Telegraphy

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Replica of Claude Chappe's optical telegraph on the Litermont near Nalbach, Germany OptischerTelegraf.jpg
Replica of Claude Chappe's optical telegraph on the Litermont near Nalbach, Germany

Telegraphy is the long-distance transmission of textual 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 and such systems are thus not true telegraphs.

Flag semaphore Telegraphy system conveying information at a distance by means of visual signals

Flag semaphore is the telegraphy system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used in the maritime world in the 19th century. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or using lighted wands instead of flags, at night.

Pigeon post use of homing pigeons to carry messages

Pigeon post is the use of homing pigeons to carry messages. Pigeons were effective as messengers due to their natural homing abilities. The pigeons were transported to a destination in cages, where they would be attached with messages, then naturally the pigeon would fly back to its home where the owner could read their mail. They have been used in many places around the world. Pigeons have also been used to great effect in military situations, and are in this case referred to as war pigeon.

Signal varying physical quantity that conveys information

In signal processing, a signal is a function that conveys information about a phenomenon. In electronics and telecommunications, it refers to any time varying voltage, current or electromagnetic wave that carries information. A signal may also be defined as an observable change in a quantity.

Contents

The earliest true telegraph put into widespread use was the optical telegraph of Claude Chappe, invented in the late eighteenth century. The system was extensively used in France, and European countries controlled by France, during the Napoleonic era. The electric telegraph started to replace the optical telegraph in the mid-nineteenth 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 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.

Claude Chappe French inventor

Claude Chappe was a French inventor who in 1792 demonstrated a practical semaphore system that eventually spanned all of France. His system consisted of a series of towers, each within line of sight of others, each supporting a wooden mast with two crossarms on pivots that could be placed in various positions. The operator in a tower moved the arms to a sequence of positions, spelling out text messages in semaphore code. The operator in the next tower read the message through a telescope, then passed it on to the next tower. This was the first practical telecommunications system of the industrial age, and was used until the 1850s when electric telegraph systems replaced it.

Napoleonic era Wikimedia disambiguation page

The Napoleonic era is a period in the history of France and Europe. It is generally classified as including the fourth and final stage of the French Revolution, the first being the National Assembly, the second being the Legislative Assembly, and the third being the Directory. The Napoleonic era begins roughly with Napoleon Bonaparte's coup d'état, overthrowing the Directory, establishing the French Consulate, and ends during the Hundred Days and his defeat at the Battle of Waterloo. The Congress of Vienna soon set out to restore Europe to pre-French Revolution days. Napoleon brought political stability to a land torn by revolution and war. He made peace with the Roman Catholic Church and reversed the most radical religious policies of the Convention. In 1804 Napoleon promulgated the Civil Code, a revised body of civil law, which also helped stabilize French society. The Civil Code affirmed the political and legal equality of all adult men and established a merit-based society in which individuals advanced in education and employment because of talent rather than birth or social standing. The Civil Code confirmed many of the moderate revolutionary policies of the National Assembly but retracted measures passed by the more radical Convention. The code restored patriarchal authority in the family, for example, by making women and children subservient to male heads of households.

Cooke and Wheatstone telegraph

The Cooke and Wheatstone telegraph was an early electrical telegraph system dating from the 1830s invented by English inventor William Fothergill Cooke and English scientist Charles Wheatstone. It was a form of needle telegraph, and the first telegraph system to be put into commercial service. The receiver consisted of a number of needles which could be moved by electromagnetic coils to point to letters on a board. This feature was liked by early users who were unwilling to learn codes, and employers who did not want to invest in staff training.

The heliograph 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 uses 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 twentieth century. Wireless telegraphy became important for maritime use, and was a competitor to electrical telegraphy using submarine telegraph cables in international communications.

Heliograph communication device

A heliograph is a wireless telegraph that signals by flashes of sunlight reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th century. Its main uses were military, survey and forest protection work. Heliographs were standard issue in the British and Australian armies until the 1960s, and were used by the Pakistani army as late as 1975.

