer ones "dashes", and the letters most commonly used were assigned the shorter sequences of dots and dashes.
In the original Morse telegraphs, the receiver's armature made a clicking noise as it moved in and out of position to mark the paper tape. The telegraph operators soon learned that they could translate the clicks directly into dots and dashes, and write these down by hand, thus making it unnecessary to use a paper tape. When Morse code was adapted to radio communication, the dots and dashes were sent as short and long pulses. It was later found that people became more proficient at receiving Morse code when it is taught as a language that is heard, instead of one read from a page.
To reflect the sounds of Morse code receivers, the operators began to vocalise a dot as "dit", and a dash as "dah". Dots which are not the final element of a character became vocalised as "di". For example, the letter "c" was then vocalised as "dah-di-dah-dit".
In aviation, Morse code in radio systems started to be used on a regular basis in the 1920s. Although previous transmitters were bulky and the spark gap
system of transmission was difficult to use, there had been some earlier attempts. In 1910 the U.S. Navy experimented with sending Morse from an airplane. That same year a radio on the Airship America
had been instrumental in coordinating the rescue of its crew. However, there was no aeronautical radio in use during World War I
, and in the 1920s there was no radio system used by such important flights as that of Charles Lindbergh
from New York
to Paris
in 1927. Once he and the Spirit of St. Louis
were off the ground, Lindbergh was truly alone and incommunicado. On the other hand, when the first airplane flight was made from California to Australia in the 1930s on the Southern Cross (airplane)
, one of its four crewmen was its radio operator who communicated with ground stations via radio telegraph
.
Beginning in the 1930s, both civilian and military pilots were required to be able to use Morse Code, both for use with early communications systems and identification of navigational beacons which transmitted continuous two- or three-letter identifiers in Morse code. Aeronautical chart
s show the identifier of each navigational aid next to its location on the map.
Radio telegraphy using Morse code was vital during World War II
, especially in carrying messages between the warship
s and the naval base
s of the Royal Navy
, the Kriegsmarine
, the Imperial Japanese Navy
, the Royal Canadian Navy
, the Royal Australian Navy
, the U.S. Navy, and the U.S. Coast Guard. Long-range ship-to-ship communications was by radio telegraphy, using encrypted messages, because the voice radio systems on ships then were quite limited in both their range, and their security. Radio telegraphy was also extensively used by warplanes, especially by long-range patrol plane
s that were sent out by these navies to scout for enemy warships, cargo ships, and troop ships.
In addition, rapidly moving armies in the field could not have fought effectively without radio telegraphy, because they moved more rapidly than telegraph and telephone lines could be erected. This was seen especially in the blitzkrieg
offensives of the Nazi German Wehrmacht
in Poland
, Belgium
, France
(in 1940), the Soviet Union
, and in North Africa
; by the British Army
in North Africa
, Italy
, and the Netherlands
; and by the U.S. Army in France and Belgium (in 1944), and in southern Germany in 1945.
Morse code was used as an international standard for maritime communication until 1999, when it was replaced by the Global Maritime Distress Safety System
. When the French Navy
ceased using Morse code on January 31, 1997, the final message transmitted was "Calling all. This is our last cry before our eternal silence."
The United States Coast Guard
has ceased all use of Morse code on the radio, and no longer monitors any radio frequencies for Morse code transmissions, including the international CW medium frequency (MF) distress frequency of 500 kHz.
in 1848 and initially used for telegraphy between Hamburg
and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numeral
s resulting in substantially the modern form of the code. After some minor changes, International Morse Code was standardized at the International Telegraphy Congress in 1865 in Paris, and later International Morse Code made the standard by the International Telecommunication Union
(ITU). Morse's original code specification, largely limited to use in the United States and Canada, became known as American Morse code
or railroad code. American Morse code is now seldom used except in historical re-enactments.
, instrument pilots use radio navigation
aids. To ensure that the stations they are using are serviceable, they all emit a short set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, the VOR
based at Manchester Airport in England is abbreviated as "MCT", and MCT in Morse code is transmitted on its radio frequency. In some countries, if a VOR station begins malfunctioning it broadcasts "TST" (for "TEST"), which tells pilots
and navigator
s that the station is unreliable. In Canada, the ident is removed entirely to signify the navigation aid is not to be used.
International Morse code today is most popular among amateur radio
operators, where it is used as the pattern to key a transmitter on and off in the radio communications mode commonly referred to as "continuous wave
" or "CW". Other keying methods are available in radio telegraphy, such as frequency shift keying.
The original amateur radio operators used Morse code exclusively, since voice-capable radio transmitters did not become commonly available until around 1920. Until 2003 the International Telecommunication Union
(ITU) mandated Morse code proficiency as part of the amateur radio licensing procedure worldwide. However, the World Radiocommunication Conference of 2003 (WRC-03) made the Morse code requirement for amateur radio licensing optional. Many countries subsequently removed the Morse requirement from their licence requirements.
Until 1991, a demonstration of the ability to send and receive Morse code at five words per minute (WPM) based upon the PARIS standard word was required to receive an amateur radio license for use in the United States from the Federal Communications Commission
. Demonstration of this ability was still required for the privilege to use the HF bands
. Until 2000, proficiency at the 20 WPM level based upon the PARIS standard word was required to receive the highest level of amateur license (Extra Class); effective April 15, 2000, the FCC reduced the Extra Class requirement to five WPM. Finally, effective on February 23, 2007, the FCC eliminated the Morse code proficiency requirements from all amateur radio licenses.
While voice and data transmissions are limited to specific amateur radio bands under U.S. rules, CW is permitted on all amateur bands—LF
, MF
, HF, UHF, and VHF, with one notable exception being the 60 meter band in North America
. In some countries, certain portions of the amateur radio bands are reserved for transmission of Morse code signals only.
The relatively limited speed at which Morse code can be sent led to the development of an extensive number of abbreviations to speed communication. These include prosigns
and Q code
s, plus a restricted standardized format for typical messages. For example, CQ is broadcast to be interpreted as "seek you" (I'd like to converse with anyone who can hear my signal). OM (old man), YL (young lady) and XYL ("ex YL" - wife) are common pronouns. YL or OM is used by an operator when referring to the other operator, XYL or OM is used by an operator when referring to his or her spouse. This use of abbreviations for common terms permits conversation even when the operators speak different languages.
Although the traditional telegraph key
(straight key) is still used by many amateurs, the use of mechanical semi-automatic keyer
s (known as "bugs") and of fully automatic electronic keyer
s is prevalent today. Computer software
is also frequently employed to produce and decode Morse code radio signals.
Operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 WPM. International contests in code copying are still occasionally held. In July 1939 at a contest in Asheville, NC
in the United States
Ted R. McElroy set a still-standing record for Morse copying, 75.2 WPM. In his online book on high speed sending, William Pierpont N0HFF notes some operators may have passed 100 WPM. By this time they are "hearing" phrases and sentences rather than words. The fastest speed ever sent by a straight key was achieved in 1942 by Harry Turner W9YZE (d. 1992) who reached 35 WPM in a demonstration at a U.S. Army base. Today among amateur operators there are several high speed code organizations, one going as high as 60 WPM. Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the American Radio Relay League
, whose awards start at 10 WPM and are available to anyone who can copy the transmitted text. To accurately compare code copying speed records of different eras it is useful to keep in mind that different standard words (50 dot durations versus 60 dot durations) and different interword gaps (5 dot durations versus 7 dot durations) may have been used when determining such speed records. For example speeds run with the CODEX standard word and the PARIS standard may differ by up to 20%.
As of 2010 commercial radiotelegraph licenses using code tests based upon the CODEX standard word are still being issued in the United States by the Federal Communications Commission. Designed for shipboard and coast station operators, they are awarded to applicants who pass written examinations on advanced radio theory and show 20 WPM code proficiency [this requirement is currently waived for "old" (20 WPM) Amateur Extra Class licensees]. However, since 1999 the use of satellite and very high frequency maritime communications systems (GMDSS) have essentially made them obsolete.
Radio navigation aids such as VOR
s and NDB
s for aeronautical use broadcast identifying information in the form of Morse Code, though many VOR stations now also provide voice identification.
Warships, including those of the U.S. Navy, have long used signal lamp
s to exchange messages in Morse code. Modern use continues, in part, as a way to communicate while maintaining radio silence
.
, "· · · — — — · · ·". This can be sent many ways: keying a radio on and off, flashing a mirror, toggling a flashlight and similar methods.
, helping people with a variety of disabilities
to communicate. Morse can be sent by persons with severe motion disabilities, as long as they have some minimal motor control. An original solution to the problem that care takers have to learn to decode has been an electronic typewriter with the codes written on the keys. Codes were sung by users, see the voice typewriter employing morse or votem, Newell and Nabarro, 1968.
Morse code can also be translated by computer and used in a speaking communication aid. In some cases this means alternately blowing into and sucking on a plastic tube ("puff and sip
" interface). An important advantage of Morse code over row column scanning is that, once learned, it does not require to look at a display. Also, it appears faster than scanning.
People with severe motion disabilities in addition to sensory disabilities (e.g. people who are also deaf or blind) can receive Morse through a skin buzzer. .
