127-628: 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 pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined, so such systems are thus not true telegraphs. The earliest true telegraph put into widespread use
254-565: A diplomatic cable , is a confidential communication between a diplomatic mission and the foreign ministry of its parent country. These continue to be called telegrams or cables regardless of the method used for transmission. Passing messages by signalling over distance is an ancient practice. One of the oldest examples is the signal towers of the Great Wall of China . In 400 BC , signals could be sent by beacon fires or drum beats . By 200 BC complex flag signalling had developed, and by
381-524: A cable across the Atlantic Ocean proved much more difficult. The Atlantic Telegraph Company , formed in London in 1856, had several failed attempts. A cable laid in 1858 worked poorly for a few days, sometimes taking all day to send a message despite the use of the highly sensitive mirror galvanometer developed by William Thomson (the future Lord Kelvin ) before being destroyed by applying too high
508-462: A code became voiced as di . For example, the letter L ( ▄ ▄▄▄ ▄ ▄ ) is voiced as di dah di dit . Morse code was sometimes facetiously known as "iddy-umpty", a dit lampooned as "iddy" and a dah as "umpty", leading to the word " umpteen ". The Morse code, as specified in the current international standard, International Morse Code Recommendation , ITU-R M.1677-1,
635-436: A code of the same length making it more machine friendly. The Baudot code was used on the earliest ticker tape machines ( Calahan , 1867), a system for mass distributing information on current price of publicly listed companies. In a punched-tape system, the message is first typed onto punched tape using the code of the telegraph system—Morse code for instance. It is then, either immediately or at some later time, run through
762-578: A code proficiency certification program that starts at 10 WPM . 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 codes , and a set of Morse code abbreviations for typical message components. For example, CQ is broadcast to be interpreted as "seek you" (I'd like to converse with anyone who can hear my signal). The abbreviations OM (old man), YL (young lady), and XYL ("ex-young lady" – wife) are common. YL or OM
889-416: A code system developed by Steinheil. A new codepoint was added for J since Gerke did not distinguish between I and J . Changes were also made to X , Y , and Z . This left only four codepoints identical to the original Morse code, namely E , H , K and N , and the latter two had their dahs extended to full length. The original American code being compared dates to 1838;
1016-550: A codebook to look up each word according to the number which had been sent. However, the code was soon expanded by Alfred Vail 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 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
1143-410: A distance and cablegram means something written via a cable, whereas telegraph implies the process of writing at a distance. Later, a Telex was a message sent by a Telex network, a switched network of teleprinters similar to a telephone network. A wirephoto or wire picture was a newspaper picture that was sent from a remote location by a facsimile telegraph . A diplomatic telegram, also known as
1270-464: A distance of a quarter of a mile. In the 1890s inventor Nikola Tesla worked on an air and ground conduction wireless electric power transmission system , similar to Loomis', which he planned to include wireless telegraphy. Tesla's experiments had led him to incorrectly conclude that he could use the entire globe of the Earth to conduct electrical energy and his 1901 large scale application of his ideas,
1397-473: A formal strategic goal, which became known as the All Red Line . In 1896, there were thirty cable-laying ships in the world and twenty-four of them were owned by British companies. In 1892, British companies owned and operated two-thirds of the world's cables and by 1923, their share was still 42.7 percent. During World War I , Britain's telegraph communications were almost completely uninterrupted while it
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#17327805484701524-522: A good insulator that was both flexible and capable of resisting the ingress of seawater was required. A solution presented itself with gutta-percha , a natural rubber from the Palaquium gutta tree, after William Montgomerie sent samples to London from Singapore in 1843. The new material was tested by Michael Faraday and in 1845 Wheatstone suggested that it should be used on the cable planned between Dover and Calais by John Watkins Brett . The idea
1651-403: A high-voltage wireless power station, now called Wardenclyffe Tower , lost funding and was abandoned after a few years. Telegraphic communication using earth conductivity was eventually found to be limited to impractically short distances, as was communication conducted through water, or between trenches during World War I. Flag semaphore Too Many Requests If you report this error to
1778-408: A method, an early forerunner to the modern International Morse code. The Morse 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
1905-470: A morse key was added to the apparatus to give the operator the same degree of control as in the electric telegraph. Another type of heliograph was the heliostat or heliotrope fitted with a Colomb shutter. The heliostat was essentially a surveying instrument with a fixed mirror and so could not transmit a code by itself. The term heliostat is sometimes used as a synonym for heliograph because of this origin. The Colomb shutter ( Bolton and Colomb , 1862)
2032-439: A single-needle telegraph was adapted to indicate just two messages: "Line Clear" and "Line Blocked". The signaller would adjust his line-side signals accordingly. As first implemented in 1844 each station had as many needles as there were stations on the line, giving a complete picture of the traffic. As lines expanded, a sequence of pairs of single-needle instruments were adopted, one pair for each block in each direction. Wigwag
