Morse Code
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Morse code is a method used in
telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
to
encode The Encyclopedia of DNA Elements (ENCODE) is a public research project which aims to identify functional elements in the human genome. ENCODE also supports further biomedical research by "generating community resources of genomics data, software ...
text Text may refer to: Written word * Text (literary theory), any object that can be read, including: **Religious text, a writing that a religious tradition considers to be sacred **Text, a verse or passage from scripture used in expository preachin ...
characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after
Samuel Morse Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor and painter. After having established his reputation as a portrait painter, in his middle age Morse contributed to the invention of a single-wire telegraph ...
, one of the inventors of the
telegraph Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
. International Morse code encodes the 26  basic Latin letters through , one
accented A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word ''diacriti ...
Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits'', and words are separated by a space equal to seven ''dits''. — Annexed to the ''International Telecommunication Convention'', Atlantic City, 1947; revised Paris, 1949. Morse code can be memorized and sent in a form perceptible to the human senses, e.g. via sound waves or visible light, such that it can be directly interpreted by persons trained in the skill. Morse code is usually transmitted by on-off keying of an information-carrying medium such as electric current, radio waves, visible light, or sound waves. The current or wave is present during the time period of the ''dit'' or ''dah'' and absent during the time between ''dits'' and ''dahs''. Since many natural languages use more than the 26 letters of the
Latin alphabet The Latin alphabet or Roman alphabet is the collection of letters originally used by the ancient Romans to write the Latin language. Largely unaltered with the exception of extensions (such as diacritics), it used to write English and the o ...
, Morse alphabets have been developed for those languages, largely by transliteration of existing codes. To increase the efficiency of encoding, Morse code was originally designed so that the length of each symbol is approximately inverse to the frequency of occurrence of the character that it represents in text of the English language. Thus the most common letter in English, the letter , has the shortest code – a single ''dit''. Because the Morse code elements are specified by proportion rather than specific time durations, the code is usually transmitted at the highest rate that the receiver is capable of decoding. Morse code transmission rate (''speed'') is specified in ''groups per minute'', commonly referred to as ''words per minute''.


Development and history


Pre-Morse telegraphs and codes

Early in the nineteenth century, European experimenters made progress with electrical signaling systems, using a variety of techniques including static electricity and electricity from
Voltaic pile upright=1.2, Schematic diagram of a copper–zinc voltaic pile. The copper and zinc discs were separated by cardboard or felt spacers soaked in salt water (the electrolyte). Volta's original piles contained an additional zinc disk at the bottom, ...
s producing
electrochemical Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outc ...
and
electromagnetic In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...
changes. These experimental designs were precursors to practical telegraphic applications. Following the discovery of
electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of ...
by Hans Christian Ørsted in 1820 and the invention of the
electromagnet An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in ...
by
William Sturgeon William Sturgeon (22 May 1783 – 4 December 1850) was an English physicist and inventor who made the first electromagnets, and invented the first practical British electric motor. Early life Sturgeon was born on 22 May 1783 in Whittington, ...
in 1824, there were developments in electromagnetic telegraphy in Europe and America. Pulses of electric current were sent along wires to control an electromagnet in the receiving instrument. Many of the earliest telegraph systems used a single-needle system which gave a very simple and robust instrument. However, it was slow, as the receiving operator had to alternate between looking at the needle and writing down the message. In Morse code, a deflection of the needle to the left corresponded to a ''dit'' and a deflection to the right to a ''dah''. By making the two clicks sound different with one ivory and one metal stop, the single needle device became an audible instrument, which led in turn to the ''Double Plate Sounder'' System. William Cooke and
Charles Wheatstone Sir Charles Wheatstone FRS FRSE DCL LLD (6 February 1802 – 19 October 1875), was an English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for di ...
in
Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...
developed an electrical telegraph that used electromagnets in its receivers. They obtained an English patent in June 1837 and demonstrated it on the London and Birmingham Railway, making it the first commercial telegraph.
Carl Friedrich Gauss Johann Carl Friedrich Gauss (; german: Gauß ; la, Carolus Fridericus Gauss; 30 April 177723 February 1855) was a German mathematician and physicist who made significant contributions to many fields in mathematics and science. Sometimes refer ...
and
Wilhelm Eduard Weber Wilhelm Eduard Weber (; ; 24 October 1804 – 23 June 1891) was a German physicist and, together with Carl Friedrich Gauss, inventor of the first electromagnetic telegraph. Biography of Wilhelm Early years Weber was born in Schlossstrasse i ...
(1833) as well as
Carl August von Steinheil Carl August von Steinheil (12 October 1801 – 14 September 1870) was a German physicist, inventor, engineer and astronomer. Biography Steinheil was born in Ribeauvillé, Alsace. He studied law in Erlangen since 1821. He then studied astronomy i ...
(1837) used codes with varying word lengths for their telegraph systems. In 1841, Cooke and Wheatstone built a telegraph that printed the letters from a wheel of typefaces struck by a hammer.