In one case reported in the radio amateur magazine QST
, an old shipboard radio operator who had a stroke
and lost the ability to speak or write was able to communicate with his physician (a radio amateur) by blinking his eyes in Morse. Another example occurred in 1966 when prisoner of war
Jeremiah Denton
, brought on television by his North Vietnamese captors, Morse-blinked the word TORTURE. In these two cases interpreters were available to understand those series of eye-blinks.
Morse code can be transmitted in a number of ways: originally as electrical pulses along a telegraph wire, but also as an audio tone, a radio signal with short and long tones, or as a mechanical or visual signal (e.g. a flashing light) using devices like an Aldis lamp or a heliograph
.
Morse code is transmitted using just two states (on and off) so it was an early form of a digital
code. Strictly speaking it is not binary
, as there are five fundamental elements (see quinary
). However, this does not mean Morse code cannot be represented as a binary code. In an abstract sense, this is the function that telegraph operators perform when transmitting messages. Working from the above definitions and further defining a 'unit' as a bit
, we can visualize any Morse code sequence as a combination of the following five elements:
Note that this method assumes that dits and dahs are always separated by dot duration gaps, and that gaps are always separated by dits and dahs.
Morse messages are generally transmitted by a hand-operated device such as a telegraph key
, so there are variations introduced by the skill of the sender and receiver — more experienced operators can send and receive at faster speeds. In addition, individual operators differ slightly, for example using slightly longer or shorter dashes or gaps, perhaps only for particular characters. This is called their "fist", and receivers can recognize specific individuals by it alone. A good operator who sends clearly and is easy to copy is said to have a "good fist". A "poor fist" is a characteristic of sloppy or hard to copy Morse code.
The measure of the speed of Morse code is wpm
, according to either the PARIS standard or alternatively the CODEX standard, which defines the speed of Morse transmission as the timing needed to send either the word "PARIS" or the word "CODEX" a given number of times per minute. The word PARIS was used because it was felt to be representative of a typical text in the English language, and the choice was also influenced by the fact that the decision was taken at the International Telegraph Conference in Paris 1865. The word CODEX was chosen because it was thought to be typical of randomly selected five character code groups. Generally in Morse code measurements 'characters' is meant to include all of the alphabetic 'letters' plus 'numbers' plus 'punctuation marks', and certain so-called 'prosigns'.
In the past, the word PARIS was used to determine the speed of International Morse for amateur radio operator code tests by the United States Federal Communications Commission (FCC) or the FCC Volunteer Examiners. Amateur radio Morse test candidates were tested based upon their ability to simply listen to English plain language messages in code and to later answer multiple choice questions about the content of the message. i.e. 100% accurate copy and recording on paper of the actual characters being sent was not required to pass amateur radio operator Morse tests.
Typically in the United States the word "CODEX" is still used by the FCC for determining the wpm speed of Morse code for commercial radio telegraph operator tests, i.e. for the FCC T3, T2 and T1 Radiotelegraph operator licenses. Commercial radiotelegraph candidates are tested on their ability to copy five character randomized code groups by ear while simultaneously recording the characters on paper with 100% accuracy by either; manually writing on paper with pencil, or alternatively, by manually typing on a standard typewriter. Unlike the amateur code tests, perfect recording on paper of all characters sent by code is required by commercial operator Morse code tests.
Measured in dot periods or dot durations, the number of dot durations in the standard word PARIS is 43, while the number of dot durations in the standard word CODEX is 53. Adding the current standard inter-word gap of 7 dot durations to each of these numbers results in a total word length of 50 dot durations (43+7) for PARIS and a total word length of 60 dot durations (53+7) for CODEX. Consequently the ratio of the same wpm code speeds using the two different standard words is 6/5 = 1.2.
Stated in words, CODEX based nominal wpm speeds are 20% (6/5 times) faster than PARIS based nominal wpm speeds.
Thus commercial operators are tested at a wpm speed 20% faster than amateur radio operators were tested at the same 'nominal' wpm speeds. For example the 20 wpm speed test for the FCC T2 commercial operator test was actually 24 wpm as compared to the FCC Amateur Extra Class 20 wpm test speed. Commercial test candidates are required to record 100% accurate copy on paper for at least 1 minute of 5 minutes sent, while the amateur test candidates, copying at a speed 20% slower than commercial operators, were only required to understand 3 minutes of plain English without the requirement for 100% accurate recording of the characters copied. Although many amateur Morse operators exhibit superb code copying abilities, as might be expected from the test requirement differences between commercial and amateur code tests, there is a substantially more difficult level of code copying ability required of commercial operator test candidates than amateur operator test candidates.
In the past the interword gap was not always standardized. Today the length of the reference word PARIS is 50 units (including 7 units of word spacing). At the Paris Conference the standard word spacing was specified to be only 5 units, making the total length of the reference word only 48 units, which may be seen in older literature.
The 40 % difference of the two inter word spacing lengths does have an impact on the evaluation of the results of receiving speed competitions performed at various occasions. X WPM at 5 units word spacing is more difficult to copy than the same text sent at the same nominal speed with 7 units word spacing.
Based upon a 50 dot duration standard word such as PARIS, the time for one dot duration or one unit can be computed by the formula:
or
Where: T is the unit time or dot duration in milliseconds, W is the speed in wpm
, and C is the speed in cpm.
Below is an illustration of timing conventions. The phrase "MORSE CODE", in Morse code format, would normally be written something like this, where - represents dahs and · represents dits:
-- --- ·-· ··· · -·-· --- -·· ·
M O R S E C O D E
Next is the exact conventional timing for this phrase, with = representing "signal on", and . representing "signal off", each for the time length of exactly one dit:
1 2 3 4 5 6 7 8
12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
M------ O---------- R------ S---- E C---------- O---------- D------ E
^ ^ ^ ^ ^
| dah dit | |
symbol space letter space word space
Morse code is often spoken or written with "dah" for dashes, "dit" for dots located at the end of a character, and "di" for dots located at the beginning or internally within the character. Thus, the following Morse code sequence:
M O R S E C O D E
-- --- ·-· ··· · (space) -·-· --- -·· ·
is verbally:
Dah-dah dah-dah-dah di-dah-dit di-di-dit dit, Dah-di-dah-dit dah-dah-dah dah-di-dit dit.
Note that there is little point in learning to read written Morse as above; rather, the sounds of all of the letters and symbols need to be learned, for both sending and receiving.
(RTTY) signal when it comes to calculating a link margin
or a link budget
for the simple reason of it possessing variable length dots and dashes as well as variant timing between letters and words. However, because Morse Code when transmitted essentially creates an AM signal (even in on/off keying mode) -- assumptions about signal can be made with respect to similarly timed RTTY signalling.
Because Morse code transmissions employ an on-off keyed
radio signal, it requires less complex transmission equipment than other forms of radio communication. Morse code also requires less signal bandwidth than voice communication, typically 100–150 Hz
, compared to the roughly 2400 Hz used by single-sideband voice
, although at a lower data rate.
Morse code is usually received as a high-pitched audio tone, so transmissions are easier to copy than voice through the noise on congested frequencies, and it can be used in very high noise / low signal environments. The fact that the transmitted power is concentrated into a very limited bandwidth makes it possible to use narrow receiver filters, which suppress or eliminate interference on nearby frequencies. The narrow signal bandwidth also takes advantage of the natural aural selectivity of the human brain, further enhancing weak signal readability. This efficiency makes CW extremely useful for DX (distance) transmissions
, as well as for low-power transmissions (commonly called "QRP operation
", from the Q-code for "reduce power"). There are several amateur clubs that require solid high speed copy, the highest of these has a standard of 60 WPM. The American Radio Relay League
offers a code proficiency certification program that starts at 10 WPM.
, W6TTB, are taught to send and receive letters and other symbols at their full target speed, that is with normal relative timing of the dots, dashes and spaces within each symbol for that speed. However, initially exaggerated spaces between symbols and words are used, to give "thinking time" to make the sound "shape" of the letters and symbols easier to learn. The spacing can then be reduced with practice and familiarity. Another popular teaching method is the Koch method, named after German psychologist Ludwig Koch, which uses the full target speed from the outset, but begins with just two characters. Once strings containing those two characters can be copied with 90% accuracy, an additional character is added, and so on until the full character set is mastered.
In North America, many thousands of individuals have increased their code recognition speed (after initial memorization of the characters) by listening to the regularly scheduled code practice transmissions broadcast by W1AW
, the American Radio Relay League's headquarters station.
In the United Kingdom many people learned the Morse code by means of a series of words or phrases that have the same rhythm as a Morse character. For instance "Q" in Morse is dah - dah - di - dah, which can be memorized by the phrase "God save the Queen"; and the Morse for "F" is di - di - dah - dit, which can be memorized as "Did she like it."
A well known Morse code rhythm from the Second World War period derives from Beethoven's 5th Symphony, the opening phrase of which was regularly played at the beginning of BBC broadcasts. The timing of the notes corresponds to the Morse for "V"; di - di - di - dah and stood for "V for Victory".
There is no standard representation for the exclamation mark (!), although the KW digraph
(— · — · — —) was proposed in the 1980s by the Heathkit
Company (a vendor of assembly kits for amateur radio equipment). While Morse code translation software prefers this version, on-air use is not yet universal as some amateur radio operators in Canada and the USA continue to prefer the older MN digraph (— — — ·) carried over from American landline telegraphy code.