2159-560: A slow data rate) than voice communication (roughly 2,400~2,800 Hz used by SSB voice ). 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
2286-487: 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. 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
2413-404: 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
2540-662: A substantial distance was by Ronalds in 1816 using an electrostatic generator . Ronalds offered his invention to the British Admiralty , but it was rejected as unnecessary, the existing optical telegraph connecting the Admiralty in London to their main fleet base in Portsmouth being deemed adequate for their purposes. As late as 1844, after the electrical telegraph had come into use, the Admiralty's optical telegraph
2667-503: A system of communication that would allow the central government to receive intelligence and to transmit orders in the shortest possible time. On 2 March 1791, at 11 am, they sent the message "si vous réussissez, vous serez bientôt couverts de gloire" (If you succeed, you will soon bask in glory) between Brulon and Parce, a distance of 16 kilometres (10 mi). The first means used a combination of black and white panels, clocks, telescopes, and codebooks to send their message. In 1792, Claude
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#17327805484702794-464: A telegraph between St Petersburg and Kronstadt , but it was never completed. The first operative electric telegraph ( Gauss and Weber , 1833) connected Göttingen Observatory to the Institute of Physics about 1 km away during experimental investigations of the geomagnetic field. The first commercial telegraph was by Cooke and Wheatstone following their English patent of 10 June 1837. It
2921-517: A telegraph that printed the letters from a wheel of typefaces struck by a hammer. The American artist Samuel Morse , the American physicist Joseph Henry , and mechanical engineer Alfred Vail developed an electrical telegraph system. The simple "on or off" nature of its signals made it desirable to find a method of transmitting natural language using only electrical pulses and the silence between them. Around 1837, Morse therefore developed such
3048-402: A transmission machine which sends the message to the telegraph network. Multiple messages can be sequentially recorded on the same run of tape. The advantage of doing this is that messages can be sent at a steady, fast rate making maximum use of the available telegraph lines. The economic advantage of doing this is greatest on long, busy routes where the cost of the extra step of preparing the tape
3175-446: 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 . The needle clicked each time it moved to the right or left. By making the two clicks sound different (by installing one ivory and one metal stop), transmissions on
3302-401: A voltage. Its failure and slow speed of transmission prompted Thomson and Oliver Heaviside to find better mathematical descriptions of long transmission lines . The company finally succeeded in 1866 with an improved cable laid by SS Great Eastern , the largest ship of its day, designed by Isambard Kingdom Brunel . An overland telegraph from Britain to India was first connected in 1866 but
3429-526: A widely noticed transmission of a wanted-person photograph from Paris to London in 1908 used until the wider distribution of the radiofax. Its main competitors were the Bélinographe by Édouard Belin first, then since the 1930s, the Hellschreiber , invented in 1929 by German inventor Rudolf Hell , a pioneer in mechanical image scanning and transmission. The late 1880s through to the 1890s saw
3556-465: Is a form of flag signalling using a single flag. Unlike most forms of flag signalling, which are used over relatively short distances, wigwag is designed to maximise the distance covered—up to 32 km (20 mi) in some cases. Wigwag achieved this by using a large flag—a single flag can be held with both hands unlike flag semaphore which has a flag in each hand—and using motions rather than positions as its symbols since motions are more easily seen. It
3683-517: Is a telegraph consisting of a line of stations in towers or natural high points which signal to each other by means of shutters or paddles. Signalling by means of indicator pointers was called semaphore . Early proposals for an optical telegraph system were made to the Royal Society by Robert Hooke in 1684 and were first implemented on an experimental level by Sir Richard Lovell Edgeworth in 1767. The first successful optical telegraph network
3810-571: Is a telegraph system using reflected sunlight for signalling. It was mainly used in areas where the electrical telegraph had not been established and generally used the same code. The most extensive heliograph network established was in Arizona and New Mexico during the Apache Wars . The heliograph was standard military equipment as late as World War II . Wireless telegraphy developed in the early 20th century became important for maritime use, and
3937-471: 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 in 1848 and initially used for telegraphy between Hamburg and Cuxhaven in Germany. Gerke changed nearly half of the alphabet and all of the numerals , providing the foundation for the modern form of
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4064-418: 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 . 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
4191-472: Is formed by a sequence of dits and dahs . The dit duration can vary for signal clarity and operator skill, but for any one message, once established it is the basic unit of time measurement in Morse code. The duration of a dah is three times the duration of a dit (although some telegraphers deliberately exaggerate the length of a dah for clearer signalling). Each dit or dah within an encoded character