Samuel Morse and Alfred Vail

The American artist
Samuel Morse Samuel Finley Breese Morse (April 27, 1791 – April 2, 1872) was an American inventor and painter. After having established his reputation as a portrait painter, in his middle age Morse contributed to the invention of a single-wire telegraph ...
, the American
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
Joseph Henry, and mechanical engineer
Alfred Vail Alfred Lewis Vail (September 25, 1807 – January 18, 1859) was an American machinist and inventor. Along with Samuel Morse, Vail was central in developing and commercializing American telegraphy between 1837 and 1844. Vail and Morse were the f ...
developed an
electrical telegraph Electrical telegraphs were point-to-point text messaging systems, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems ...
system. It needed a method to transmit natural language using only electrical pulses and the silence between them. Around 1837, Morse therefore developed an early forerunner to the modern International Morse code. The Morse system for
telegraphy Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
, 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, a spring retracted the stylus and that portion of the moving tape remained unmarked. Morse code was developed so that operators could translate the indentations marked on the paper tape into text messages. In his earliest design for a code, Morse had planned to transmit only numerals, and to use a codebook to look up each word according to the number which had been sent. However, the code was soon expanded by
Alfred Vail Alfred Lewis Vail (September 25, 1807 – January 18, 1859) was an American machinist and inventor. Along with Samuel Morse, Vail was central in developing and commercializing American telegraphy between 1837 and 1844. Vail and Morse were the f ...
in 1840 to include letters and special characters, so it could be used more generally. Vail estimated the frequency of use of letters in the
English language English is a West Germanic language of the Indo-European language family, with its earliest forms spoken by the inhabitants of early medieval England. It is named after the Angles, one of the ancient Germanic peoples that migrated to the is ...
by counting the movable type he found in the type-cases of a local newspaper in Morristown, New Jersey. The shorter marks were called "dots" and the longer ones "dashes", and the letters most commonly used were assigned the shortest sequences of dots and dashes. This code, first used in 1844, became known as ''Morse landline 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. The "American" qualifier was added ...
'', or ''Railroad Morse'', until the end of railroad telegraphy in the U.S. in the 1970s.


Operator-led change from graphical to audible code

In the original Morse telegraph system, 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 the paper tape unnecessary. When Morse code was adapted to radio communication, the dots and dashes were sent as short and long tone pulses. It was later found that people become more proficient at receiving Morse code when it is taught as a language that is heard, instead of one read from a page. With the advent of tones produced by radiotelegraph receivers, the operators began to vocalize a dot as ''dit'', and a dash as ''dah'', to reflect the sounds of Morse code they heard. To conform to normal sending speed, ''dits'' which are not the last element of a code became voiced as ''di''. For example, the letter is voiced as Morse code was sometimes facetiously known as "iddy-umpty", a ''dit'' lampooned as "iddy" and a ''dah'' as "umpty", leading to the word " umpteen".


Gerke's refinement of Morse's code

The Morse code, as specified in the current international standard, ''International Morse Code Recommendation'',
ITU-R The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency sp ...
 M.1677-1, was derived from a much-improved proposal by Friedrich Gerke in 1848 that became known as the "Hamburg alphabet". Gerke changed many of the codepoints, in the process doing away with the different length dashes and different inter-element spaces of American Morse, leaving only two coding elements, the dot and the dash. Codes for
German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
umlauted vowels and were introduced. Gerke's code was adopted in Germany and Austria 1851. This finally led to the International Morse code in 1865. The International Morse code adopted most of Gerke's codepoints. The codes for and were taken from a code system developed by Steinheil. A new codepoint was added for since Gerke did not distinguish between and . Changes were also made to , , and . This left only four codepoints identical to the original Morse code, namely , , and , and the latter two had their ''dahs'' extended to full length. The original American code being compared dates to 1838; the later American code shown in the table was developed in 1844.


Radiotelegraphy and aviation

In the 1890s, Morse code began to be used extensively for early
radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmit ...
communication before it was possible to transmit voice. In the late 19th and early 20th centuries, most high-speed international communication used Morse code on telegraph lines, undersea cables, and radio circuits. Although previous transmitters were bulky and the spark gap system of transmission was dangerous and difficult to use, there had been some early attempts: In 1910, the U.S. Navy experimented with sending Morse from an airplane. However the first regular aviation radiotelegraphy was on
airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...
s, which had space to accommodate the large, heavy radio equipment then in use. The same year, 1910, a radio on the airship ''America'' was instrumental in coordinating the rescue of its crew. During
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, Zeppelin airships equipped with radio were used for bombing and naval scouting, and ground-based radio direction finders were used for airship navigation. Allied airships and military aircraft also made some use of radiotelegraphy. However, there was little aeronautical radio in general use during
World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, and in the 1920s, there was no radio system used by such important flights as that of
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from New York to
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in 1927. Once he and the ''
Spirit of St. Louis The ''Spirit of St. Louis'' (formally the Ryan NYP, registration: N-X-211) is the custom-built, single-engine, single-seat, high-wing monoplane that was flown by Charles Lindbergh on May 20–21, 1927, on the first solo nonstop transatlant ...
'' were off the ground, Lindbergh was truly incommunicado and alone. Morse code in aviation began regular use in the mid-1920s. By 1928, when the first airplane flight was made by the ''Southern Cross'' from California to Australia, one of its four crewmen was a radio operator who communicated with ground stations via
radio telegraph Wireless telegraphy or radiotelegraphy is transmission of text messages by radio waves, analogous to electrical telegraphy using electrical cable, cables. Before about 1910, the term ''wireless telegraphy'' was also used for other experimental t ...
. 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 for identification of navigational beacons that transmitted continuous two- or three-letter identifiers in Morse code.
Aeronautical chart An aeronautical chart is a map designed to assist in the navigation of aircraft, much as nautical charts do for watercraft, or a roadmap does for drivers. Using these charts and other tools, pilots are able to determine their position, safe alt ...
s show the identifier of each navigational aid next to its location on the map. In addition, rapidly moving field armies could not have fought effectively without radiotelegraphy; they moved more quickly than their communications services could put up new telegraph and telephone lines. This was seen especially in the blitzkrieg offensives of the
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Wehrmacht The ''Wehrmacht'' (, ) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the ''Heer'' (army), the '' Kriegsmarine'' (navy) and the ''Luftwaffe'' (air force). The designation "''Wehrmacht''" replaced the previo ...
in
Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
,
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,
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(in 1940), the
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, and in
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; by the
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in
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,
Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
, and the
Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...
; and by the
U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...
in France and Belgium (in 1944), and in southern Germany in 1945.