Apache Wars armed conflicts between indigenous peoples and white people in southwestern USA between 1849 and circa 1924

The Apache Wars were a series of armed conflicts between the United States Army and various Apache nations fought in the southwest between 1849 and 1886, though minor hostilities continued until as late as 1924. The United States inherited conflicts between American invaders and Apache groups when Mexico ceded territory after the Mexican–American War in 1846. These conflicts were continued as new United States citizens came into traditional Apache lands to raise livestock, crops and to mine minerals.

World War II 1939–1945 global war

World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 70 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.

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 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 twentieth century.

Teleprinter device for transmitting messages in written form by electrical signals

A teleprinter is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initially they were used in telegraphy, which developed in the late 1830s and 1840s as the first use of electrical engineering. The machines were adapted to provide a user interface to early mainframe computers and minicomputers, sending typed data to the computer and printing the response. Some models could also be used to create punched tape for data storage and to read back such tape for local printing or transmission.

Punched tape form of data storage

Punched tape or perforated paper tape is a form of data storage, consisting of a long strip of paper in which holes are punched to store data. Now effectively obsolete, it was widely used during much of the twentieth century for teleprinter communication, for input to computers of the 1950s and 1960s, and later as a storage medium for minicomputers and CNC machine tools.

Baudot code Pioneering five-bit character encodings

The Baudot code[bodo], invented by Émile Baudot, is a character set predating EBCDIC and ASCII. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal. The symbol rate measurement is known as baud, and is derived from the same name.

Terminology

The word "telegraph" (from Ancient Greek: τῆλε, têle , "at a distance" and γράφειν, gráphein , "to write") was first coined by the French inventor of the Semaphore telegraph, Claude Chappe, who also coined the word "semaphore". [1]

Ancient Greek Version of the Greek language used from roughly the 9th century BCE to the 6th century CE

The Ancient Greek language includes the forms of Greek used in Ancient Greece and the ancient world from around the 9th century BCE to the 6th century CE. It is often roughly divided into the Archaic period, Classical period, and Hellenistic period. It is antedated in the second millennium BCE by Mycenaean Greek and succeeded by medieval Greek.

Semaphore telegraph Communication along a chain of towers using mechanically operated paddles or shutters

A semaphore telegraph is an early system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries. Lines of relay towers with a semaphore rig at the top were built within line-of-sight of each other, at separations of 5–20 miles (8.0–32.2 km). Operators at each tower would watch the neighboring tower through a spyglass, and when the semaphore arms began to move spelling out a message, they would pass the message on to the next tower. This system was much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph, which would replace them half a century later, and would also be cheaper, faster, and more private. The line-of-sight distance between relay stations was limited by geography and weather, and prevented the optical telegraph from crossing wide expanses of water, unless a convenient island could be used for a relay station. Modern derivatives of the semaphore system include flag semaphore and the heliograph.

A "telegraph" is a device for transmitting and receiving messages over long distances, i.e., for telegraphy. The word "telegraph" alone now generally refers to an electrical telegraph. Wireless telegraphy is transmission of messages over radio with telegraphic codes.

Electrical telegraph A telegraph is a form o communication in the 1830s

An electrical telegraph was a point-to-point text messaging system, used from about the 1840s to the 1950s. It used coded pulses of electric current through dedicated wires to transmit information long distances. It was the first electrical telecommunications system, the most widely used of a number of early messaging systems called telegraphs, devised to send text messages more rapidly than written messages could be sent.

Contrary to 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 the earliest electrical telegraphs. [2]

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, [3] often shortened to a cable or a wire. 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 a diplomatic cable, is the term given to a confidential communication between a diplomatic mission and the foreign ministry of its parent country. [4] [5] These continue to be called telegrams or cables regardless of the method used for transmission.