4318-570: Is most popular among amateur radio operators, in the mode commonly referred to as " continuous wave " or "CW". Other, faster keying methods are available in radio telegraphy, such as frequency-shift keying (FSK). 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 mandated Morse code proficiency as part of
4445-465: Is named after Samuel Morse , one of the early developers of the system adopted for electrical telegraphy . International Morse code encodes the 26 basic Latin letters A to Z , one accented Latin letter ( É ), 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
4572-434: 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. International Morse code today
4699-522: Is outweighed by the cost of providing more telegraph lines. The first machine to use punched tape was Bain's teleprinter (Bain, 1843), but the system saw only limited use. Later versions of Bain's system achieved speeds up to 1000 words per minute, far faster than a human operator could achieve. The first widely used system (Wheatstone, 1858) was first put into service with the British General Post Office in 1867. A novel feature of
4826-478: Is supposed to have higher readability for both robot and human decoders. Some programs like WinMorse have implemented the standard. Radio navigation aids such as VORs and NDBs 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 lamps to exchange messages in Morse code. Modern use continues, in part, as
4953-416: Is taught "like a language", with each code perceived as a whole "word" instead of a sequence of separate dots and dashes, such as might be shown on 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
5080-413: Is used by an operator when referring to the other operator (regardless of their actual age), and XYL or OM (rather than the expected XYM ) is used by an operator when referring to his or her spouse. QTH 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
5207-694: The CODEX standard word and the PARIS 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 WPM . Also, Certificates of Code Proficiency are issued by several amateur radio societies, including the American Radio Relay League . Their basic award starts at 10 WPM with endorsements as high as 40 WPM , and are available to anyone who can copy
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5334-777: The Spirit of St. Louis 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 . 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 charts show
5461-658: The English Channel (1899), from shore to ship (1899) and finally across the Atlantic (1901). A study of these demonstrations of radio, with scientists trying to work out how a phenomenon predicted to have a short range could transmit "over the horizon", led to the discovery of a radio reflecting layer in the Earth's atmosphere in 1902, later called the ionosphere . Radiotelegraphy proved effective for rescue work in sea disasters by enabling effective communication between ships and from ship to shore. In 1904, Marconi began
5588-503: The First Macedonian War . Nothing else that could be described as a true telegraph existed until the 17th century. Possibly the first alphabetic telegraph code in the modern era is due to Franz Kessler who published his work in 1616. Kessler used a lamp placed inside a barrel with a moveable shutter operated by the signaller. The signals were observed at a distance with the newly invented telescope. An optical telegraph
5715-588: The Han dynasty (200 BC – 220 AD) signallers had a choice of lights, flags, or gunshots to send signals. By the Tang dynasty (618–907) a message could be sent 1,100 kilometres (700 mi) in 24 hours. The Ming dynasty (1368–1644) added artillery to the possible signals. While the signalling was complex (for instance, different-coloured flags could be used to indicate enemy strength), only predetermined messages could be sent. The Chinese signalling system extended well beyond
5842-532: The London and Birmingham Railway line's chief engineer. The messages were for the operation of the rope-haulage system for pulling trains up the 1 in 77 bank. The world's first permanent railway telegraph was completed in July 1839 between London Paddington and West Drayton on the Great Western Railway with an electric telegraph using a four-needle system. The concept of a signalling "block" system
5969-700: 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. Radiotelegraphy using Morse code was vital during World War II , especially in carrying messages between the warships and the naval bases of the belligerents. Long-range ship-to-ship communication
6096-725: The prosign SK ("end of contact"). As of 2015 , the United States Air Force still trains ten people a year in Morse. 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 medium frequency (MF) distress frequency of 500 kHz . However, the Federal Communications Commission still grants commercial radiotelegraph operator licenses to applicants who pass its code and written tests. Licensees have reactivated
6223-420: 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 airships , 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
6350-637: The American Southwest due to its clear air and mountainous terrain on which stations could be located. It was found necessary to lengthen the morse dash (which is much shorter in American Morse code than in the modern International Morse code) to aid differentiating from the morse dot. Use of the heliograph declined from 1915 onwards, but remained in service in Britain and British Commonwealth countries for some time. Australian forces used
6477-533: The British government followed—by March 1897, Marconi had transmitted Morse code signals over a distance of about 6 km ( 3 + 1 ⁄ 2 mi) across Salisbury Plain . On 13 May 1897, Marconi, assisted by George Kemp, a Cardiff Post Office engineer, transmitted the first wireless signals over water to Lavernock (near Penarth in Wales) from Flat Holm . His star rising, he was soon sending signals across