Maritime flash telegraphy and radio telegraphy

Radiotelegraphy using Morse code was vital during
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, especially in carrying messages between the
warship A warship or combatant ship is a naval ship that is built and primarily intended for naval warfare. Usually they belong to the armed forces of a state. As well as being armed, warships are designed to withstand damage and are usually faster a ...
s and the
naval base A naval base, navy base, or military port is a military base, where warships and naval ships are docked when they have no mission at sea or need to restock. Ships may also undergo repairs. Some naval bases are temporary homes to aircraft that u ...
s of the belligerents. Long-range ship-to-ship communication was by radio telegraphy, using
encrypted In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...
messages because the voice radio systems on ships then were quite limited in both their range and their security. Radiotelegraphy was also extensively used by
warplane A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat: * Combat aircraft are designed to destroy enemy equi ...
s, especially by long-range patrol planes that were sent out by those navies to scout for enemy warships, cargo ships, and troop ships. Morse code was used as an international standard for maritime distress until 1999 when it was replaced by the
Global Maritime Distress and Safety System The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convent ...
. When the
French Navy The French Navy (french: Marine nationale, lit=National Navy), informally , is the maritime arm of the French Armed Forces and one of the five military service branches of France. It is among the largest and most powerful naval forces in t ...
ceased using Morse code on January 31, 1997, the final message transmitted was "Calling all. This is our last cry before our eternal silence."


Demise of commercial telegraphy

In the United States the final commercial Morse code transmission was on July 12, 1999, signing off with Samuel Morse's original 1844 message, , and the
prosign Procedural signs or prosigns are shorthand signals used in Morse code radio telegraphy procedure, for the purpose of simplifying and standardizing radio communication protocol. They are separate from Morse code abbreviations, which consist mainly ...
("end of contact"). , the
United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
still trains ten people a year in Morse. The
United States Coast Guard The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mult ...
has ceased all use of Morse code on the radio, and no longer monitors any
radio frequencies Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper ...
for Morse code transmissions, including the international
medium frequency Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300  kilohertz (kHz) to 3  megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the ...
(MF) distress frequency of However, the
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
still grants commercial radiotelegraph operator licenses to applicants who pass its code and written tests. Licensees have reactivated the old California coastal Morse station KPH and regularly transmit from the site under either this
call sign In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigne ...
or as KSM. Similarly, a few U.S.
museum ship A museum ship, also called a memorial ship, is a ship that has been preserved and converted into a museum open to the public for educational or memorial purposes. Some are also used for training and recruitment purposes, mostly for the small numb ...
stations are operated by Morse enthusiasts.


Operator proficiency

Morse code speed is measured in
words per minute Words per minute, commonly abbreviated wpm (sometimes uppercased WPM), is a measure of words processed in a minute, often used as a measurement of the speed of typing, reading or Morse code sending and receiving. Alphanumeric entry Since word ...
() or characters per minute (). Characters have differing lengths because they contain differing numbers of ''dits'' and ''dahs''. Consequently, words also have different lengths in terms of dot duration, even when they contain the same number of characters. For this reason, a standard word is helpful to measure operator transmission speed. and are two such standard words. Operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 . In addition to knowing, understanding, and being able to copy the standard written alpha-numeric and punctuation characters or symbols at high speeds, skilled high speed operators must also be fully knowledgeable of all of the special unwritten Morse code symbols for the standard
Prosigns for Morse code Procedural signs or prosigns are shorthand signals used in Morse code radio telegraphy procedure, for the purpose of simplifying and standardizing radio communication protocol. They are separate from Morse code abbreviations, which consist mainly ...
and the meanings of these special procedural signals in standard Morse code
communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchr ...
. International contests in code copying are still occasionally held. In July 1939 at a contest in
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in the United States Ted R. McElroy W1JYN set a still-standing record for Morse copying, 75.2 . Pierpont (2004) also notes that some operators may have passed 100 . 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  in a demonstration at a U.S. Army base. To accurately compare code copying speed records of different eras it is useful to keep in mind that different standard words (50 dit durations versus 60 dit durations) and different interword gaps (5 dit durations versus 7 dit durations) may have been used when determining such speed records. For example, speeds run with the standard word and the standard may differ by up to 20%. Today among amateur operators there are several organizations that recognize high-speed code ability, one group consisting of those who can copy Morse at 60 . Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the
American Radio Relay League The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of ...
. Their basic award starts at 10  with endorsements as high as 40 , and are available to anyone who can copy the transmitted text. Members of the
Boy Scouts of America The Boy Scouts of America (BSA, colloquially the Boy Scouts) is one of the largest scouting organizations and one of the largest youth organizations in the United States, with about 1.2 million youth participants. The BSA was founded i ...
may put a Morse interpreter's strip on their uniforms if they meet the standards for translating code at 5 . Through May 2013, the First, Second, and Third Class (commercial) Radiotelegraph Licenses using code tests based upon the standard word were still being issued in the United States by the Federal Communications Commission. The First Class license required 20  code group and 25  text code proficiency, the others 16  code group test (five letter blocks sent as simulation of receiving encrypted text) and 20  code text (plain language) test. It was also necessary to pass written tests on operating practice and electronics theory. A unique additional demand for the First Class was a requirement of a year of experience for operators of shipboard and coast stations using Morse. This allowed the holder to be chief operator on board a passenger ship. However, since 1999 the use of satellite and very high-frequency maritime communications systems (
GMDSS The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convent ...
) has made them obsolete. (By that point meeting experience requirement for the First was very difficult.) Currently, only one class of license, the Radiotelegraph Operator License, is issued. This is granted either when the tests are passed or as the Second and First are renewed and become this lifetime license. For new applicants, it requires passing a written examination on electronic theory and radiotelegraphy practices, as well as 16  code-group and 20  text tests. However, the code exams are currently waived for holders of Amateur Extra Class licenses who obtained their operating privileges under the old 20  test requirement.