Early signalling

Great Wall of China 20090529 Great Wall 8219.jpg
Great Wall of China

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 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 700 miles 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. [6] The Chinese signalling system extended well beyond 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. [7]

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 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 the synchronisation. [8]

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 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 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. The system would have been very slow for military purposes and there is no record of it ever being used. [8]

Optical telegraph

Schematic of a Prussian optical telegraph (or semaphore) tower, c. 1835 Construction-pruss-opt-tele.png
Schematic of a Prussian optical telegraph (or semaphore) tower, c. 1835
Demonstration of the semaphore Chappe semaphore.jpg
Demonstration of the semaphore

An optical telegraph, or semaphore telegraph 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. Early proposals for an optical telegraph system were made to the Royal Society by Robert Hooke in 1684 [9] and were first implemented on an experimental level by Sir Richard Lovell Edgeworth in 1767. [10] The first successful optical telegraph network was invented by Claude Chappe and operated in France from 1793 to 1846. [11]

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 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 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. [12]

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. [13]

Electrical telegraph

Cooke and Wheatstone's five-needle, six-wire telegraph (1837) Cooke and Wheatstone electric telegraph.jpg
Cooke and Wheatstone's five-needle, six-wire telegraph (1837)

The early ideas for an electric telegraph included in 1753 using electrostatic deflections of pith balls, [14] proposals for electrochemical bubbles in acid by Campillo in 1804 and von Sömmering in 1809. [15] [16] The first experimental system over a substantial distance was electrostatic by Ronalds in 1816. [17] Ronalds offered his invention to the British Admiralty, but it was rejected as unnecessary, [18] 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 was still used, although it was accepted that poor weather ruled it out on many days of the year. [19] :16, 37 France had an extensive optical telegraph dating from Napoleonic times and was even slower to take up electrical systems. [20] :217-218

Eventually, electrostatic telegraphs were abandoned in favour of electromagnetic systems. An early experimental system (Schilling, 1832) led to a proposal to establish a telegraph between St Petersburg and Kronstadt, but it was never completed. [21] The first electric telegraph in regular use (Gauss and Weber, 1833) connected Göttingen Observatory to the Institute of Physics about 1 km away. [22]

The first commercial telegraph was by Cooke and Wheatstone which followed their English patent of 10 June 1837 and demonstration on the London and Birmingham Railway in July. It provided signalling on a section of the Great Western Railway between London Paddington station and West Drayton in July 1839. [23] [24] However, in trying to get railway companies to take up his telegraph more widely for railway signalling, Cooke 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 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. [19] :19-20

A Morse key (c. 1900) Morsetaste.jpg
A Morse key (c. 1900)

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, the Morse system connected Baltimore to Washington, and by 1861 the west coast of the continent was connected to the east coast. [25] [26] 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. [23]

The electric telegraph quickly became a means of more general communication. The Morse system was officially adopted as the standard for continental European telegraphy in 1851 with a revised code, which later became the basis of International Morse Code. [27] However, Great Britain and the British Empire continued to use the Cooke and Wheatstone system, in some places as late as the 1930s. [23] Likewise, the United States continued to use American Morse code internally, requiring translation operators skilled in both codes for international messages. [27]

Railway telegraphy

An early Cooke and Wheatstone double-needle railway telegraph instrument at the National Railway Museum GWR Cooke and Wheatstone double needle telegraph instrument.jpg
An early Cooke and Wheatstone double-needle railway telegraph instrument at the National Railway Museum
A block signalling instrument as used in Britain in the 20th century Block instrument.jpg
A block signalling instrument as used in Britain in the 20th century

Railway signal telegraphy 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 June 12, 1837 Cooke and Wheatstone were awarded a patent for an electric telegraph. [28] 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, 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 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 several miles 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, 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. [29]