The &, $ and the _ signs are not defined inside the ITU recommendation on Morse code. The $ sign code was represented in the Phillips Code
, a huge collection of abbreviations used on land line telegraphy, as SX. The representation of the &-sign given above is also the Morse prosign for wait.
On May 24, 2004—the 160th anniversary of the first public Morse telegraph transmission—the Radiocommunication Bureau of the International Telecommunication Union (ITU-R
) formally added the @ ("commercial at" or "commat") character to the official Morse character set, using the sequence denoted by the AC digraph (· — — · — ·). This sequence was reportedly chosen to represent "A[T] C[OMMERCIAL]" or a letter "a" inside a swirl represented by a "C". The new character facilitates sending electronic mail addresses by Morse code and is notable since it is the first official addition to the Morse set of characters since World War I
.
Defined in the ITU recommendation.
, Chinese telegraph code
is used to map Chinese characters to four-digit codes and send these digits out using standard Morse code. Korean Morse code uses the SKATS
mapping, originally developed to allow Korean to be typed on western typewriters. SKATS maps hangul
characters to arbitrary letters of the Roman alphabet and has no relationship to pronunciation in Korean
.
table below.
Latin alphabet
The Latin alphabet, also called the Roman alphabet, is the most recognized alphabet used in the world today. It evolved from a western variety of the Greek alphabet called the Cumaean alphabet, which was adopted and modified by the Etruscans who ruled early Rome...
, the Arabic numerals
Arabic numerals
Arabic numerals or Hindu numerals or Hindu-Arabic numerals or Indo-Arabic numerals are the ten digits . They are descended from the Hindu-Arabic numeral system developed by Indian mathematicians, in which a sequence of digits such as "975" is read as a numeral...
and a small set of punctuation and procedural signals as standardized sequences of short and long signals called "dots" and "dashes" respectively, or "dits" and "dahs". Because many non-English natural languages use more than the 26 Roman letters, extensions to the Morse alphabet exist for those languages.
Each character (letter or numeral) is represented by a unique sequence of dots and dashes. The duration of a dash is three times the duration of a dot. Each dot or dash is followed by a short silence, equal to the dot duration. The dot duration is the basic unit of time measurement in code transmission.
Morse code speed is measured in words per minute
Words per minute
Words per minute, commonly abbreviated wpm, is a measure of input or output speed.For the purposes of WPM measurement a word is standardized to five characters or keystrokes. For instance, "I run" counts as one word, but "rhinoceros" counts as two...
(wpm). Characters have differing lengths because they contain differing numbers of dots and dashes. Consequently words also have different lengths in terms of dot duration, even when they contain the same number of characters. For this reason licencing bodies, such as the Federal Communications Commission (FCC) in the US, choose a standard word to measure operator transmission speed. "PARIS" and "CODEX" are two such standard words.
One important feature of Morse code is coding efficiency. The length of each character in Morse is approximately inversely proportional to its frequency of occurrence in English. Thus, the most common letter in English, the letter "E," has the shortest code, a single dot.
A related but different code was originally created for Samuel F. B. Morse's electric telegraph
Telegraphy
Telegraphy is the long-distance transmission of messages via some form of signalling technology. Telegraphy requires messages to be converted to a code which is known to both sender and receiver...
by Alfred Vail in the early 1840s. This code was the forerunner on which modern International Morse code is based. In the 1890s it began to be extensively used for early radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
communication before it was possible to transmit voice. In the late nineteenth and early twentieth century, most high-speed international communication used Morse code on telegraph lines, undersea cables and radio circuits.
Morse code is most popular among amateur radio operator
Amateur radio operator
An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio...
s although it is no longer required for licensing in most countries, including the US. Pilots
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
and air traffic controllers are usually familiar with Morse code and require a basic understanding.
Aeronautical navigational aid
Navigational aid
A navigational aid is any sort of marker which aids the traveler in navigation; the term is most commonly used to refer to nautical or aviation travel...
s, such as VORs
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
and NDBs
Non-directional beacon
A non-directional beacon is a radio transmitter at a known location, used as an aviation or marine navigational aid. As the name implies, the signal transmitted does not include inherent directional information, in contrast to other navigational aids such as low frequency radio range, VHF...
, constantly identify in Morse code. An advantage of Morse code for transmitting over radio waves is that it is able to be received over poor signal conditions that would make voice communications impossible.
Because it can be read by humans without a decoding device, Morse is sometimes a useful alternative
to synthesized speech for sending automated digital data to skilled listeners on voice channels.
Many amateur radio repeater
Amateur radio repeater
An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation...
s, for example, identify with Morse even though they are used for voice
communications.
For emergency signals, Morse code can be sent by way of improvised sources that can be easily "keyed" on and off, making it one of the simplest and most versatile methods of telecommunication
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
.
Development and history
Samuel F. B. Morse
Samuel Finley Breese Morse was an American contributor to the invention of a single-wire telegraph system based on European telegraphs, co-inventor of the Morse code, and an accomplished painter.-Birth and education:...
, the American physicist
Physicist
A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...
Joseph Henry
Joseph Henry
Joseph Henry was an American scientist who served as the first Secretary of the Smithsonian Institution, as well as a founding member of the National Institute for the Promotion of Science, a precursor of the Smithsonian Institution. During his lifetime, he was highly regarded...
, and Alfred Vail developed an electrical telegraph
Electrical telegraph
An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via telecommunication lines or radio. The electromagnetic telegraph is a device for human-to-human transmission of coded text messages....
system. This system sent pulses of electric current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
along wires which controlled an electromagnet
Electromagnet
An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off...
that was located at the receiving end of the telegraph system.
In 1837, William Cooke
William Fothergill Cooke
Sir William Fothergill Cooke was, with Charles Wheatstone, the co-inventor of the Cooke-Wheatstone electrical telegraph, which was patented in May 1837...
and Charles Wheatstone
Charles Wheatstone
Sir Charles Wheatstone FRS , was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope , and the Playfair cipher...
in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
began using an electrical telegraph that also used electromagnets in its receivers. However, in contrast with any system of making sounds of clicks, their system used pointing needles that rotated above alphabetical charts to indicate the letters that were being sent. Cooke and Wheatstone in 1841 built a telegraph that printed the letters from a wheel of typefaces struck by a hammer. This machine was based on their 1840 telegraph and worked well; however, they failed to find customers for this system and only two examples were ever built.
On the other hand, the three Americans' system for telegraphy
Telegraphy
Telegraphy is the long-distance transmission of messages via some form of signalling technology. Telegraphy requires messages to be converted to a code which is known to both sender and receiver...
, which was first used in about 1844, was designed to make indentations on a paper tape when electric currents were received. Morse's original telegraph receiver used a mechanical clockwork to move a paper tape. When an electrical current was received, an electromagnet engaged an armature that pushed a stylus onto the moving paper tape, making an indentation on the tape. When the current was interrupted, the electromagnet retracted the stylus, and that portion of the moving tape remained unmarked.
The Morse code was developed so that operators could translate the indentations marked on the paper tape into text messages. In his earliest code, Morse had planned to only transmit numerals, and use a dictionary to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail to include letters and special characters, so it could be used more generally. Vail determined the frequency of use of letters in the English language
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
by counting the movable type he found in the type-cases of a local newspaper in Morristown
Morristown, New Jersey
Morristown is a town in Morris County, New Jersey, United States. As of the 2010 United States Census, the town population was 18,411. It is the county seat of Morris County. Morristown became characterized as "the military capital of the American Revolution" because of its strategic role in the...
. The shorter marks were called "dots", and the longer ones "dashes", and the letters most commonly used were assigned the shorter sequences of dots and dashes.
In the original Morse telegraphs, the receiver's armature made a clicking noise as it moved in and out of position to mark the paper tape. The telegraph operators soon learned that they could translate the clicks directly into dots and dashes, and write these down by hand, thus making it unnecessary to use a paper tape. When Morse code was adapted to radio communication, the dots and dashes were sent as short and long pulses. It was later found that people became more proficient at receiving Morse code when it is taught as a language that is heard, instead of one read from a page.
To reflect the sounds of Morse code receivers, the operators began to vocalise a dot as "dit", and a dash as "dah". Dots which are not the final element of a character became vocalised as "di". For example, the letter "c" was then vocalised as "dah-di-dah-dit".