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#17327805484706604-701: 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 low , MF high , 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 equipment than other radio transmission modes . Morse code also uses less bandwidth (typically only 100–150 Hz wide, although only for
6731-644: The Great Wall. Signal towers away from the wall were used to give early warning of an attack. Others were built even further out as part of the protection of trade routes, especially the Silk Road . Signal fires were widely used in Europe and elsewhere for military purposes. The Roman army made frequent use of them, as did their enemies, and the remains of some of the stations still exist. Few details have been recorded of European/Mediterranean signalling systems and
6858-532: The International code used everywhere else, including all ships at sea and sailing in North American waters. Morse's version became known as American Morse code or railroad code , and is now almost never used, with the possible exception of historical re-enactments. In aviation , pilots use radio navigation aids. To allow pilots to ensure that the stations they intend to use are serviceable,
6985-411: The Morse system connected Baltimore to Washington , and by 1861 the west coast of the continent was connected to the east coast. The Cooke and Wheatstone telegraph , in a series of improvements, also ended up with a one-wire system, but still using their own code and needle displays . The electric telegraph quickly became a means of more general communication. The Morse system was officially adopted as
7112-630: 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 WPM code-group and 20 WPM 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 WPM test requirement. Morse codes of one version or another have been in use for more than 160 years — longer than any other electrical message encoding system. What
7239-552: The United States from the Federal Communications Commission . Demonstration of this ability was still required for the privilege to use the shortwave bands . Until 2000, proficiency at the 20 WPM level was required to receive the highest level of amateur license (Amateur Extra Class); effective April 15, 2000, in the FCC reduced the Extra Class requirement to 5 WPM . Finally, effective on February 23, 2007,
7366-527: The Wheatstone system was the use of bipolar encoding . That is, both positive and negative polarity voltages were used. Bipolar encoding has several advantages, one of which is that it permits duplex communication. The Wheatstone tape reader was capable of a speed of 400 words per minute. A worldwide communication network meant that telegraph cables would have to be laid across oceans. On land cables could be run uninsulated suspended from poles. Underwater,
7493-555: The Wikimedia System Administrators, please include the details below. Request from 172.68.168.237 via cp1104 cp1104, Varnish XID 205644664 Upstream caches: cp1104 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 07:55:48 GMT Morse code Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes , or dits and dahs . Morse code
7620-544: 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 license requirements. Until 1991, a demonstration of the ability to send and receive Morse code at a minimum of five words per minute ( WPM ) was required to receive an amateur radio license for use in
7747-574: 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 . 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 piles producing electrochemical and electromagnetic changes. These experimental designs were precursors to practical telegraphic applications. Following
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#17327805484707874-565: The code. After some minor changes to the letters and a complete revision of the numerals, International Morse Code was standardized by the International Telegraphy Congress in 1865 in Paris, and later became the standard adopted by the International Telecommunication Union (ITU). Morse and Vail's final code specification, however, was only really used only for land-line telegraphy in the United States and Canada, with
8001-436: The consensus was that these new waves (similar to light) would be just as short range as light, and, therefore, useless for long range communication. At the end of 1894, the young Italian inventor Guglielmo Marconi began working on the idea of building a commercial wireless telegraphy system based on the use of Hertzian waves (radio waves), a line of inquiry that he noted other inventors did not seem to be pursuing. Building on
8128-411: The coordinates of the letter of the alphabet being transmitted. The number of said torches held up signalled the grid square that contained the letter. There is no definite record of the system ever being used, but there are several passages in ancient texts that some think are suggestive. Holzmann and Pehrson, for instance, suggest that Livy is describing its use by Philip V of Macedon in 207 BC during
8255-516: The discovery and then development of a newly understood phenomenon into a form of wireless telegraphy , called Hertzian wave wireless telegraphy, radiotelegraphy, or (later) simply " radio ". Between 1886 and 1888, Heinrich Rudolf Hertz published the results of his experiments where he was able to transmit electromagnetic waves (radio waves) through the air, proving James Clerk Maxwell 's 1873 theory of electromagnetic radiation . Many scientists and inventors experimented with this new phenomenon but
8382-407: The discovery of electromagnetism by Hans Christian Ørsted in 1820 and the invention of the electromagnet by William Sturgeon 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