Heliograph

Australian troops using a Mance mk.V heliograph in the Western Desert in November 1940 Australian Heliograph in Egyptian Desert 1940.png
Australian troops using a Mance mk.V heliograph in the Western Desert in November 1940
US Forest Service lookout using a Colomb shutter type heliograph in 1912 at the end of a telephone line 11903A LO with Heliograph CA 1912 (22762702845).jpg
US Forest Service lookout using a Colomb shutter type heliograph in 1912 at the end of a telephone line

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 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, a morse key was added to the apparatus to give the operator the same degree of control as in the electric telegraph. [30]

Another type of heliograph was the heliostat 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) was originally invented to enable the transmission of morse code by signal lamp between Royal Navy ships at sea. [30]

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 the heliograph to fill in vast, thinly populated areas that were not covered by the electric telegraph. Twenty-six stations covered an area 200 by 300 miles. In a test of the system, a message was relayed 400 miles in four hours. Miles' enemies used smoke signals and flashes of sunlight from metal, but lacked a sophisticated telegraph code. [31] The heliograph was ideal for use in 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. [30]

Use of the heliograph declined from 1915 onwards, but remained in service in Britain and British Commonwealth countries for some time. Australian forces used 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). [30]

Teleprinter

A Baudot keyboard, 1884 Clavier Baudot.jpg
A Baudot keyboard, 1884
A Creed Model 7 teleprinter, 1931 Bundesarchiv Bild 183-2008-0516-500, Fernschreibmaschine mit Telefonanschluss.jpg
A Creed Model 7 teleprinter, 1931

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. [32] The Morse telegraph (1837) 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 retarded 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 was adopted by Western Union. [33] 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 a code of the same length making it more machine friendly. [34] The Baudot code was used on the earliest ticker tape machines (Calahan, 1867), a system for mass distributing stock price information. [35]

Automated punched-tape transmission

Creed paper tape reader at The National Museum of Computing Creed model 6S-2 paper tape reader.jpg
Creed paper tape reader at The National Museum of Computing

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 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 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. [36]

The first widely used system (Wheatstone, 1858) was first put into service with the British General Post Office in 1867. A novel feature of the Wheatstone system was the use of bipolar encoding. That is, both positive and negative polarity voltages were used. [37] Bipolar encoding has several advantages, one of which is that it permits duplex communication. [38] The Wheatstone tape reader was capable of a speed of 400 words per minute. [39] :190

Oceanic telegraph cables

The first message is received by the Submarine Telegraph Company in London from Paris on the Foy-Breguet instrument in 1851. The equipment in the background is a Cooke and Wheatstone set for onward transmission. Submarine Cornhill 1852.jpg
The first message is received by the Submarine Telegraph Company in London from Paris on the Foy-Breguet instrument in 1851. The equipment in the background is a Cooke and Wheatstone set for onward transmission.
The Eastern Telegraph Company network in 1901 1901 Eastern Telegraph cables.png
The Eastern Telegraph Company network in 1901

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, a good insulator that was both flexible and capable of resisting the ingress of seawater was required, and at first this was not available. 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 was proved viable when the South Eastern Railway company successfully tested a two-mile gutta-percha insulated cable with telegraph messages to a ship off the coast of Folkstone. [40] The cable to France was laid in 1850 but was almost immediately severed by a French fishing vessel. [41] It was relaid the next year [41] and connections to Ireland and the Low Countries soon followed.

Getting 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 before being destroyed by applying too high a voltage. The slow speed of transmission of this cable (sometimes all day to send a message) prompted Lord Kelvin and Oliver Heaviside to find better mathematical descriptions of long transmission lines. The company finally succeeded in 1866 with the ship SS Great Eastern and an improved cable construction. [42]

An overland telegraph from Britain to India was first connected in 1866 but was unreliable so a submarine telegraph cable was connected in 1870. [43] 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. [44]

From the 1850s until well into the 20th century, British submarine cable systems dominated the world system. This was set out as a formal strategic goal, which became known as the All Red Line. [45] 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. [46] During World War I, Britain's telegraph communications were almost completely uninterrupted while it was able to quickly cut Germany's cables worldwide. [45]

Facsimile

Alexander Bain's facsimile machine, 1850 Bain improved facsimile 1850.png
Alexander Bain's facsimile machine, 1850

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 abbot, Giovanni Caselli, also created an electric telegraph that could transmit images. Caselli called his invention "Pantelegraph". Pantelegraph was successfully tested and approved for a telegraph line between Paris and Lyon. [47] [48]

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 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.