In aviation, Morse code in radio systems started to be used on a regular basis in the 1920s. Although previous transmitters were bulky and the spark gap
Spark gap
A spark gap consists of an arrangement of two conducting electrodes separated by a gap usually filled with a gas such as air, designed to allow an electric spark to pass between the conductors. When the voltage difference between the conductors exceeds the gap's breakdown voltage, a spark forms,...
system of transmission was difficult to use, there had been some earlier attempts. In 1910 the U.S. Navy experimented with sending Morse from an airplane. That same year a radio on the Airship America
America (airship)
The America was a non-rigid airship built by Mutin Godard in France in 1906 for Walter Wellman's attempt to reach the North Pole by air. Wellman had been inspired to fly to the pole during a failed overland attempt in 1893. When he saw a French dirigible at the Portsmouth Peace Conference in 1905,...
had been instrumental in coordinating the rescue of its crew. However, there was no aeronautical radio in use during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, and in the 1920s there was no radio system used by such important flights as that of Charles Lindbergh
Charles Lindbergh
Charles Augustus Lindbergh was an American aviator, author, inventor, explorer, and social activist.Lindbergh, a 25-year-old U.S...
from New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
to Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
in 1927. Once he and the Spirit of St. Louis
Spirit of St. Louis
The Spirit of St. Louis is the custom-built, single engine, single-seat monoplane that was flown solo by Charles Lindbergh on May 20–21, 1927, on the first non-stop flight from New York to Paris for which Lindbergh won the $25,000 Orteig Prize.Lindbergh took off in the Spirit from Roosevelt...
were off the ground, Lindbergh was truly alone and incommunicado. On the other hand, when the first airplane flight was made from California to Australia in the 1930s on the Southern Cross (airplane)
Southern Cross (aircraft)
Southern Cross is the name of the Fokker F.VIIb/3m trimotor monoplane which in 1928 was flown by Australian aviator Sir Charles Kingsford Smith and his crew in the first ever trans-Pacific flight, from the mainland United States to Australia, about ....
, one of its four crewmen was its radio operator who communicated with ground stations via radio telegraph
Wireless telegraphy
Wireless telegraphy is a historical term used today to apply to early radio telegraph communications techniques and practices, particularly those used during the first three decades of radio before the term radio came into use....
.
Beginning in the 1930s, both civilian and military pilots were required to be able to use Morse Code, both for use with early communications systems and identification of navigational beacons which transmitted continuous two- or three-letter identifiers in Morse code. Aeronautical chart
Aeronautical chart
An aeronautical chart is a map designed to assist in navigation of aircraft, much as nautical charts do for watercraft, or a roadmap for drivers...
s show the identifier of each navigational aid next to its location on the map.
Radio telegraphy using Morse code was vital during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, especially in carrying messages between the warship
Warship
A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...
s and the naval base
Naval base
A naval base is a military base, where warships and naval ships are deployed when they have no mission at sea or want to restock. Usually ships may also perform some minor repairs. Some naval bases are temporary homes to aircraft that usually stay on the ships but are undergoing maintenance while...
s of the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
, the Kriegsmarine
Kriegsmarine
The Kriegsmarine was the name of the German Navy during the Nazi regime . It superseded the Kaiserliche Marine of World War I and the post-war Reichsmarine. The Kriegsmarine was one of three official branches of the Wehrmacht, the unified armed forces of Nazi Germany.The Kriegsmarine grew rapidly...
, the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
, the Royal Canadian Navy
Royal Canadian Navy
The history of the Royal Canadian Navy goes back to 1910, when the naval force was created as the Naval Service of Canada and renamed a year later by King George V. The Royal Canadian Navy is one of the three environmental commands of the Canadian Forces...
, the Royal Australian Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
, the U.S. Navy, and the U.S. Coast Guard. Long-range ship-to-ship communications was by radio telegraphy, using encrypted messages, because the voice radio systems on ships then were quite limited in both their range, and their security. Radio telegraphy was also extensively used by warplanes, especially by long-range patrol plane
Scout plane
The term scout plane refers to a type of surveillance aircraft, usually of single-engined, two/three seats, shipborne type, and used for the purpose of discovering an enemy position and directing artillery...
s that were sent out by these navies to scout for enemy warships, cargo ships, and troop ships.
In addition, rapidly moving armies in the field could not have fought effectively without radio telegraphy, because they moved more rapidly than telegraph and telephone lines could be erected. This was seen especially in the blitzkrieg
Blitzkrieg
For other uses of the word, see: Blitzkrieg Blitzkrieg is an anglicized word describing all-motorised force concentration of tanks, infantry, artillery, combat engineers and air power, concentrating overwhelming force at high speed to break through enemy lines, and, once the lines are broken,...
offensives of the Nazi German Wehrmacht
Wehrmacht
The Wehrmacht – from , to defend and , the might/power) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the Heer , the Kriegsmarine and the Luftwaffe .-Origin and use of the term:...
in Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
(in 1940), the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
, and in North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
; by the British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...
in North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, and the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
; and by the U.S. Army in France and Belgium (in 1944), and in southern Germany in 1945.
Morse code was used as an international standard for maritime communication until 1999, when it was replaced by the Global Maritime Distress Safety System
Global Maritime Distress Safety System
The Global Maritime Distress and Safety System is an internationally agreed-upon set of safety procedures, types of equipment, and communication protocols used to increase safety and make it easier to rescue distressed ships, boats and aircraft....
. When the French Navy
French Navy
The French Navy, officially the Marine nationale and often called La Royale is the maritime arm of the French military. It includes a full range of fighting vessels, from patrol boats to a nuclear powered aircraft carrier and 10 nuclear-powered submarines, four of which are capable of launching...
ceased using Morse code on January 31, 1997, the final message transmitted was "Calling all. This is our last cry before our eternal silence."
The United States Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
has ceased all use of Morse code on the radio, and no longer monitors any radio frequencies for Morse code transmissions, including the international CW medium frequency (MF) distress frequency of 500 kHz.
International Morse Code
Morse code has been in use for more than 160 years — longer than any other electrical coding system. What is called Morse code today is actually somewhat different from what was originally developed by Vail and Morse. The Modern International Morse code, or continental code, was created by Friedrich Clemens GerkeFriedrich Clemens Gerke
Friedrich Clemens Gerke was a German writer, journalist, musician and pioneer of telegraphy who revised the Morse code in 1848. It is Gerke's notation which is used today.-Life:...
in 1848 and initially used for telegraphy between Hamburg
Hamburg
-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...
and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numeral
Numerical digit
A digit is a symbol used in combinations to represent numbers in positional numeral systems. The name "digit" comes from the fact that the 10 digits of the hands correspond to the 10 symbols of the common base 10 number system, i.e...
s resulting in substantially the modern form of the code. After some minor changes, International Morse Code was standardized at the International Telegraphy Congress in 1865 in Paris, and later International Morse Code made the standard by the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
(ITU). Morse's original code specification, largely limited to use in the United States and Canada, became known as American Morse code
American Morse code
American Morse Code — also known as Railroad Morse—is the latter-day name for the original version of the Morse Code developed in the mid-1840s, by Samuel Morse and Alfred Vail for their electric telegraph...
or railroad code. American Morse code is now seldom used except in historical re-enactments.
Aviation
In aviationAviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, instrument pilots use radio navigation
Radio navigation
Radio navigation or radionavigation is the application of radio frequencies to determine a position on the Earth. Like radiolocation, it is a type of radiodetermination.The basic principles are measurements from/to electric beacons, especially...
aids. To ensure that the stations they are using are serviceable, they all emit a short set of identification letters (usually a two-to-five-letter version of the station name) in Morse code. Station identification letters are shown on air navigation charts. For example, the VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
based at Manchester Airport in England is abbreviated as "MCT", and MCT in Morse code is transmitted on its radio frequency. In some countries, if a VOR station begins malfunctioning it broadcasts "TST" (for "TEST"), which tells pilots
Aviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
and navigator
Navigator
A navigator is the person on board a ship or aircraft responsible for its navigation. The navigator's primary responsibility is to be aware of ship or aircraft position at all times. Responsibilities include planning the journey, advising the Captain or aircraft Commander of estimated timing to...
s that the station is unreliable. In Canada, the ident is removed entirely to signify the navigation aid is not to be used.
Amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
operators, where it is used as the pattern to key a transmitter on and off in the radio communications mode commonly referred to as "continuous wave
Continuous wave
A continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off...
" or "CW". Other keying methods are available in radio telegraphy, such as frequency shift keying.
The original amateur radio operators used Morse code exclusively, since voice-capable radio transmitters did not become commonly available until around 1920. Until 2003 the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
(ITU) mandated Morse code proficiency as part of the amateur radio licensing procedure worldwide. However, the World Radiocommunication Conference of 2003 (WRC-03) made the Morse code requirement for amateur radio licensing optional. Many countries subsequently removed the Morse requirement from their licence requirements.
Until 1991, a demonstration of the ability to send and receive Morse code at five words per minute (WPM) based upon the PARIS standard word was required to receive an amateur radio license for use in the United States from the Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
. Demonstration of this ability was still required for the privilege to use the HF bands
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...
. Until 2000, proficiency at the 20 WPM level based upon the PARIS standard word was required to receive the highest level of amateur license (Extra Class); effective April 15, 2000, the FCC reduced the Extra Class requirement to five WPM. Finally, effective on February 23, 2007, the FCC eliminated the Morse code proficiency requirements from all amateur radio licenses.
While voice and data transmissions are limited to specific amateur radio bands under U.S. rules, CW is permitted on all amateur bands—LF
136 kHz
The 2200 meter or 136 kHz band is the lowest frequency band in which amateur radio operators are allowed to transmit. It is available for use in several countries, and at the 2007 World Radiocommunication Conference , it was made the newest world wide amateur allocation...