International Morse code

Morse code has been in use for more than 160 years — longer than any other
electrical Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...
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 Gerke Friedrich Clemens Gerke (22 January 1801 – 21 May 1888) was a German writer, journalist, musician and pioneer of telegraphy who revised the Morse code in 1848. It is Gerke's version of the original (American) Morse code now known as the Interna ...
in 1848 and initially used for telegraphy between
Hamburg (male), (female) en, Hamburger(s), Hamburgian(s) , timezone1 = Central (CET) , utc_offset1 = +1 , timezone1_DST = Central (CEST) , utc_offset1_DST = +2 , postal ...
and
Cuxhaven Cuxhaven (; ) is an independent town and seat of the Cuxhaven district, in Lower Saxony, Germany. The town includes the northernmost point of Lower Saxony. It is situated on the shore of the North Sea at the mouth of the Elbe River. Cuxhaven has ...
in Germany. Gerke changed nearly half of the alphabet and all of the
numerals A numeral is a figure, symbol, or group of figures or symbols denoting a number. It may refer to: * Numeral system used in mathematics * Numeral (linguistics), a part of speech denoting numbers (e.g. ''one'' and ''first'' in English) * Numerical d ...
, providing the foundation for 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 was later made the standard by the
International Telecommunication Union The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
(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 — 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. The "American" qualifier was added ...
or "railroad code". American Morse code is now seldom used except in historical re-enactments.


Aviation

In
aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air ...
, pilots use
radio navigation Radio navigation or radionavigation is the application of radio frequencies to determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of radiodetermination. The basic principles a ...
aids. To ensure that the stations the pilots are using are serviceable, the stations transmit a 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-DME In radio navigation, a VOR/DME is a radio beacon that combines a VHF omnidirectional range (VOR) with a distance-measuring equipment (DME). The VOR allows the receiver to measure its bearing to or from the beacon, while the DME provides the slan ...
based at
Vilo Acuña Airport Vilo Acuña Airport ( es, Aeropuerto Internacional Vilo Acuña) is an international airport serving Cayo Largo del Sur, a small coral island in Cuba. It is located within the special municipality (''municipio especial'') of Isla de la Juventud. ...
in Cayo Largo del Sur, Cuba is coded as "UCL", and UCL in Morse code is transmitted on its radio frequency. In some countries, during periods of maintenance, the facility may radiate a T-E-S-T code () or the code may be removed which tells
pilots An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators, because they a ...
and
navigator A navigator is the person on board a ship or aircraft responsible for its navigation.Grierson, MikeAviation History—Demise of the Flight Navigator FrancoFlyers.org website, October 14, 2008. Retrieved August 31, 2014. The navigator's primar ...
s that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid is not to be used. In the aviation service, Morse is typically sent at a very slow speed of about 5 words per minute. In the U.S., pilots do not actually have to know Morse to identify the transmitter because the dot/dash sequence is written out next to the transmitter's symbol on aeronautical charts. Some modern navigation receivers automatically translate the code into displayed letters.


Amateur radio

International Morse code today is most popular among
amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communic ...
operators, in the mode commonly referred to as "
continuous wave A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. It may refer to e.g. a laser or particle ...
" or "CW". (This name was chosen to distinguish it from the
damped wave Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples inc ...
emissions from spark transmitters, not because the transmission is continuous.) Other keying methods are available in radio telegraphy, such as
frequency-shift keying Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal. The technology is used for communication systems such as telemetry, weather ball ...
. 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 The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
mandated Morse code proficiency as part of the amateur radio licensing procedure worldwide. However, the World Radiocommunication Conference of 2003 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 a minimum of five words per minute () was required to receive an amateur radio license for use in the United States from the
Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction ...
. Demonstration of this ability was still required for the privilege to use the HF bands. Until 2000, proficiency at the 20  level was required to receive the highest level of amateur license (Amateur Extra Class); effective April 15, 2000, the FCC reduced the Extra Class requirement to 5 . 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, Morse code is permitted on all amateur bands — LF, MF, HF, VHF, and UHF. In some countries, certain portions of the amateur radio bands are reserved for transmission of Morse code signals only. 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 Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ''baseband bandwidth''. ...
than voice communication, typically 100–150  Hz, compared to the roughly 2,400 Hz used by single-sideband voice, although at a slower 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 In amateur radio, QRP operation refers to transmitting at reduced power while attempting to maximize one's effective range. QRP operation is a specialized pursuit within the hobby that was first popularized in the early 1920s. QRP operators gener ...
", from the
Q-code The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially ...
for "reduce power"). There are several amateur clubs that require solid high speed copy, the highest of these has a standard of 60 . The
American Radio Relay League The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of ...
offers a code proficiency certification program that starts at 10 . 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,
Q code The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially ...
s, and a set of
Morse code abbreviations Morse code abbreviations are used to speed up Morse communications by foreshortening textual words and phrases. Morse abbreviations are short forms, representing normal textual words and phrases formed from some (fewer) characters taken from the w ...
for typical message components. For example, is broadcast to be interpreted as "seek you" (I'd like to converse with anyone who can hear my signal). (old man), (young lady) and ("ex-young lady" – wife) are common abbreviations. or is used by an operator when referring to the other operator, or is used by an operator when referring to his or her spouse. is "transmitting location" (spoken "my Q.T.H." is "my location"). The use of abbreviations for common terms permits conversation even when the operators speak different languages. Although the traditional
telegraph key A telegraph key is a specialized electrical switch used by a trained operator to transmit text messages in Morse code in a telegraphy system. Keys are used in all forms of electrical telegraph systems, including landline (also called wire) ...
(straight key) is still used by some amateurs, the use of mechanical semi-automatic
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 keyboar ...
s (known as "bugs") and of fully automatic electronic
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 keyboar ...
s is prevalent today.
Software Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work. At the lowest programming level, executable code consists ...
is also frequently employed to produce and decode Morse code radio signals. The
ARRL The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization, and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska o ...
has a readability standard for robot encoders called ''ARRL Farnsworth spacing'' that is supposed to have higher readability for both robot and human decoders. Some programs like WinMorse have implemented the standard.