Wireless telegraphy

Marconi watching associates raising the kite (a "Levitor" by B.F.S. Baden-Powell ) used to lift the antenna at St. John's, Newfoundland, December 1901 Marconi at newfoundland.jpg
Marconi watching associates raising the kite (a "Levitor" by B.F.S. Baden-Powell ) used to lift the antenna at St. John's, Newfoundland, December 1901
Post Office Engineers inspect Marconi's equipment on Flat Holm, May 1897 Post Office Engineers.jpg
Post Office Engineers inspect Marconi's equipment on Flat Holm, May 1897

The late 1880s through to the 1890s saw 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 the general consensus was that these new waves (similar to light) would be just as short range as light, and, therefore, useless for long range communication. [50]

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. [51] Building on 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 the transmitter and receiver, Marconi was able, by early 1896, to transmit radio far beyond the short ranges that had been predicted. [52] 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 the British government followed—by March 1897, Marconi had transmitted Morse code signals over a distance of about 6 kilometres (3.7 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. [53] The message sent was "ARE YOU READY". From his Fraserburgh base, he transmitted the first long-distance, cross-country wireless signal to Poldhu in Cornwall.[ when? ][ citation needed ] His star rising, he was soon sending signals across The English channel (1899), from shore to ship (1899) and finally across the Atlantic (1901). [54] 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. [55]

Radiotelegraphy proved effective for rescue work in sea disasters by enabling effective communication between ships and from ship to shore. In 1904, Marconi began 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. [56] [57] Notably, Marconi's apparatus was used to help rescue efforts after the sinking of 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."

Telegram services

Western Union telegram circa 1930 1930 Western Union telegram Millsaps College Mississippi State University.jpg
Western Union telegram circa 1930
Example of a modern telegram (2010) Sample telegram to United States, 2010.jpg
Example of a modern telegram (2010)

A telegram service is a company or public entity that delivers telegraphed messages. [35]

Historically, telegrams were sent between a network of interconnected telegraph offices. A person visiting a local telegraph office paid by the word to have a message telegraphed to another office and delivered to the addressee on a paper form. [58] :276 Messages sent by telegraph could be delivered faster than mail, and even in the telephone age, the telegram remained popular for social and business correspondence. At their peak in 1929, an estimated 20 million telegrams were sent. [58] :274

Telegram services still operate in much of the world (see worldwide use of telegrams by country), but e-mail and text messaging have rendered telegrams obsolete in many countries, and the number of telegrams sent annually has been declining rapidly since the 1980s. [59] Where telegram services still exist, the transmission method between offices is no longer by telegraph, but by telex or IP link. [60]

Telegram length

As telegrams have been traditionally charged by the word, messages were often abbreviated to pack information into the smallest possible number of words, in what came to be called "telegram style".

The average length of a telegram in the 1900s in the US was 11.93 words; more than half of the messages were 10 words or fewer. [61] According to another study, the mean length of the telegrams sent in the UK before 1950 was 14.6 words or 78.8 characters. [62] For German telegrams, the mean length is 11.5 words or 72.4 characters. [62] At the end of the 19th century, the average length of a German telegram was calculated as 14.2 words. [62]

Telex

Teletype 32 terminal with telex dial-up facility Telex machine ASR-32.jpg
Teletype 32 terminal with telex dial-up facility