, MF
160 meters
Just above the mediumwave broadcast band, 160 meters is the lowest radio frequency band allocation available to amateur radio operators in most countries. Seasoned operators often refer to 160 meters as the Top Band...
, HF, UHF, and VHF, with one notable exception being the 60 meter band in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. In some countries, certain portions of the amateur radio bands are reserved for transmission of Morse code signals only.
The relatively limited speed at which Morse code can be sent led to the development of an extensive number of abbreviations to speed communication. These include prosigns
Prosigns for Morse Code
In Morse code, prosigns or procedural signals are dot/dash sequences that have a special meaning in a transmission: they are a form of control character...
and Q code
Q code
The Q code is a standardized collection of three-letter message encodings, also known as a brevity code, all of which start with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio...
s, plus a restricted standardized format for typical messages. For example, CQ is broadcast to be interpreted as "seek you" (I'd like to converse with anyone who can hear my signal). OM (old man), YL (young lady) and XYL ("ex YL" - wife) are common pronouns. YL or OM is used by an operator when referring to the other operator, XYL or OM is used by an operator when referring to his or her spouse. This use of abbreviations for common terms permits conversation even when the operators speak different languages.
Although the traditional telegraph key
Telegraph key
Telegraph key is a general term for any switching device used primarily to send Morse code. Similar keys are used for all forms of manual telegraphy, such as in electrical telegraph and radio telegraphy.- Types of keys :...
(straight key) is still used by many amateurs, the use of mechanical semi-automatic keyer
Keyer
A keyer is a device for signaling by hand, by way of pressing one or more switches. Modern keyers typically have a large number of switches but not as many as a full-size keyboard; typically between four and fifty. A keyer differs from a keyboard in the sense that there is no "board"; the keys are...
s (known as "bugs") and of fully automatic electronic keyer
Keyer
A keyer is a device for signaling by hand, by way of pressing one or more switches. Modern keyers typically have a large number of switches but not as many as a full-size keyboard; typically between four and fifty. A keyer differs from a keyboard in the sense that there is no "board"; the keys are...
s is prevalent today. Computer software
Computer software
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....
is also frequently employed to produce and decode Morse code radio signals.
Speed records
Asheville, North Carolina
Asheville is a city in and the county seat of Buncombe County, North Carolina, United States. It is the largest city in Western North Carolina, and the 11th largest city in North Carolina. The City is home to the United States National Climatic Data Center , which is the world's largest active...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Ted R. McElroy set a still-standing record for Morse copying, 75.2 WPM. In his online book on high speed sending, William Pierpont N0HFF notes some operators may have passed 100 WPM. By this time they are "hearing" phrases and sentences rather than words. The fastest speed ever sent by a straight key was achieved in 1942 by Harry Turner W9YZE (d. 1992) who reached 35 WPM in a demonstration at a U.S. Army base. Today among amateur operators there are several high speed code organizations, one going as high as 60 WPM. Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the American Radio Relay League
American Radio Relay League
The American Radio Relay League is the largest membership association of amateur radio enthusiasts in the USA. ARRL is a non-profit organization, and was founded in May 1914 by Hiram Percy Maxim of Hartford, Connecticut...
, whose awards start at 10 WPM and are available to anyone who can copy the transmitted text. To accurately compare code copying speed records of different eras it is useful to keep in mind that different standard words (50 dot durations versus 60 dot durations) and different interword gaps (5 dot durations versus 7 dot durations) may have been used when determining such speed records. For example speeds run with the CODEX standard word and the PARIS standard may differ by up to 20%.
Other uses
Radio navigation aids such as VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
s and NDB
Non-directional beacon
A non-directional beacon is a radio transmitter at a known location, used as an aviation or marine navigational aid. As the name implies, the signal transmitted does not include inherent directional information, in contrast to other navigational aids such as low frequency radio range, VHF...
s for aeronautical use broadcast identifying information in the form of Morse Code, though many VOR stations now also provide voice identification.
Warships, including those of the U.S. Navy, have long used signal lamp
Signal lamp
A signal lamp is a visual signaling device for optical communication . Modern signal lamps are a focused lamp which can produce a pulse of light...
s to exchange messages in Morse code. Modern use continues, in part, as a way to communicate while maintaining radio silence
Radio silence
In telecommunications, radio silence is a status in which all fixed or mobile radio stations in an area are asked to stop transmitting for safety or security reasons.The term "radio station" may include anything capable of transmitting a radio signal....
.
Applications for the general public
An important application is signalling for help through SOSSOS
SOS is the commonly used description for the international Morse code distress signal...
, "· · · — — — · · ·". This can be sent many ways: keying a radio on and off, flashing a mirror, toggling a flashlight and similar methods.
Morse code as an assistive technology
Morse code has been employed as an assistive technologyAssistive technology
Assistive technology or adaptive technology is an umbrella term that includes assistive, adaptive, and rehabilitative devices for people with disabilities and also includes the process used in selecting, locating, and using them...
, helping people with a variety of disabilities
Disability
A disability may be physical, cognitive, mental, sensory, emotional, developmental or some combination of these.Many people would rather be referred to as a person with a disability instead of handicapped...
to communicate. Morse can be sent by persons with severe motion disabilities, as long as they have some minimal motor control. An original solution to the problem that care takers have to learn to decode has been an electronic typewriter with the codes written on the keys. Codes were sung by users, see the voice typewriter employing morse or votem, Newell and Nabarro, 1968.
Morse code can also be translated by computer and used in a speaking communication aid. In some cases this means alternately blowing into and sucking on a plastic tube ("puff and sip
Sip-and-puff
Sip-and-Puff or Sip 'n' Puff ' technology is a method used to send signals to a device using air pressure by "sipping" or "puffing" on a straw, tube or "wand." It is primarily used by people who do not have the use of their hands...
" interface). An important advantage of Morse code over row column scanning is that, once learned, it does not require to look at a display. Also, it appears faster than scanning.
People with severe motion disabilities in addition to sensory disabilities (e.g. people who are also deaf or blind) can receive Morse through a skin buzzer. .
In one case reported in the radio amateur magazine QST
QST
QST is a magazine for amateur radio enthusiasts, published by the American Radio Relay League . It is a membership journal that is included in membership with the ARRL. The publisher claims that circulation of QST in the United States is higher than all amateur radio-related publications in the...
, an old shipboard radio operator who had a stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
and lost the ability to speak or write was able to communicate with his physician (a radio amateur) by blinking his eyes in Morse. Another example occurred in 1966 when prisoner of war
Prisoner of war
A prisoner of war or enemy prisoner of war is a person, whether civilian or combatant, who is held in custody by an enemy power during or immediately after an armed conflict...
Jeremiah Denton
Jeremiah Denton
Jeremiah Andrew Denton Jr. is a retired United States Navy rear admiral, naval aviator and a former Republican U.S. senator, for the state of Alabama...
, brought on television by his North Vietnamese captors, Morse-blinked the word TORTURE. In these two cases interpreters were available to understand those series of eye-blinks.
Representation, timing and speeds
International Morse code is composed of five elements:- short mark, dot or 'dit' (·) — 'dot duration' is one unit long
- longer mark, dash or 'dah' (–) — three units long
- inter-element gap between the dots and dashes within a character — one dot duration or one unit long
- short gap (between letters) — three units long
- medium gap (between words) — seven units long
Morse code can be transmitted in a number of ways: originally as electrical pulses along a telegraph wire, but also as an audio tone, a radio signal with short and long tones, or as a mechanical or visual signal (e.g. a flashing light) using devices like an Aldis lamp or a heliograph
Heliograph
A heliograph is a wireless solar telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter...
.
Morse code is transmitted using just two states (on and off) so it was an early form of a digital
Digital
A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...
code. Strictly speaking it is not binary
Binary numeral system
The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...
, as there are five fundamental elements (see quinary
Quinary
Quinary is a numeral system with five as the base. A possible origination of a quinary system is that there are five fingers on either hand. The base five is stated from 0-4...
). However, this does not mean Morse code cannot be represented as a binary code. In an abstract sense, this is the function that telegraph operators perform when transmitting messages. Working from the above definitions and further defining a 'unit' as a bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
, we can visualize any Morse code sequence as a combination of the following five elements:
- short mark, dot or 'dit' (·) — 1
- longer mark, dash or 'dah' (–) — 111
- intra-character gap (between the dots and dashes within a character) — 0
- short gap (between letters) — 000
- medium gap (between words) — 0000000
Note that this method assumes that dits and dahs are always separated by dot duration gaps, and that gaps are always separated by dits and dahs.
Morse messages are generally transmitted by a hand-operated device such as a telegraph key
Telegraph key
Telegraph key is a general term for any switching device used primarily to send Morse code. Similar keys are used for all forms of manual telegraphy, such as in electrical telegraph and radio telegraphy.- Types of keys :...
, so there are variations introduced by the skill of the sender and receiver — more experienced operators can send and receive at faster speeds. In addition, individual operators differ slightly, for example using slightly longer or shorter dashes or gaps, perhaps only for particular characters. This is called their "fist", and receivers can recognize specific individuals by it alone. A good operator who sends clearly and is easy to copy is said to have a "good fist". A "poor fist" is a characteristic of sloppy or hard to copy Morse code.