Other uses

Radio navigation aids such as
VOR VOR or vor may refer to: Organizations * Vale of Rheidol Railway in Wales * Voice of Russia, a radio broadcaster * Volvo Ocean Race, a yacht race Science, technology and medicine * VHF omnidirectional range, a radio navigation aid used in a ...
s and NDBs for aeronautical use broadcast identifying information in the form of Morse Code, though many
VOR VOR or vor may refer to: Organizations * Vale of Rheidol Railway in Wales * Voice of Russia, a radio broadcaster * Volvo Ocean Race, a yacht race Science, technology and medicine * VHF omnidirectional range, a radio navigation aid used in a ...
stations now also provide voice identification. Warships, including those of the
U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...
, have long used
signal lamp Signal lamp training during World War II A signal lamp (sometimes called an Aldis lamp or a Morse lamp) is a semaphore system using a visual signaling device for optical communication, typically using Morse code. The idea of flashing dots and ...
s to exchange messages in Morse code. Modern use continues, in part, as a way to communicate while maintaining
radio silence In telecommunications, radio silence or Emissions Control (EMCON) 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 ca ...
. Automatic Transmitter Identification System (ATIS) uses Morse code to identify uplink sources of analog satellite transmissions. Many amateur radio repeaters identify with Morse, even though they are used for voice communications.


Applications for the general public

An important application is signalling for help through SOS, "". This can be sent many ways: keying a radio on and off, flashing a mirror, toggling a flashlight, and similar methods. The SOS signal is not sent as three separate characters; rather, it is a
prosign Procedural signs or prosigns are shorthand signals used in Morse code radio telegraphy procedure, for the purpose of simplifying and standardizing radio communication protocol. They are separate from Morse code abbreviations, which consist mainly ...
, and is keyed without gaps between characters. Some
Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporatio ...
mobile phones offer an option to alert the user of an incoming text message with the Morse tone "" (representing
SMS Short Message/Messaging Service, commonly abbreviated as SMS, is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile devices exchange short text ...
or Short Message Service). In addition, applications are now available for mobile phones that enable short messages to be input in Morse Code.


Morse code as an assistive technology

Morse code has been employed as an
assistive technology Assistive technology (AT) is a term for assistive, adaptive, and rehabilitative devices for people with disabilities and the elderly. Disabled people often have difficulty performing activities of daily living (ADLs) independently, or even with ...
, helping people with a variety of disabilities to communicate. For example, the Android operating system versions 5.0 and higher allow users to input text using Morse Code as an alternative to a keypad or
handwriting recognition Handwriting recognition (HWR), also known as handwritten text recognition (HTR), is the ability of a computer to receive and interpret intelligible handwritten input from sources such as paper documents, photographs, touch-screens and other dev ...
. 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 caretakers 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. 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 ("
sip-and-puff Sip-and-puff or sip 'n' puff (SNP) is assistive technology used to send signals to a device using air pressure by "sipping" (inhaling) or "puffing" (exhaling) on a straw, tube or "wand." It is primarily used by people who do not have the use o ...
" interface). An important advantage of Morse code over row column scanning is that once learned, it does not require looking at a display. Also, it appears faster than scanning. In one case reported in the radio amateur magazine ''
QST ''QST'' is a magazine for amateur radio enthusiasts, published by the American Radio Relay League (ARRL). It is a membership journal that is included with membership in the ARRL. The publisher claims that circulation of ''QST'' in the United St ...
'', an old shipboard radio operator who had a
stroke A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...
and lost the ability to speak or write could communicate with his physician (a radio amateur) by blinking his eyes in Morse. Two examples of communication in intensive care units were also published in '' QST magazine''. Another example occurred in 1966 when
prisoner of war A prisoner of war (POW) is a person who is held captive by a belligerent power during or immediately after an armed conflict. The earliest recorded usage of the phrase "prisoner of war" dates back to 1610. Belligerents hold prisoners of wa ...
Jeremiah Denton Jeremiah Andrew Denton Jr. (July 15, 1924 – March 28, 2014) was an American politician and military officer who served as a U.S. Senator representing Alabama from 1981 to 1987. He was the first Republican to be popularly elected to a Sen ...
, brought on television by his
North Vietnam North Vietnam, officially the Democratic Republic of Vietnam (DRV; vi, Việt Nam Dân chủ Cộng hòa), was a socialist state supported by the Soviet Union (USSR) and the People's Republic of China (PRC) in Southeast Asia that existed f ...
ese captors, Morse-blinked the word . 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'' (): "dit duration" is one time unit long # long mark, dash or ''dah'' (): three time units long # inter-element gap between the ''dits'' and ''dahs'' within a character: one dot duration or one unit long # short gap (between letters): three time units long # medium gap (between words): seven time units long (formerly five)