8509-456: The earliest electrical telegraphs. A telegraph message sent by an electrical telegraph operator or telegrapher using Morse code (or a printing telegraph operator using plain text) was known as a telegram. A cablegram was a message sent by a submarine telegraph cable, often shortened to "cable" or "wire". The suffix -gram is derived from ancient Greek: γραμμα ( gramma ), meaning something written, i.e. telegram means something written at
8636-480: The efficiency of transmission, Morse code was originally designed so that the duration 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 E , has the shortest code – a single dit . Because the Morse code elements are specified by proportion rather than specific time durations,
8763-533: The erroneous belief that there was an electrified atmospheric stratum accessible at low altitude. They thought atmosphere current, connected with a return path using "Earth currents" would allow for wireless telegraphy as well as supply power for the telegraph, doing away with artificial batteries. A more practical demonstration of wireless transmission via conduction came in Amos Dolbear 's 1879 magneto electric telephone that used ground conduction to transmit over
8890-415: The extensive definition used by Chappe, Morse argued that the term telegraph can strictly be applied only to systems that transmit and record messages at a distance. This is to be distinguished from semaphore , which merely transmits messages. Smoke signals, for instance, are to be considered semaphore, not telegraph. According to Morse, telegraph dates only from 1832 when Pavel Schilling invented one of
9017-414: The facility may instead transmit the signal TEST ( ▄▄▄ ▄ ▄ ▄ ▄ ▄▄▄ ), or the identification may be removed, which tells pilots and navigators that the station is unreliable. In Canada, the identification is removed entirely to signify the navigation aid
9144-621: The first commercial service to transmit nightly news summaries to subscribing ships, which could incorporate them into their on-board newspapers. A regular transatlantic radio-telegraph service was finally begun on 17 October 1907. Notably, Marconi's apparatus was used to help rescue efforts after the sinking of RMS Titanic . Britain's postmaster-general summed up, referring to the Titanic disaster, "Those who have been saved, have been saved through one man, Mr. Marconi...and his marvellous invention." The successful development of radiotelegraphy
9271-552: The following years, mostly for military purposes, but the first device to become widely used was a heliograph with a moveable mirror ( Mance , 1869). The system was used by the French during the 1870–71 siege of Paris , with night-time signalling using kerosene lamps as the source of light. An improved version (Begbie, 1870) was used by British military in many colonial wars, including the Anglo-Zulu War (1879). At some point,
9398-612: The frequently used vowel O . 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 umlauted vowels and CH were introduced. Gerke's code was adopted in Germany and Austria in 1851. This finally led to the International Morse code in 1865. The International Morse code adopted most of Gerke's codepoints. The codes for O and P were taken from
9525-650: The ground without any wires connecting the stations. Other attempts were made to send the electric current through bodies of water, to span rivers, for example. Prominent experimenters along these lines included Samuel F. B. Morse in the United States and James Bowman Lindsay in Great Britain, who in August 1854, was able to demonstrate transmission across a mill dam at a distance of 500 yards (457 metres). US inventors William Henry Ward (1871) and Mahlon Loomis (1872) developed electrical conduction systems based on
9652-662: The heliograph as late as 1942 in the Western Desert Campaign of World War II . Some form of heliograph was used by the mujahideen in the Soviet–Afghan War (1979–1989). A teleprinter is a telegraph machine that can send messages from a typewriter-like keyboard and print incoming messages in readable text with no need for the operators to be trained in the telegraph code used on the line. It developed from various earlier printing telegraphs and resulted in improved transmission speeds. The Morse telegraph (1837)
9779-419: The heliograph to fill in vast, thinly populated areas that were not covered by the electric telegraph. Twenty-six stations covered an area 320 by 480 km (200 by 300 mi). In a test of the system, a message was relayed 640 km (400 mi) in four hours. Miles' enemies used smoke signals and flashes of sunlight from metal, but lacked a sophisticated telegraph code. The heliograph was ideal for use in
9906-552: 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 ) 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
10033-419: The ideas of previous scientists and inventors Marconi re-engineered their apparatus by trial and error attempting to build a radio-based wireless telegraphic system that would function the same as wired telegraphy. He would work on the system through 1895 in his lab and then in field tests making improvements to extend its range. After many breakthroughs, including applying the wired telegraphy concept of grounding
10160-538: 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 Nazi German Wehrmacht in Poland , Belgium , France (in 1940),
10287-409: The later American code shown in the table was developed in 1844. In the 1890s, Morse code began to be used extensively for early radio 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
10414-415: The letter post on price, and competition from the telephone , which removed their speed advantage, drove the telegraph into decline from 1920 onwards. The few remaining telegraph applications were largely taken over by alternatives on the internet towards the end of the 20th century. The word telegraph (from Ancient Greek : τῆλε ( têle ) 'at a distance' and γράφειν ( gráphein ) 'to write')