The measure of the speed of Morse code is wpm
Words per minute
Words per minute, commonly abbreviated wpm, is a measure of input or output speed.For the purposes of WPM measurement a word is standardized to five characters or keystrokes. For instance, "I run" counts as one word, but "rhinoceros" counts as two...
, according to either the PARIS standard or alternatively the CODEX standard, which defines the speed of Morse transmission as the timing needed to send either the word "PARIS" or the word "CODEX" a given number of times per minute. The word PARIS was used because it was felt to be representative of a typical text in the English language, and the choice was also influenced by the fact that the decision was taken at the International Telegraph Conference in Paris 1865. The word CODEX was chosen because it was thought to be typical of randomly selected five character code groups. Generally in Morse code measurements 'characters' is meant to include all of the alphabetic 'letters' plus 'numbers' plus 'punctuation marks', and certain so-called 'prosigns'.
In the past, the word PARIS was used to determine the speed of International Morse for amateur radio operator code tests by the United States Federal Communications Commission (FCC) or the FCC Volunteer Examiners. Amateur radio Morse test candidates were tested based upon their ability to simply listen to English plain language messages in code and to later answer multiple choice questions about the content of the message. i.e. 100% accurate copy and recording on paper of the actual characters being sent was not required to pass amateur radio operator Morse tests.
Typically in the United States the word "CODEX" is still used by the FCC for determining the wpm speed of Morse code for commercial radio telegraph operator tests, i.e. for the FCC T3, T2 and T1 Radiotelegraph operator licenses. Commercial radiotelegraph candidates are tested on their ability to copy five character randomized code groups by ear while simultaneously recording the characters on paper with 100% accuracy by either; manually writing on paper with pencil, or alternatively, by manually typing on a standard typewriter. Unlike the amateur code tests, perfect recording on paper of all characters sent by code is required by commercial operator Morse code tests.
Measured in dot periods or dot durations, the number of dot durations in the standard word PARIS is 43, while the number of dot durations in the standard word CODEX is 53. Adding the current standard inter-word gap of 7 dot durations to each of these numbers results in a total word length of 50 dot durations (43+7) for PARIS and a total word length of 60 dot durations (53+7) for CODEX. Consequently the ratio of the same wpm code speeds using the two different standard words is 6/5 = 1.2.
Stated in words, CODEX based nominal wpm speeds are 20% (6/5 times) faster than PARIS based nominal wpm speeds.
Thus commercial operators are tested at a wpm speed 20% faster than amateur radio operators were tested at the same 'nominal' wpm speeds. For example the 20 wpm speed test for the FCC T2 commercial operator test was actually 24 wpm as compared to the FCC Amateur Extra Class 20 wpm test speed. Commercial test candidates are required to record 100% accurate copy on paper for at least 1 minute of 5 minutes sent, while the amateur test candidates, copying at a speed 20% slower than commercial operators, were only required to understand 3 minutes of plain English without the requirement for 100% accurate recording of the characters copied. Although many amateur Morse operators exhibit superb code copying abilities, as might be expected from the test requirement differences between commercial and amateur code tests, there is a substantially more difficult level of code copying ability required of commercial operator test candidates than amateur operator test candidates.
In the past the interword gap was not always standardized. Today the length of the reference word PARIS is 50 units (including 7 units of word spacing). At the Paris Conference the standard word spacing was specified to be only 5 units, making the total length of the reference word only 48 units, which may be seen in older literature.
The 40 % difference of the two inter word spacing lengths does have an impact on the evaluation of the results of receiving speed competitions performed at various occasions. X WPM at 5 units word spacing is more difficult to copy than the same text sent at the same nominal speed with 7 units word spacing.
Based upon a 50 dot duration standard word such as PARIS, the time for one dot duration or one unit can be computed by the formula:
- T = 1200 / W
or
- T = 6000 / C
Where: T is the unit time or dot duration in milliseconds, W is the speed in wpm
Words per minute
Words per minute, commonly abbreviated wpm, is a measure of input or output speed.For the purposes of WPM measurement a word is standardized to five characters or keystrokes. For instance, "I run" counts as one word, but "rhinoceros" counts as two...
, and C is the speed in cpm.
Below is an illustration of timing conventions. The phrase "MORSE CODE", in Morse code format, would normally be written something like this, where - represents dahs and · represents dits:
-- --- ·-· ··· · -·-· --- -·· ·
M O R S E C O D E
Next is the exact conventional timing for this phrase, with = representing "signal on", and . representing "signal off", each for the time length of exactly one dit:
1 2 3 4 5 6 7 8
12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
M------ O---------- R------ S---- E C---------- O---------- D------ E
.
....
....=.
.=...=.=.=...=........=.
.=....
....
.=.=...=^ ^ ^ ^ ^
| dah dit | |
symbol space letter space word space
Morse code is often spoken or written with "dah" for dashes, "dit" for dots located at the end of a character, and "di" for dots located at the beginning or internally within the character. Thus, the following Morse code sequence:
M O R S E C O D E
-- --- ·-· ··· · (space) -·-· --- -·· ·
is verbally:
Dah-dah dah-dah-dah di-dah-dit di-di-dit dit, Dah-di-dah-dit dah-dah-dah dah-di-dit dit.
Note that there is little point in learning to read written Morse as above; rather, the sounds of all of the letters and symbols need to be learned, for both sending and receiving.
Link budget issues
Morse Code cannot be treated as a classical radioteletypeRadioteletype
Radioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...
(RTTY) signal when it comes to calculating a link margin
Link margin
In a wireless communication system, the link margin, measured in dB, is the difference between the receiver's sensitivity and the actual received power...
or a link budget
Link budget
A link budget is the accounting of all of the gains and losses from the transmitter, through the medium to the receiver in a telecommunication system. It accounts for the attenuation of...
for the simple reason of it possessing variable length dots and dashes as well as variant timing between letters and words. However, because Morse Code when transmitted essentially creates an AM signal (even in on/off keying mode) -- assumptions about signal can be made with respect to similarly timed RTTY signalling.
Because Morse code transmissions employ an on-off keyed
On-off keying
On-off keying the simplest form of amplitude-shift keying modulation that represents digital data as the presence or absence of a carrier wave. In its simplest form, the presence of a carrier for a specific duration represents a binary one, while its absence for the same duration represents a...
radio signal, it requires less complex transmission equipment than other forms of radio communication. Morse code also requires less signal bandwidth than voice communication, typically 100–150 Hz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
, compared to the roughly 2400 Hz used by single-sideband voice
Single-sideband modulation
Single-sideband modulation or Single-sideband suppressed-carrier is a refinement of amplitude modulation that more efficiently uses electrical power and bandwidth....
, although at a lower data rate.
Morse code is usually received as a high-pitched audio tone, so transmissions are easier to copy than voice through the noise on congested frequencies, and it can be used in very high noise / low signal environments. The fact that the transmitted power is concentrated into a very limited bandwidth makes it possible to use narrow receiver filters, which suppress or eliminate interference on nearby frequencies. The narrow signal bandwidth also takes advantage of the natural aural selectivity of the human brain, further enhancing weak signal readability. This efficiency makes CW extremely useful for DX (distance) transmissions
DXing
DXing is the hobby of tuning in and identifying distant radio or television signals, or making two way radio contact with distant stations in amateur radio, citizens' band radio or other two way radio communications. Many DXers also attempt to receive written verifications of reception from the...
, as well as for low-power transmissions (commonly called "QRP operation
QRP operation
In amateur radio, QRP operation means transmitting at reduced power levels while aiming to maximize one's effective range while doing so. The term QRP derives from the standard Q code used in radio communications, where "QRP" and "QRP?" are used to request, "Reduce power," and ask "Should I reduce...
", from the Q-code for "reduce power"). There are several amateur clubs that require solid high speed copy, the highest of these has a standard of 60 WPM. The American Radio Relay League
American Radio Relay League
The American Radio Relay League is the largest membership association of amateur radio enthusiasts in the USA. ARRL is a non-profit organization, and was founded in May 1914 by Hiram Percy Maxim of Hartford, Connecticut...
offers a code proficiency certification program that starts at 10 WPM.
Learning Morse Code
People learning Morse code using the Farnsworth method, named for Donald R. "Russ" Farnsworth, also known by his call signCall sign
In broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...
, W6TTB, are taught to send and receive letters and other symbols at their full target speed, that is with normal relative timing of the dots, dashes and spaces within each symbol for that speed. However, initially exaggerated spaces between symbols and words are used, to give "thinking time" to make the sound "shape" of the letters and symbols easier to learn. The spacing can then be reduced with practice and familiarity. Another popular teaching method is the Koch method, named after German psychologist Ludwig Koch, which uses the full target speed from the outset, but begins with just two characters. Once strings containing those two characters can be copied with 90% accuracy, an additional character is added, and so on until the full character set is mastered.
In North America, many thousands of individuals have increased their code recognition speed (after initial memorization of the characters) by listening to the regularly scheduled code practice transmissions broadcast by W1AW
W1AW
W1AW is both the amateur radio call sign and the primary operating station of the American Radio Relay League . This station, which is commonly called the Hiram Percy Maxim Memorial Station, is located on the grounds of ARRL Headquarters in Newington, Connecticut. It was inspired by Maxim's 1AW...