Telex (TELegraph EXchange) was a public switched network of teleprinters. It used rotary-telephone-style pulse dialling for automatic routing through the network. It initially used the Baudot code for messages. Telex development began in Germany in 1926, becoming an operational service in 1933 run by the Reichspost (Reich postal service). It had a speed of 50 baud—approximately 66 words per minute. Up to 25 telex channels could share a single long-distance telephone channel by using voice frequency telegraphy multiplexing, making telex the least expensive method of reliable long-distance communication.[ citation needed ] Telex was introduced into Canada in July 1957, and the United States in 1958. [63] A new code, ASCII, was introduced in 1963 by the American Standards Association. ASCII was a 7-bit code and could thus support a larger number of characters than Baudot. In particular, ASCII supported upper and lower case whereas Baudot was upper case only.

Decline

Telegraph use began to permanently decline around 1920. [19] :248 The decline began with the growth of the use of the telephone. [19] :253 Ironically, the invention of the telephone grew out of the development of the harmonic telegraph, a device which was supposed to increase the efficiency of telegraph transmission and improve the profits of telegraph companies. Western Union gave up their patent battle with Alexander Graham Bell because they believed the telephone was not a threat to their telegraph business. The Bell Telephone Company was formed in 1877 and had 230 subscribers which grew to 30,000 by 1880. By 1886 there were a quarter of a million phones worldwide, [58] :276-277 and nearly 2 million by 1900. [39] :204 The decline was briefly postponed by the rise of special occasion congratulatory telegrams. Traffic continued to grow between 1867 and 1893 despite the introduction of the telephone in this period, [58] :274 but by 1900 the telegraph was definitely in decline. [58] :277

There was a brief resurgence in telegraphy during World War I but the decline continued as the world entered the Great Depression years of the 1930s. [58] :277 Telegraph lines continued to be an important means of distributing news feeds from news agencies by teleprinter machine until the rise of the internet in the 1990s. For Western Union, one service remained highly profitable—the wire transfer of money. This service kept Western Union in business long after the telegraph had ceased to be important. [58] :277

Social implications

The telegraph freed communication from the time constraints of postal mail and revolutionized the global economy and society. [64] [65] By the end of the 19th century, the telegraph was becoming an increasingly common medium of communication for ordinary people. The telegraph isolated the message (information) from the physical movement of objects or the process. [66]

There was some fear of the new technology. According to author Allan J. Kimmel, some people "feared that the telegraph would erode the quality of public discourse through the transmission of irrelevant, context-free information." Henry David Thoreau thought of the Transatlantic cable "...perchance the first news that will leak through into the broad flapping American ear will be that Princess Adelaide has the whooping cough." Kimmel says these fears anticipate many of the characteristics of the modern internet age. [67]

Initially, the telegraph was expensive to use, so was mostly limited to businesses that could use it to improve profits. The telegraph had an enormous effect on three industries; finance, newspapers, and railways. Telegraphy facilitated the growth of organizations "in the railroads, consolidated financial and commodity markets, and reduced information costs within and between firms". [65] In the US, there were 200 to 300 stock exchanges before the telegraph, but most of these were unnecessary and unprofitable once the telegraph made financial transactions at a distance easy and drove down transaction costs. [58] :274-275 This immense growth in the business sectors influenced society to embrace the use of telegrams once the cost had fallen.

Worldwide telegraphy changed the gathering of information for news reporting. Journalists were using the telegraph for war reporting as early as 1846 when the Mexican–American War broke out. News agencies were formed, such as Associated Press, for the purpose of reporting news by telegraph. [58] :274-275 Messages and information would now travel far and wide, and the telegraph demanded a language "stripped of the local, the regional; and colloquial", to better facilitate a worldwide media language. [66] Media language had to be standardized, which led to the gradual disappearance of different forms of speech and styles of journalism and storytelling.