10541-418: The line at his own expense and agreed that the railway could have free use of it in exchange for the right to open it up to the public. Most of the early electrical systems required multiple wires (Ronalds' system was an exception), but the system developed in the United States by Morse and Vail was a single-wire system. This was the system that first used the soon-to-become-ubiquitous Morse code . By 1844,
10668-443: 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, was what later became known as Morse landline code , American Morse code , or Railroad Morse , until the end of railroad telegraphy in the U.S. in the 1970s. In the original Morse telegraph system, the receiver's armature made a clicking noise as it moved in and out of position to mark
10795-505: The natural aural selectivity of the human brain, further enhancing weak signal readability. This efficiency makes CW extremely useful for DX (long 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
10922-494: The old California coastal Morse station KPH and regularly transmit from the site under either this call sign or as KSM. Similarly, a few U.S. museum ship stations are operated by Morse enthusiasts. Morse code speed is measured in words per minute ( WPM ) or characters per minute ( CPM ). 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
11049-472: The others 16 WPM code group test (five letter blocks sent as simulation of receiving encrypted text) and 20 WPM 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
11176-408: The paper tape. Early 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. Later telegraphy training found that people become more proficient at receiving Morse code when it
11303-399: The possible messages. One of the few for which details are known is a system invented by Aeneas Tacticus (4th century BC). Tacticus's system had water filled pots at the two signal stations which were drained in synchronisation. Annotation on a floating scale indicated which message was being sent or received. Signals sent by means of torches indicated when to start and stop draining to keep
11430-527: The rescue of its crew. During World War I , 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 , 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
11557-538: The same number of characters. For this reason, some standard word is adopted for measuring operators' transmission speeds: Two such standard words in common use are PARIS and CODEX . Operators skilled in Morse code can often understand ("copy") code in their heads at rates in excess of 40 WPM . 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
11684-798: The single needle device became audible as well as visible, which led in turn to the Double Plate Sounder System. William Cooke and Charles Wheatstone in Britain 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 and Wilhelm Eduard Weber (1833) as well as Carl August von Steinheil (1837) used codes with varying word lengths for their telegraph systems. In 1841, Cooke and Wheatstone built
11811-564: 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 , Morse alphabets have been developed for those languages, largely by transliteration of existing codes. To increase
11938-688: The special unwritten Morse code symbols for the standard Prosigns for Morse code and the meanings of these special procedural signals in standard Morse code communications protocol . International contests in code copying are still occasionally held. In July 1939 at a contest in Asheville, North Carolina in the United States, Theodore Roosevelt McElroy ( W1JYN ) set a still-standing record for Morse copying, 75.2 WPM . Pierpont (2004) also notes that 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
12065-576: The standard for continental European telegraphy in 1851 with a revised code, which later became the basis of International Morse Code . However, Great Britain and the British Empire continued to use the Cooke and Wheatstone system, in some places as late as the 1930s. Likewise, the United States continued to use American Morse code internally, requiring translation operators skilled in both codes for international messages. Railway signal telegraphy
12192-546: 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 based at Vilo Acuña Airport in Cayo Largo del Sur, Cuba is identified by " UCL ", and Morse code UCL is repeatedly transmitted on its radio frequency. In some countries, during periods of maintenance,
12319-461: The synchronisation. None of the signalling systems discussed above are true telegraphs in the sense of a system that can transmit arbitrary messages over arbitrary distances. Lines of signalling relay stations can send messages to any required distance, but all these systems are limited to one extent or another in the range of messages that they can send. A system like flag semaphore , with an alphabetic code, can certainly send any given message, but
12446-559: The system is designed for short-range communication between two persons. An engine order telegraph , used to send instructions from the bridge of a ship to the engine room, fails to meet both criteria; it has a limited distance and very simple message set. There was only one ancient signalling system described that does meet these criteria. That was a system using the Polybius square to encode an alphabet. Polybius (2nd century BC) suggested using two successive groups of torches to identify
12573-469: The traditional telegraph key (straight key) is still used by some amateurs, the use of mechanical semi-automatic keyers (informally called "bugs"), and of fully automatic electronic keyers (called "single paddle" and either "double-paddle" or "iambic" keys) is prevalent today. Software is also frequently employed to produce and decode Morse code radio signals. The ARRL has a readability standard for robot encoders called ARRL Farnsworth spacing that