Transmission

Morse code can be transmitted in a number of ways: Originally as electrical pulses along a
telegraph Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas p ...
wire, but later extended to an audio tone, a radio signal with short and long tones, or high and low tones, or as a mechanical, audible, or visual signal (e.g. a flashing light) using devices like an
Aldis lamp Signal lamp training during World War II A signal lamp (sometimes called an Aldis lamp or a Morse lamp) is a semaphore system using a visual signaling device for optical communication, typically using Morse code. The idea of flashing dots and da ...
or a
heliograph A heliograph () is a semaphore system that signals by flashes of sunlight (generally using Morse code) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograp ...
, a common flashlight, or even a car horn. Some mine rescues have used pulling on a rope - a short pull for a dot and a long pull for a ''dah''. Morse code is either the first or one of the first of all digital electronic / electrical encoding systems. Morse code is transmitted using just two states (on and off). Morse code may be represented as a binary code, and that is what telegraph operators do when transmitting messages. Working from the above ITU definition and further defining a
bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...
as a dot time, a Morse code sequence may be made from a combination of the following five bit-strings: # short mark, dot or ''dit'' (): 1 # longer mark, dash or ''dah'' (): 111 # intra-character gap (between the ''dits'' and ''dahs'' within a character): 0 # short gap (between letters): 000 # medium gap (between words): 0000000 Note that the marks and gaps alternate: ''Dits'' and ''dahs'' are always separated by one of the gaps, and that the gaps are always separated by a ''dit'' or a ''dah''. Morse messages are generally transmitted by a hand-operated device such as a
telegraph key A telegraph key is a specialized electrical switch used by a trained operator to transmit text messages in Morse code in a telegraphy system. Keys are used in all forms of electrical telegraph systems, including landline (also called wire) ...
, 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 ''dahs'' or gaps, perhaps only for particular characters. This is called their "fist", and experienced operators 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.


Cable code

The very long
time constant In physics and engineering, the time constant, usually denoted by the Greek letter (tau), is the parameter characterizing the response to a step input of a first-order, linear time-invariant (LTI) system.Concretely, a first-order LTI system is a sy ...
s of 19th and early 20th century
submarine communications cable A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables laid beginning in the 1850s carried tel ...
s required a different form of Morse signalling. Instead of keying a voltage on and off for varying times, the dits and dahs were represented by two polarities of voltage impressed on the cable, for a uniform time.


Timing

Below is an illustration of timing conventions. The phrase , 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


Spoken representation

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: is spoken (or sung): For use on radio, 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.


Speed in words per minute

All Morse code elements depend on the dot / ''dit'' length. A ''dah'' is the length of 3 dits (with no gaps between), and spacings are specified in number of ''dit'' lengths. An unambiguous method of specifying the transmission speed is to specify the ''dit'' duration as, for example, 50 milliseconds. Specifying the ''dit'' duration is, however, not the common practice. Usually, speeds are stated in words per minute. That introduces ambiguity because words have different numbers of characters, and characters have different ''dit'' lengths. It is not immediately clear how a specific word rate determines the ''dit'' duration in milliseconds. Some method to standardize the transformation of a word rate to a ''dit'' duration is useful. A simple way to do this is to choose a ''dit'' duration that would send a typical word the desired number of times in one minute. If, for example, the operator wanted a character speed of 13 words per minute, the operator would choose a ''dit'' rate that would send the typical word 13 times in exactly one minute. The typical word thus determines the ''dit'' length. It is common to assume that a word is 5 characters long. There are two common typical words: and . mimics a word rate that is typical of natural language words and reflects the benefits of Morse code's shorter code durations for common characters such as and . offers a word rate that is typical of 5 letter code groups (sequences of random letters). Using the word as a standard, the number of ''dit'' units is 50 and a simple calculation shows that the ''dit'' length at 20 words per minute is 60 milliseconds. Using the word with 60 dit units, the ''dit'' length at 20 words per minute is 50 milliseconds. Because Morse code is usually sent by hand, it is unlikely that an operator could be that precise with the ''dit'' length, and the individual characteristics and preferences of the operators usually override the standards. For commercial radiotelegraph licenses in the United States, the Federal Communications Commission specifies tests for Morse code proficiency in words per minute and in code groups per minute. The
FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...
specifies that a "word" is 5 characters long. The Commission specifies Morse code test elements at 16 code groups per minute, 20 words per minute, 20 code groups per minute, and 25 words per minute. The word per minute rate would be close to the standard, and the code groups per minute would be close to the standard. While the Federal Communications Commission no longer requires Morse code for amateur radio licenses, the old requirements were similar to the requirements for commercial radiotelegraph licenses. A difference between amateur radio licenses and commercial radiotelegraph licenses is that commercial operators must be able to receive code groups of random characters along with plain language text. For each class of license, the code group speed requirement is slower than the plain language text requirement. For example, for the Radiotelegraph Operator License, the examinee must pass a 20 word per minute plain text test and a 16 word per minute code group test. Based upon a 50 dit duration standard word such as , the time for one ''dit'' duration or one unit can be computed by the formula: :~ T = \frac ~ where: is the unit time, or ''dit'' duration in milliseconds, and is the speed in . High-speed telegraphy contests are held; according to the ''
Guinness Book of Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a reference book published annually, listing world ...
'' in June 2005 at the
International Amateur Radio Union The International Amateur Radio Union (IARU) is an international confederation of national organisations that allows a forum for common matters of concern to amateur radio operators worldwide, and collectively represents matters to the Internatio ...
's 6th World Championship in High Speed Telegraphy in
Primorsko Primorsko ( bg, Приморско ) is a town and seaside resort in southeastern Bulgaria, capital of homonymous municipality, part of Burgas Province. A well-known resort on the Bulgarian Black Sea Coast, it is located 52 km south of Burga ...
, Bulgaria, Andrei Bindasov of
Belarus Belarus,, , ; alternatively and formerly known as Byelorussia (from Russian ). officially the Republic of Belarus,; rus, Республика Беларусь, Respublika Belarus. is a landlocked country in Eastern Europe. It is bordered by R ...
transmitted 230 Morse code marks of mixed text in one minute.