The spread of the railways created a need for an accurate standard time to replace local arbitrary standards based on local noon. The means of achieving this synchronisation was the telegraph. This emphasis on precise time has led to major societal changes such as the concept of the time value of money. [58] :273-274

The shortage of men to work as telegraph operators in the American Civil War opened up the opportunity for women of a well-paid skilled job. [58] :274

The economic impact of the telegraph was not much studied by economic historians until parallels started to be drawn with the rise of the internet. In fact, the electric telegraph was as important as the invention of printing in this respect. According to economist Ronnie J. Phillips, the reason for this may be that institutional economists paid more attention to advances that required greater capital investment. The investment required to build railways, for instance, is orders of magnitude greater than that for the telegraph. [58] :269-270

Newspaper names

Numerous newspapers and news outlets in various countries, such as The Daily Telegraph in Britain, The Telegraph in India, De Telegraaf in the Netherlands, and the Jewish Telegraphic Agency in the US, were given names which include the word "telegraph" due to their having received news by means of electric telegraphy. Some of these names are retained even though different means of news acquisition are now used.

See also

Related Research Articles

Émile Baudot French engineer

Jean-Maurice-Émile Baudot, French telegraph engineer and inventor of the first means of digital communication Baudot code, was one of the pioneers of telecommunications. He invented a multiplexed printing telegraph system that used his code and allowed multiple transmissions over a single line. The baud unit was named after him.

Guglielmo Marconi Italian inventor and radio pioneer

Guglielmo Marconi, 1st Marquis of Marconi was an Italian inventor, and electrical engineer, known for his pioneering work on long-distance radio transmission, development of Marconi's law, and a radio telegraph system. He is credited as the inventor of radio, and he shared the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy".

Morse code Transmission of language with brief pulses

Morse code is a character encoding scheme used in telecommunication that encodes text characters as standardized sequences of two different signal durations called dots and dashes or dits and dahs. Morse code is named for Samuel F. B. Morse, an inventor of the telegraph.

Wireless telegraphy

Wireless telegraphy means transmission of telegraph signals by radio waves; a more specific term for this is radiotelegraphy. Before about 1910 when radio became dominant, the term wireless telegraphy was also used for various other experimental technologies for transmitting telegraph signals without wires, such as electromagnetic induction, and ground conduction telegraph systems.

Optical communication communication at a distance using light to carry information

Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880.

Asynchronous serial communication is a form of serial communication in which the communicating endpoints' interfaces are not continuously synchronized by a common clock signal. Instead of a common synchronization signal, the data stream contains synchronization information in form of start and stop signals, before and after each unit of transmission, respectively. The start signal prepares the receiver for arrival of data and the stop signal resets its state to enable triggering of a new sequence.

A telegraph code is one of the character encodings used to transmit information through telegraphy machines. The most famous such code is Morse code.

A secret broadcast is, simply put, a broadcast that is not for the consumption of the general public. The invention of the wireless was initially greeted as a boon by armies and navies. Units could now be coordinated by nearly instant communications. An adversary could glean valuable and sometimes decisive intelligence from intercepted radio signals:

American Morse code Morse code variant used on landline telegraph systems in the U.S.

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 because, after most of the rest of the world adopted "International Morse Code," the companies that continued to use the original Morse Code were mainly located in the United States. American Morse is now nearly extinct—it is most frequently seen in American railroad museums and American Civil War reenactments—and "Morse Code" today virtually always means the International Morse which supplanted American Morse.

History of telecommunication aspect of history relating to telecommunications

The history of telecommunication began with the use of smoke signals and drums in Africa, the Americas and parts of Asia. In the 1790s, the first fixed semaphore systems emerged in Europe; however it was not until the 1830s that electrical telecommunication systems started to appear. This article details the history of telecommunication and the individuals who helped make telecommunication systems what they are today. The history of telecommunication is an important part of the larger history of communication.

Invention of radio aspect of history relating to the invention of radio

The invention of radio communication, although generally attributed to Guglielmo Marconi in the 1890s, spanned many decades, from theoretical underpinnings, through proof of the phenomenon's existence, development of technical means, to its final use in signalling.