12700-669: The transmitted text. Members of the Boy Scouts of America may put a Morse interpreter's strip on their uniforms if they meet the standards for translating code at 5 WPM . Through May 2013, the First, Second, and Third Class (commercial) Radiotelegraph Licenses using code tests based upon the CODEX standard word were still being issued in the United States by the Federal Communications Commission. The First Class license required 20 WPM code group and 25 WPM text code proficiency,
12827-536: The transmitter and receiver, Marconi was able, by early 1896, to transmit radio far beyond the short ranges that had been predicted. Having failed to interest the Italian government, the 22-year-old inventor brought his telegraphy system to Britain in 1896 and met William Preece , a Welshman, who was a major figure in the field and Chief Engineer of the General Post Office . A series of demonstrations for
12954-445: The two stations to form a complete electrical circuit or "loop". In 1837, however, Carl August von Steinheil of Munich , Germany , found that by connecting one leg of the apparatus at each station to metal plates buried in the ground, he could eliminate one wire and use a single wire for telegraphic communication. This led to speculation that it might be possible to eliminate both wires and therefore transmit telegraph signals through
13081-511: Was a competitor to electrical telegraphy using submarine telegraph cables in international communications. Telegrams became a popular means of sending messages once telegraph prices had fallen sufficiently. Traffic became high enough to spur the development of automated systems— teleprinters and punched tape transmission. These systems led to new telegraph codes , starting with the Baudot code . However, telegrams were never able to compete with
13208-557: Was able to quickly cut Germany's cables worldwide. In 1843, Scottish inventor Alexander Bain invented a device that could be considered the first facsimile machine . He called his invention a "recording telegraph". Bain's telegraph was able to transmit images by electrical wires. Frederick Bakewell made several improvements on Bain's design and demonstrated a telefax machine. In 1855, an Italian priest, Giovanni Caselli , also created an electric telegraph that could transmit images. Caselli called his invention " Pantelegraph ". Pantelegraph
13335-459: Was adopted by Western Union . Early teleprinters used the Baudot code , a five-bit sequential binary code. This was a telegraph code developed for use on the French telegraph using a five-key keyboard ( Baudot , 1874). Teleprinters generated the same code from a full alphanumeric keyboard. A feature of the Baudot code, and subsequent telegraph codes, was that, unlike Morse code, every character has
13462-473: Was appointed Ingénieur-Télégraphiste and charged with establishing a line of stations between Paris and Lille , a distance of 230 kilometres (140 mi). It was used to carry dispatches for the war between France and Austria. In 1794, it brought news of a French capture of Condé-sur-l'Escaut from the Austrians less than an hour after it occurred. A decision to replace the system with an electric telegraph
13589-435: 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. Radiotelegraphy was also extensively used by warplanes , especially by long-range patrol planes that were sent out by 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
13716-400: Was coined by the French inventor of the semaphore telegraph , Claude Chappe , who also coined the word semaphore . A telegraph is a device for transmitting and receiving messages over long distances, i.e., for telegraphy. The word telegraph alone generally refers to an electrical telegraph . Wireless telegraphy is transmission of messages over radio with telegraphic codes. Contrary to
13843-411: Was demonstrated on the London and Birmingham Railway in July of the same year. In July 1839, a five-needle, five-wire system was installed to provide signalling over a record distance of 21 km on a section of the Great Western Railway between London Paddington station and West Drayton. However, in trying to get railway companies to take up his telegraph more widely for railway signalling , Cooke
13970-408: Was derived from a much-improved proposal by Friedrich Gerke in 1848 that became known as the "Hamburg alphabet", its only real defect being the use of an excessively long code ( ▄ ▄▄▄ ▄ ▄ ▄ and later the equal duration code ▄▄▄ ▄▄▄ ▄▄▄ ) for
14097-420: Was developed in Britain from the 1840s onward. It was used to manage railway traffic and to prevent accidents as part of the railway signalling system. On 12 June 1837 Cooke and Wheatstone were awarded a patent for an electric telegraph. This was demonstrated between Euston railway station —where Wheatstone was located—and the engine house at Camden Town—where Cooke was stationed, together with Robert Stephenson ,
14224-602: Was invented by Claude Chappe and operated in France from 1793. The two most extensive systems were Chappe's in France, with branches into neighbouring countries, and the system of Abraham Niclas Edelcrantz in Sweden. During 1790–1795, at the height of the French Revolution , France needed a swift and reliable communication system to thwart the war efforts of its enemies. In 1790, the Chappe brothers set about devising
14351-536: Was invented by US Army surgeon Albert J. Myer in the 1850s who later became the first head of the Signal Corps . Wigwag was used extensively during the American Civil War where it filled a gap left by the electrical telegraph. Although the electrical telegraph had been in use for more than a decade, the network did not yet reach everywhere and portable, ruggedized equipment suitable for military use
14478-776: Was made in 1846, but it took a decade before it was fully taken out of service. The fall of Sevastopol was reported by Chappe telegraph in 1855. The Prussian system was put into effect in the 1830s. However, they were highly dependent on good weather and daylight to work and even then could accommodate only about two words per minute. The last commercial semaphore link ceased operation in Sweden in 1880. As of 1895, France still operated coastal commercial semaphore telegraph stations, for ship-to-shore communication. The early ideas for an electric telegraph included in 1753 using electrostatic deflections of pith balls, proposals for electrochemical bubbles in acid by Campillo in 1804 and von Sömmering in 1809. The first experimental system over