Farnsworth speed

Sometimes, especially while teaching Morse code, the timing rules above are changed so two different speeds are used: A character speed and a text speed. The character speed is how fast each individual letter is sent. The text speed is how fast the entire message is sent. For example, individual characters may be sent at a 13 words-per-minute rate, but the intercharacter and interword gaps may be lengthened so the word rate is only 5 words per minute. Using different character and text speeds is, in fact, a common practice, and is used in the Farnsworth method of learning Morse code.


Alternative display of common characters in International Morse code

Some methods of teaching Morse code use a dichotomic search table.


Learning methods

People learning Morse code using the ''Farnsworth method'' are taught to send and receive letters and other symbols at their full target speed, that is with normal relative timing of the ''dits'', ''dahs'', and spaces within each symbol for that speed. The Farnsworth method is named for Donald R. "Russ" Farnsworth, also known by his
call sign In broadcasting and radio communications, a call sign (also known as a call name or call letters—and historically as a call signal—or abbreviated as a call) is a unique identifier for a transmitter station. A call sign can be formally assigne ...
, W6TTB. 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, invented in 1935 by the German engineer and former stormtrooper 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 is both the amateur radio call sign and the primary operating station of the American Radio Relay League (ARRL). This station, which is commonly called the Hiram Percy Maxim Memorial Station, is located on the grounds of ARRL Headquarters in ...
, the American Radio Relay League's headquarters station., the United States military taught Morse code as an 81-day self-paced course, having phased out more traditional classes.


Mnemonics

Visual mnemonic charts have been devised over the ages.
Baden-Powell Lieutenant-General Robert Stephenson Smyth Baden-Powell, 1st Baron Baden-Powell, ( ; (Commonly pronounced by others as ) 22 February 1857 – 8 January 1941) was a British Army officer, writer, founder and first Chief Scout of the wor ...
included one in the
Girl Guides Girl Guides (known as Girl Scouts in the United States and some other countries) is a worldwide movement, originally and largely still designed for girls and women only. The movement began in 1909 when girls requested to join the then-grassroot ...
handbook in 1918. 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, in Morse is which can be memorized by the phrase "
God Save the Queen "God Save the King" is the national and/or royal anthem of the United Kingdom, most of the Commonwealth realms, their territories, and the British Crown Dependencies. The author of the tune is unknown and it may originate in plainchant, bu ...
", and the Morse for is which can be memorized as "Did she like it?"


Letters, numbers, punctuation, prosigns for Morse code and non-Latin variants

:


Prosigns

Prosigns for Morse code are special (usually) unwritten procedural signals or symbols that are used to indicate changes in
communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchr ...
status or white space text formatting actions.


Symbol representations

The symbols ''! ''$ and ''&are not defined inside the official
ITU-R The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency sp ...
''International Morse Code Recommendation'', but informal conventions for them exist. (The ''@symbol was formally added in 2004.) ; Exclamation mark : There is no standard representation for the exclamation mark ''! although the digraph () was proposed in the 1980s by the
Heathkit Heathkit is the brand name of kits and other electronic products produced and marketed by the Heath Company. The products over the decades have included electronic test equipment, high fidelity home audio equipment, television receivers, amateu ...
Company. While Morse code translation software prefers the Heathkit version, on-air use is not yet universal as some amateur radio operators in North America and the Caribbean continue to use the older digraph () copied over from American Morse landline code. ; Currency symbols : The ITU has never formally codified any
currency symbol A currency symbol or currency sign is a graphic symbol used to denote a currency unit. Usually it is defined by the monetary authority, like the national central bank for the currency concerned. In formatting, the symbol can use various format ...
s into Morse code: The unambiguous
ISO 4217 ISO 4217 is a standard published by the International Organization for Standardization (ISO) that defines alpha codes and numeric codes for the representation of currencies and provides information about the relationships between individual cu ...
currency codes are preferred for transmission. : The ''$sign code was represented in the
Phillips Code The Phillips Code is a brevity code (shorthand) created in 1879 by Walter P. Phillips (then of the Associated Press) for the rapid transmission of press reports by telegraph. It defined hundreds of abbreviations and initialisms for commonly us ...
as two characters "", which became merged into (). ; Ampersand : The suggested unofficial encoding of the ampersand ''&sign listed above, often shown as , is also the official Morse
prosign Procedural signs or prosigns are shorthand signals used in Morse code radio telegraphy procedure, for the purpose of simplifying and standardizing radio communication protocol. They are separate from Morse code abbreviations, which consist mainly ...
for ''wait''. In addition, the American Morse encoding for an ampersand () was similar to () and
hams Ham is pork from a leg cut that has been preserved by wet or dry curing, with or without smoking."Bacon: Bacon and Ham Curing" in ''Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 2, p. 39. As a processed meat, the term "ham ...
have near universally carried over this use as an abbreviation for "and" (e.g. ''the weather here is cold and rainy''). ; Keyboard "at" sign : On 24 May 2004 – the 160th anniversary of the first public Morse telegraph transmission – the Radiocommunication Bureau of the International Telecommunication Union (
ITU-R The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications. Its role is to manage the international radio-frequency sp ...
) formally added the ''@("
commercial at The at sign, , is normally read aloud as "at"; it is also commonly called the at symbol, commercial at, or address sign. It is used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 per widget = £14), but ...
" or "commat") character to the official Morse character set, using the sequence denoted by the digraph:  . : This sequence was reported to have been chosen to represent "A C mmercial, or a letter "a" inside a swirl represented by a letter "C". The new character facilitates sending e‑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 (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
.