, the American Radio Relay League's headquarters station.
In the United Kingdom many people learned the Morse code by means of a series of words or phrases that have the same rhythm as a Morse character. For instance "Q" in Morse is dah - dah - di - dah, which can be memorized by the phrase "God save the Queen"; and the Morse for "F" is di - di - dah - dit, which can be memorized as "Did she like it."
A well known Morse code rhythm from the Second World War period derives from Beethoven's 5th Symphony, the opening phrase of which was regularly played at the beginning of BBC broadcasts. The timing of the notes corresponds to the Morse for "V"; di - di - di - dah and stood for "V for Victory".
Letters, numbers, punctuation
| Character | Code | Character | Code | Character | Code | Character | Code | Character | Code | Character | Code |
|---|---|---|---|---|---|---|---|---|---|---|---|
| · — | · — — — | · · · | · — — — — | Period [.] | · — · — · — | Colon Colon (punctuation) The colon is a punctuation mark consisting of two equally sized dots centered on the same vertical line.-Usage:A colon informs the reader that what follows the mark proves, explains, or lists elements of what preceded the mark.... [:] |
— — — · · · | ||||
| — · · · | — · — | — | · · — — — | Comma Comma (punctuation) The comma is a punctuation mark. It has the same shape as an apostrophe or single closing quotation mark in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight but inclined from the vertical, or... [,] |
— — · · — — | Semicolon Semicolon The semicolon is a punctuation mark with several uses. The Italian printer Aldus Manutius the Elder established the practice of using the semicolon to separate words of opposed meaning and to indicate interdependent statements. "The first printed semicolon was the work of ... Aldus Manutius"... [;] |
— · — · — · | ||||
| — · — · | · — · · | · · — | · · · — — | Question mark Question mark The question mark , is a punctuation mark that replaces the full stop at the end of an interrogative sentence in English and many other languages. The question mark is not used for indirect questions... [?] |
· · — — · · | Double dash [=] | — · · · — | ||||
| — · · | — — | · · · — | · · · · — | Apostrophe ['] | · — — — — · | Plus Plus and minus signs The plus and minus signs are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Their use has been extended to many other meanings, more or less analogous... [+] |
· — · — · | ||||
| · | — · | · — — | · · · · · | Exclamation mark Exclamation mark The exclamation mark, exclamation point, or bang, or "dembanger" is a punctuation mark usually used after an interjection or exclamation to indicate strong feelings or high volume , and often marks the end of a sentence. Example: “Watch out!” The character is encoded in Unicode at... [!] |
— · — · — — | Hyphen Hyphen The hyphen is a punctuation mark used to join words and to separate syllables of a single word. The use of hyphens is called hyphenation. The hyphen should not be confused with dashes , which are longer and have different uses, or with the minus sign which is also longer... , Minus Plus and minus signs The plus and minus signs are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Their use has been extended to many other meanings, more or less analogous... [-] |
— · · · · — | ||||
| · · — · | — — — | — · · — | — · · · · | Slash Slash (punctuation) The slash is a sign used as a punctuation mark and for various other purposes. It is now often called a forward slash , and many other alternative names.-History:... [/], Fraction bar Fraction (mathematics) A fraction represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, we specify how many parts of a certain size there are, for example, one-half, five-eighths and three-quarters.A common or "vulgar" fraction, such as 1/2, 5/8, 3/4, etc., consists... |
— · · — · | Underscore Underscore The underscore [ _ ] is a character that originally appeared on the typewriter and was primarily used to underline words... [_] |
· · — — · — | ||||
| — — · | · — — · | — · — — | — — · · · | Parenthesis open [(] | — · — — · | Quotation mark Quotation mark Quotation marks or inverted commas are punctuation marks at the beginning and end of a quotation, direct speech, literal title or name. Quotation marks can also be used to indicate a different meaning of a word or phrase than the one typically associated with it and are often used to express irony... ["] |
· — · · — · | ||||
| · · · · | — — · — | — — · · | — — — · · | Parenthesis closed [)] | — · — — · — | Dollar sign Dollar sign The dollar or peso sign is a symbol primarily used to indicate the various peso and dollar units of currency around the world.- Origin :... [$] |
· · · — · · — | ||||
| · · | · — · | — — — — — | — — — — · | Ampersand Ampersand An ampersand is a logogram representing the conjunction word "and". The symbol is a ligature of the letters in et, Latin for "and".-Etymology:... [&], Wait |
· — · · · | At sign [@] | · — — · — · (=A+C, see below) |
There is no standard representation for the exclamation mark (!), although the KW digraph
Digraph (orthography)
A digraph or digram is a pair of characters used to write one phoneme or a sequence of phonemes that does not correspond to the normal values of the two characters combined...
(— · — · — —) was proposed in the 1980s by the Heathkit
Heathkit
Heathkits were products of the Heath Company, Benton Harbor, Michigan. Their products included electronic test equipment, high fidelity home audio equipment, television receivers, amateur radio equipment, electronic ignition conversion modules for early model cars with point style ignitions, and...
Company (a vendor of assembly kits for amateur radio equipment). While Morse code translation software prefers this version, on-air use is not yet universal as some amateur radio operators in Canada and the USA continue to prefer the older MN digraph (— — — ·) carried over from American landline telegraphy code.
The &, $ and the _ signs are not defined inside the ITU recommendation on Morse code. The $ sign code was represented in the Phillips Code
Phillips Code
The Phillips Code is a shorthand method created in 1879 by Walter P. Phillips for the rapid transmission of press reports by telegraph.The code consists of a dictionary of common words or phrases and their associated abbreviations...
, a huge collection of abbreviations used on land line telegraphy, as SX. The representation of the &-sign given above is also the Morse prosign for wait.
On May 24, 2004—the 160th anniversary of the first public Morse telegraph transmission—the Radiocommunication Bureau of the International Telecommunication Union (ITU-R
ITU-R
The ITU Radiocommunication Sector is one of the three sectors of the International Telecommunication Union and is responsible for radio communication....
) formally added the @ ("commercial at" or "commat") character to the official Morse character set, using the sequence denoted by the AC digraph (· — — · — ·). This sequence was reportedly chosen to represent "A[T] C[OMMERCIAL]" or a letter "a" inside a swirl represented by a "C". The new character facilitates sending electronic mail addresses by Morse code and is notable since it is the first official addition to the Morse set of characters since World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
.
Prosigns
| Character(s) | Code | Character(s) | Code | Character(s) | Code |
|---|---|---|---|---|---|
| Wait | · - · · · | Error | · · · · · · · · | Understood | · · · - · |
| Invitation to transmit | - · - | End of work | · · · - · - | Starting Signal | - · - · - |
Defined in the ITU recommendation.