14605-508: Was not immediately available. Permanent or semi-permanent stations were established during the war, some of them towers of enormous height and the system was extensive enough to be described as a communications network. A heliograph is a telegraph that transmits messages by flashing sunlight with a mirror, usually using Morse code. The idea for a telegraph of this type was first proposed as a modification of surveying equipment ( Gauss , 1821). Various uses of mirrors were made for communication in
14732-406: Was originally conceived as a system marking indentations on paper tape. A chemical telegraph making blue marks improved the speed of recording ( Bain , 1846), but was delayed by a patent challenge from Morse. The first true printing telegraph (that is printing in plain text) used a spinning wheel of types in the manner of a daisy wheel printer ( House , 1846, improved by Hughes , 1855). The system
14859-595: Was originally invented to enable the transmission of morse code by signal lamp between Royal Navy ships at sea. The heliograph was heavily used by Nelson A. Miles in Arizona and New Mexico after he took over command (1886) of the fight against Geronimo and other Apache bands in the Apache Wars . Miles had previously set up the first heliograph line in the US between Fort Keogh and Fort Custer in Montana . He used
14986-454: Was preceded by a 50-year history of ingenious but ultimately unsuccessful experiments by inventors to achieve wireless telegraphy by other means. Several wireless electrical signaling schemes based on the (sometimes erroneous) idea that electric currents could be conducted long-range through water, ground, and air were investigated for telegraphy before practical radio systems became available. The original telegraph lines used two wires between
15113-433: Was proposed by Cooke in 1842. Railway signal telegraphy did not change in essence from Cooke's initial concept for more than a century. In this system each line of railway was divided into sections or blocks of varying length. Entry to and exit from the block was to be authorised by electric telegraph and signalled by the line-side semaphore signals, so that only a single train could occupy the rails. In Cooke's original system,
15240-539: Was proved viable when the South Eastern Railway company successfully tested a three-kilometre (two-mile) gutta-percha insulated cable with telegraph messages to a ship off the coast of Folkestone . The cable to France was laid in 1850 but was almost immediately severed by a French fishing vessel. It was relaid the next year and connections to Ireland and the Low Countries soon followed. Getting
15367-445: Was quickly followed by a different system developed in the United States by Samuel Morse . The electric telegraph was slower to develop in France due to the established optical telegraph system, but an electrical telegraph was put into use with a code compatible with the Chappe optical telegraph. The Morse system was adopted as the international standard in 1865, using a modified Morse code developed in Germany in 1848. The heliograph
15494-549: Was rejected several times in favour of the more familiar, but shorter range, steam-powered pneumatic signalling. Even when his telegraph was taken up, it was considered experimental and the company backed out of a plan to finance extending the telegraph line out to Slough . However, this led to a breakthrough for the electric telegraph, as up to this point the Great Western had insisted on exclusive use and refused Cooke permission to open public telegraph offices. Cooke extended
15621-549: Was replaced by the Global Maritime Distress and 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 call before our eternal silence." In the United States the final commercial Morse code transmission was on July 12, 1999, signing off with Samuel Morse's original 1844 message, WHAT HATH GOD WROUGHT , and
15748-400: Was still used, although it was accepted that poor weather ruled it out on many days of the year. France had an extensive optical telegraph system dating from Napoleonic times and was even slower to take up electrical systems. Eventually, electrostatic telegraphs were abandoned in favour of electromagnetic systems. An early experimental system ( Schilling , 1832) led to a proposal to establish
15875-475: Was successfully tested and approved for a telegraph line between Paris and Lyon . In 1881, English inventor Shelford Bidwell constructed the scanning phototelegraph that was the first telefax machine to scan any two-dimensional original, not requiring manual plotting or drawing. Around 1900, German physicist Arthur Korn invented the Bildtelegraph widespread in continental Europe especially since
16002-617: Was the Chappe telegraph , an optical telegraph invented by Claude Chappe in the late 18th century. The system was used extensively in France, and European nations occupied by France, during the Napoleonic era . The electric telegraph started to replace the optical telegraph in the mid-19th century. It was first taken up in Britain in the form of the Cooke and Wheatstone telegraph , initially used mostly as an aid to railway signalling . This
16129-535: Was unreliable so a submarine telegraph cable was connected in 1870. Several telegraph companies were combined to form the Eastern Telegraph Company in 1872. Australia was first linked to the rest of the world in October 1872 by a submarine telegraph cable at Darwin . From the 1850s until well into the 20th century, British submarine cable systems dominated the world system. This was set out as
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