Procedure signs or prosigns are shorthand signals used in radio telegraphy procedures, for the purpose of simplifying and standardizing communications related to radio operating issues among two or more radio operators. They are distinct from general Morse code abbreviations, which consist mainly of brevity codes that convey messages to other parties with greater speed and accuracy.

History of telegraphy in Australia aspect of history relating to telegraphy in Australia

Australia was a relatively early adopter of telegraph technology in the middle nineteenth century, despite its low population densities and the difficult conditions sometimes encountered in laying lines. From 1858 onwards, the major capitals were progressively linked, culminating in the addition of Perth in 1877. Australia was linked to the rest of the world for the first time in 1872, through the Overland Telegraph which ran some 3200 km from Adelaide through to Darwin. The network continued to expand in size and sophistication until 1959 and in heavy usage until 1945, after which time telephone usage began to erode public patronage of telegraphy services. The final publicly provided telegraphy service was closed in 1993.

Telex switched network of teleprinters

The telex network was a public switched network of teleprinters similar to a telephone network, for the purposes of sending text-based messages. Telex was a major method of sending written messages electronically between businesses in the post-World War II period. Its usage went into decline as the fax machine grew in popularity in the 1980s.

Donald Murray (1865–1945) was an electrical engineer and the inventor of a telegraphic typewriter system using an extended Baudot code that was a direct ancestor of the teleprinter. He can justifiably be called the "Father of the remote Typewriter".

Women in telegraphy The history of womens involvement in telegraphy

Women in telegraphy have been evident since the 1840s. The introduction of practical systems of telegraphy in the 1840s led to the creation of a new occupational category, the telegrapher, telegraphist or telegraph operator. Duties of the telegrapher included sending and receiving telegraphic messages, known as telegrams, using a variety of signaling systems, and routing of trains for the railroads. While telegraphy is often viewed as a males-only occupation, women were also employed as telegraph operators from its earliest days. Telegraphy was one of the first communications technology occupations open to women.

Electrical telegraphy in the United Kingdom History of electrical telegraphy in the United Kingdom

Electrical telegraphy in the United Kingdom led the world in the first half of the nineteenth century. Electrical telegraphy is telegraphy over conducting wires. It is distinct from the optical telegraphy that preceded it and the radiotelegraphy that followed it. Francis Ronalds first demonstrated a working telegraph over a substantial distance in 1816, but was unable to put it into use. William Fothergill Cooke, starting in 1836, developed the first commercial telegraph put into operation with the scientific assistance of Charles Wheatstone, the battery invented by John Frederic Daniell, and the relay invented by Edward Davy.

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Further reading

Technology

  • Armagnay, Henri (1908). "Phototelegraphy". Annual Report of the Board of Regents of the Smithsonian Institution: 197–207. Retrieved 2009-08-07.
  • Dargan, J. "The Railway Telegraph", Australian Railway Historical Society Bulletin, March, 1985 pp. 49–71
  • Gray, Thomas (1892). "The Inventors Of The Telegraph And Telephone". Annual Report of the Board of Regents of the Smithsonian Institution: 639–659. Retrieved 2009-08-07.
  • Pichler, Franz, Magneto-Electric Dial Telegraphs: Contributions of Wheatstone, Stoehrer and Siemens, The AWA Review vol. 26, (2013).
  • Ross, Nelson E. HOW TO WRITE TELEGRAMS PROPERLY The Telegraph Office (1928)
  • Wheen, Andrew;— DOT-DASH TO DOT.COM: How Modern Telecommunications Evolved from the Telegraph to the Internet (Springer, 2011) ISBN   978-1-4419-6759-6
  • Wilson, Geoffrey, The Old Telegraphs, Phillimore & Co Ltd 1976 ISBN   0-900592-79-6; a comprehensive history of the shutter, semaphore and other kinds of visual mechanical telegraphs.