Non-English extensions to the Morse code
| Character(s) | Code | Character(s) | Code | Character(s) | Code |
|---|---|---|---|---|---|
| ä Ä "Ä" and "ä" are both characters that represent either a letter from several extended Latin alphabets, or the letter A with an umlaut mark or diaeresis.- Independent letter :... (also æ Æ Æ is a grapheme formed from the letters a and e. Originally a ligature representing a Latin diphthong, it has been promoted to the full status of a letter in the alphabets of some languages, including Danish, Faroese, Norwegian and Icelandic... and ą A A is the first letter and a vowel in the basic modern Latin alphabet. It is similar to the Ancient Greek letter Alpha, from which it derives.- Origins :... ) |
· — · — | è È or can be*The letter E with a Grave accent.*In Shakespeare's works, è would be used in the -ed suffix to indicate alternate pronunciation, for example with winged/wingèd, the è would be added to produce a pronunciation of instead of .... (also ł) |
· — · · – | ñ Ñ Ñ is a letter of the modern Latin alphabet, formed by an N with a diacritical tilde. It is used in the Spanish alphabet, Galician alphabet, Asturian alphabet, Basque alphabet, Aragonese old alphabet , Filipino alphabet, Chamorro alphabet and the Guarani alphabet, where it represents... (also ń N N is the fourteenth letter in the basic modern Latin alphabet.- History of the forms :One of the most common hieroglyphs, snake, was used in Egyptian writing to stand for a sound like English ⟨J⟩, because the Egyptian word for "snake" was djet... ) |
— — · — — |
| à À is a letter of the Catalan, French, Galician, Italian, Portuguese, Scottish Gaelic and Vietnamese languages, consisting of the Latin letter A and a grave accent. À is also used in Pinyin transliteration. In most languages, it represents the vowel a. This letter is also a letter in Taos.When... (also å Å Å represents various sounds in several languages. Å is part of the alphabets used for the Alemannic and the Bavarian-Austrian dialects of German... ) |
· — — · — | é É is a letter of the Czech, Hungarian, Icelandic, Kashubian, Luxembourgish, Slovak, and Catalan, Danish, English, French, Galician, Irish, Italian, Occitan, Norwegian, Portuguese, Spanish, Swedish, and Vietnamese language as a variant of the letter “e”... (also đ D with stroke Đ , formed from D with the addition of a bar or stroke through the letter. This is the same modification that was used to create eth , but eth is based on an insular variant of d while đ is based on its usual upright shape... and ę E E is the fifth letter and a vowel in the basic modern Latin alphabet. It is the most commonly used letter in the Czech, Danish, Dutch, English, French, German, Hungarian, Latin, Norwegian, Spanish, and Swedish languages.-History:... ) |
· · — · · | ö Ö "Ö", or "ö", is a character used in several extended Latin alphabets, or the letter O with umlaut to denote the front vowels or . In languages without umlaut, the character is also used as a "O with diaeresis" to denote a syllable break, wherein its pronunciation remains an unmodified .- O-Umlaut... (also ø Ø Ø — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound... and ó Ó is a letter in the Faroese, Hungarian, Icelandic, Kashubian, Polish, Czech, Slovak, and Sorbian languages. This letter also appears in the Catalan, Irish, Occitan, Portuguese, Spanish, Italian and Vietnamese languages as a variant of letter “o”. It is also used in English for other purposes... ) |
— — — · |
| ç Ç is a Latin script letter, used in the Albanian, Azerbaijani, Ligurian, Tatar, Turkish, Turkmen, Kurdish and Zazaki alphabets. This letter also appears in Catalan, French, Friulian, Occitan and Portuguese as a variant of the letter “c”... (also ĉ C Ĉ or ĉ is a consonant in Esperanto orthography, representing the sound .Esperanto orthography uses a diacritic for all four of its postalveolar consonants, as do the Latin-based Slavic alphabets... and ć C Ĉ or ĉ is a consonant in Esperanto orthography, representing the sound .Esperanto orthography uses a diacritic for all four of its postalveolar consonants, as do the Latin-based Slavic alphabets... ) |
— · — · · | ĝ G G is the seventh letter in the basic modern Latin alphabet.-History:The letter 'G' was introduced in the Old Latin period as a variant of ⟨c⟩ to distinguish voiced, from voiceless, . The recorded originator of ⟨g⟩ is freedman Spurius Carvilius Ruga, the first Roman to open a fee-paying school,... |
— — · — · | ŝ S S is the nineteenth letter in the ISO basic Latin alphabet.-History: Semitic Šîn represented a voiceless postalveolar fricative . Greek did not have this sound, so the Greek sigma came to represent... |
· · · — · |
| ch CH -Business:* Bemidji Airlines IATA code* Carolina Herrera, a fashion designer based in New York.-Entertainment and sports:* Channel * College Humor.com, a comedy website... (also š Š The grapheme Š, š is used in various contexts, usually denoting the voiceless postalveolar fricative. In the International Phonetic Alphabet this sound is denoted with , but the lowercase š is used in the Americanist phonetic notation, as well as in the Uralic Phonetic Alphabet.For use in computer... ) |
— — — — | ĥ H H .) is the eighth letter in the basic modern Latin alphabet.-History:The Semitic letter ⟨ח⟩ most likely represented the voiceless pharyngeal fricative . The form of the letter probably stood for a fence or posts.... |
— · — — · (Obsolete) — — — — (New) |
þ ("Thorn") | · — — · · |
| ð Ð A Latin capital letter D with a stroke through its vertical bar is the uppercase form of several different letters:*D with stroke , used in Vietnamese, some South Slavic , Moro and Sami languages... ("Eth") |
· · — — · | ĵ J Ĵ or ĵ is a letter in Esperanto orthography representing the sound .While Esperanto orthography uses a diacritic for its four postalveolar consonants, as do the Latin-based Slavic alphabets, the base letters are Romano-Germanic... |
· — — — · | ü Ü Ü, or ü, is a character which can be either a letter from several extended Latin alphabets, or the letter U with an umlaut or a diaeresis... (also ŭ U U is the twenty-first letter and a vowel in the basic modern Latin alphabet.-History:The letter U ultimately comes from the Semitic letter Waw by way of the letter Y. See the letter Y for details.... ) |
· · — — |
| ś S S is the nineteenth letter in the ISO basic Latin alphabet.-History: Semitic Šîn represented a voiceless postalveolar fricative . Greek did not have this sound, so the Greek sigma came to represent... |
· · · — · · · | ź Z Z is the twenty-sixth and final letter of the basic modern Latin alphabet.-Name and pronunciation:In most dialects of English, the letter's name is zed , reflecting its derivation from the Greek zeta but in American English, its name is zee , deriving from a late 17th century English dialectal... |
— — · · — · | ż Z Z is the twenty-sixth and final letter of the basic modern Latin alphabet.-Name and pronunciation:In most dialects of English, the letter's name is zed , reflecting its derivation from the Greek zeta but in American English, its name is zee , deriving from a late 17th century English dialectal... |
— — · · — |
Non-Latin extensions to Morse code
For ChineseChinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, Chinese telegraph code
Chinese telegraph code
The Chinese Telegraph Code, Chinese Telegraphic Code, or Chinese Commercial Code is a four-digit decimal code for electrically telegraphing messages written with Chinese characters.- Encoding and decoding :...
is used to map Chinese characters to four-digit codes and send these digits out using standard Morse code. Korean Morse code uses the SKATS
SKATS
SKATS stands for Standard Korean Alphabet Transliteration System. It is also known as Korean morse equivalents. Despite the name, SKATS is not a true transliteration system. SKATS maps the hangul characters through Korean Morse code to the same codes in Morse code and back to their equivalents in...
mapping, originally developed to allow Korean to be typed on western typewriters. SKATS maps hangul
Hangul
Hangul,Pronounced or ; Korean: 한글 Hangeul/Han'gŭl or 조선글 Chosŏn'gŭl/Joseongeul the Korean alphabet, is the native alphabet of the Korean language. It is a separate script from Hanja, the logographic Chinese characters which are also sometimes used to write Korean...
characters to arbitrary letters of the Roman alphabet and has no relationship to pronunciation in Korean
Korean language
Korean is the official language of the country Korea, in both South and North. It is also one of the two official languages in the Yanbian Korean Autonomous Prefecture in People's Republic of China. There are about 78 million Korean speakers worldwide. In the 15th century, a national writing...
.
Alternative display of more common characters in International Morse code
Some methods of teaching or learning Morse code use the dichotomic searchDichotomic search
In computer science, a dichotomic search is a search algorithm that operates by selecting between two distinct alternatives at each step. It is a specific type of divide and conquer algorithm...
table below.
See also
- ACP-131ACP-131ACP-131 is the controlling publication for the listing of Q codes and Z codes. It is published by NATO Allied countries, and revised from time to time...
- Chinese telegraph codeChinese telegraph codeThe Chinese Telegraph Code, Chinese Telegraphic Code, or Chinese Commercial Code is a four-digit decimal code for electrically telegraphing messages written with Chinese characters.- Encoding and decoding :...
- The CW Operators' ClubThe CW Operators' ClubThe CW Operators' Club is an international organization, in membership and management, for amateur radio operators who enjoy communicating using Morse Code. The club is commonly known as CWops. Its mission is to foster the use of CW, whether for contesting, DXing, traffic handling, or engaging in...
- Guglielmo MarconiGuglielmo MarconiGuglielmo Marconi was an Italian inventor, known as the father of long distance radio transmission and for his development of Marconi's law and a radio telegraph system. Marconi is often credited as the inventor of radio, and indeed he shared the 1909 Nobel Prize in Physics with Karl Ferdinand...
- High Speed TelegraphyHigh Speed TelegraphyHigh Speed Telegraphy competitions challenge individuals to correctly receive and copy Morse code transmissions sent at very high speeds. It is most popular in Eastern Europe, where it is one of several activities collectively referred to as radiosport...
- InstructographInstructographThe Instructograph was a paper tape-based machine used for the study of Morse code.The paper tape mechanism consisted of two reels which passed a paper tape across a reading device that actuated a set of contacts which changed state dependent on the presence or absence of hole punches in the...
- List of international common standards
- Morse code abbreviationsMorse Code AbbreviationsMorse code abbreviations differ from prosigns for Morse Code in that they observe normal interletter spacing; that is, they are not "run together" the way prosigns are. From 1845 until well into the second half of the 20th century, commercial telegraphic code books were used to shorten telegrams, e.g...
- Morse code mnemonicsMorse Code MnemonicsBecause associating letters and numbers with audible "dits" and "dahs" can be difficult, many people have developed mnemonics to help remember the Morse code equivalent of characters....
- NATO phonetic alphabetNATO phonetic alphabetThe NATO phonetic alphabet, more accurately known as the NATO spelling alphabet and also called the ICAO phonetic or spelling alphabet, the ITU phonetic alphabet, and the international radiotelephony spelling alphabet, is the most widely used spelling alphabet...
- Radiotelegraphy
- Russian Morse codeRussian Morse codeThe Russian Morse code approximates the Morse code for the Latin alphabet. To memorize the codes, mnemonics are used, called "melodies" . A "melody" for a morse code for a character is a phrase which is sung : the syllables with vowels а, о, ы correspond to dashes and sung long, the other...
- Wabun CodeWabun CodeThe is a form of Morse code used to send Japanese text. Unlike International Morse Code, which represents letters of the Roman alphabet, in Wabun each symbol represents a Japanese kana...
- Wireless telegraphyWireless telegraphyWireless telegraphy is a historical term used today to apply to early radio telegraph communications techniques and practices, particularly those used during the first three decades of radio before the term radio came into use....