Non-Latin extensions

The typical tactic for creating Morse codes for non-
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
alphabetic scripts has been to begin by simply using the International Morse codes used for letters whose sound matches the sound of the local alphabet. Because Gerke's code was in official use in central Europe, and included many non-
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
characters, none of which conflict with the International Morse standard, it has served as a beginning-point for other languages that use an
alphabet An alphabet is a standardized set of basic written graphemes (called letters) that represent the phonemes of certain spoken languages. Not all writing systems represent language in this way; in a syllabary, each character represents a syll ...
ic script, but require codes for letters not accommodated by International Morse. The usual method has been to first transliterate the sounds represented by the International, and second the Gerke code into the local alphabet, hence Greek, Hebrew, Russian, and Ukrainian Morse codes. If more codes are needed, one can either invent a new code or convert an otherwise unused code from either code set to the non-Latin letter. For example: * in Spanish Morse is , a local code not used in either International or Gerke Morse. * For the Greek letter Ψ, Greek Morse code uses the International Morse code for Q, , which has no corresponding letter in Greek, even though Ψ and Q have no historical, phonetic, or shape relationship. For
Russian Russian(s) refers to anything related to Russia, including: *Russians (, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *Rossiyane (), Russian language term for all citizens and peo ...
and Bulgarian,
Russian Morse code The Russian Morse code approximates the Morse code for the Latin alphabet. It was enacted by the Russian government in 1856. Полное собрание законов Российской Империи. Собрание Второе. Том XX ...
is used to map the Cyrillic characters to four-element codes. Many of the characters are encoded the same way (A, O, E, I, T, M, N, R, K, etc.). The Bulgarian alphabet contains 30 characters, which exactly match all possible combinations of 1, 2, 3, and 4 ''dits'' and ''dahs'' (Russian is used as Bulgarian , Russian is used as Bulgarian ). Russian requires two more codes, for letters Э and Ъ which are each encoded with 5 elements. Non-
alphabet An alphabet is a standardized set of basic written graphemes (called letters) that represent the phonemes of certain spoken languages. Not all writing systems represent language in this way; in a syllabary, each character represents a syll ...
ic scripts require more radical adaption. Japanese Morse code (
Wabun code is a form of Morse code used to send Japanese language in kana characters. Unlike International Morse Code, which represents letters of the Latin script, in Wabun each symbol represents a Japanese kana. For this reason, Wabun code is also someti ...
) has a separate encoding for
kana The term may refer to a number of syllabaries used to write Japanese phonological units, morae. Such syllabaries include (1) the original kana, or , which were Chinese characters (kanji) used phonetically to transcribe Japanese, the most pr ...
script; although many of the codes are used for International Morse, their sounds are mostly unrelated. The Japanese / Wabun code includes special prosigns for switching back-and-forth from International Morse: signals a switch from International Morse to Wabun, and to return from Wabun to International Morse. For
Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of ...
,
Chinese telegraph code The Chinese telegraph code, Chinese telegraphic code, or Chinese commercial code ( or ) is a four-digit decimal code (character encoding) for electrically telegraphing messages written with Chinese characters. Encoding and decoding A codebook ...
is used to map
Chinese characters Chinese characters () are logograms developed for the writing of Chinese. In addition, they have been adapted to write other East Asian languages, and remain a key component of the Japanese writing system where they are known as ''kanji' ...
to four-digit codes and send these digits out using standard Morse code. Korean Morse code uses the
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 co ...
mapping, originally developed to allow Korean to be typed on western typewriters. SKATS maps
hangul The Korean alphabet, known as Hangul, . Hangul may also be written as following South Korea's standard Romanization. ( ) in South Korea and Chosŏn'gŭl in North Korea, is the modern official writing system for the Korean language. The let ...
characters to arbitrary letters of the
Latin script The Latin script, also known as Roman script, is an alphabetic writing system based on the letters of the classical Latin alphabet, derived from a form of the Greek alphabet which was in use in the ancient Greek city of Cumae, in southern Italy ...
and has no relationship to pronunciation in
Korean Korean may refer to: People and culture * Koreans, ethnic group originating in the Korean Peninsula * Korean cuisine * Korean culture * Korean language **Korean alphabet, known as Hangul or Chosŏn'gŭl **Korean dialects and the Jeju language ** ...
.


Unusual variants

During early World War I (1914–1916), Germany briefly experimented with 'dotty' and 'dashy' Morse, in essence adding a dot or a dash at the end of each Morse symbol. Each one was quickly broken by Allied SIGINT, and standard Morse was restored by Spring 1916. Only a small percentage of Western Front (
North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...
and
Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
) traffic was in 'dotty' or 'dashy' Morse during the entire war. In popular culture, this is mostly remembered in the book ''
The Codebreakers ''The Codebreakers – The Story of Secret Writing'' () is a book by David Kahn, published in 1967, comprehensively chronicling the history of cryptography from ancient Egypt to the time of its writing. The United States government attempted to h ...
'' by Kahn and in the national archives of the UK and Australia (whose
SIGINT Signals intelligence (SIGINT) is intelligence-gathering by interception of ''signals'', whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication ( ...
operators copied most of this Morse variant). Kahn's cited sources come from the popular press and wireless magazines of the time. Other forms of ''Fractional Morse'' or ''Fractionated Morse'' have emerged.


Decoding software

Decoding software for Morse code ranges from software-defined wide-band radio receivers, coupled to the
Reverse Beacon Network Reverse or reversing may refer to: Arts and media * ''Reverse'' (Eldritch album), 2001 * ''Reverse'' (2009 film), a Polish comedy-drama film * ''Reverse'' (2019 film), an Iranian crime-drama film * ''Reverse'' (Morandi album), 2005 * ''Reverse'' ...
, which decodes signals and detects messages on ham bands, to smartphone applications.


See also


Footnotes


References


External links

* * * * — 200 hours of at increasing speeds plus an ASCII-to-CW file generator program. * Archived a
Ghostarchive
and th
Wayback Machine
* * {{DEFAULTSORT:Morse Code American inventions Latin-script representations 1848 introductions Scoutcraft Amateur radio