Editing Telegraphy (section)

== History ==

=== Early signalling ===

[[File:20090529 Great Wall 8219.jpg|thumb|A section of the [[Great Wall of China]] built during the [[Ming dynasty]] (1368–1644)]]

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]]. By 400&nbsp;BC, signals could be sent by [[beacon|beacon fires]] or [[military drum|drum beats]], and by 200&nbsp;BC complex flag signalling had developed. During the [[Han dynasty]] (202&nbsp;BC{{snd}}220&nbsp;AD), signallers mainly used flags and wood fires—via the light of the flames swung high into the air at night, and via dark smoke produced by the addition of wolf dung during the day—to send signals.<ref>{{Cite book |last=Turnbull |first=Stephen |title=The Great Wall of China 221 BC–AD 1644 |publisher=Osprey |location=Oxford |year=2007 |isbn=978-1-84603-004-8 |page=37}}</ref> By the [[Tang dynasty]] (618–907) a message could be sent {{convert|700|mi|km|order=flip}} in 24 hours. The [[Ming dynasty]] (1368–1644) used [[artillery]] as another possible signalling method. While the signalling was complex (for instance, flags of different colours could be used to indicate enemy strength), only predetermined messages could be sent.<ref>Christopher H. Sterling, "Great Wall of China", pp. 197–198 in, Christopher H. Sterling (ed), ''Military Communications: From Ancient Times to the 21st Century'', ABC-CLIO, 2008 {{ISBN|1851097325}}.</ref> 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]].<ref>Morris Rossabi, ''From Yuan to Modern China and Mongolia'', p. 203, Brill, 2014 {{ISBN|9004285296}}.</ref>

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 [[torch]]es indicated when to start and stop draining to keep the synchronisation.<ref name=Woods>David L. Woods, "Ancient signals", pp. 24–25 in, Christopher H. Sterling (ed), ''Military Communications: From Ancient Times to the 21st Century'', ABC-CLIO, 2008 {{ISBN|1851097325}}.</ref>

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 league|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. 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 the [[First Macedonian War]]. Nothing else that could be described as a true telegraph existed until the 17th century.<ref name=Woods/><ref name=Holzmann/>{{rp|26–29}} 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.<ref name=Holzmann/>{{rp|32–34}}

=== Optical telegraph ===

[[File:Construction-pruss-opt-tele.png|thumb|upright=0.7|right|Schematic of a Prussian optical telegraph (or [[Optical telegraph|semaphore]]) tower, {{Circa|1835}}]]
[[File:Chappe semaphore.jpg|thumb|upright|left|19th-century demonstration of the semaphore]]
{{main|Optical telegraph}}

An [[optical 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. 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<ref>{{cite web|url=http://mysite.du.edu/~jcalvert/railway/semaphor/semhist.htm |title=The Origin of the Railway Semaphore |publisher=Mysite.du.edu |access-date=17 June 2013}}</ref> and were first implemented on an experimental level by Sir [[Richard Lovell Edgeworth]] in 1767.<ref>{{cite book |url=https://books.google.com/books?id=9eLCsHfKq1IC|title=Communications: An International History of the Formative Years |author=Burns, Francis W. |year=2004 |publisher=IET |isbn=978-0-86341-330-8}}</ref> The first successful optical telegraph network was invented by [[Claude Chappe]] and operated in France from 1793.<ref>{{Cite web|url=https://www.britannica.com/technology/semaphore|title=Semaphore &#124; communications|website=Encyclopedia Britannica}}</ref> The two most extensive systems were Chappe's in France, with branches into neighbouring countries, and the system of [[Abraham Niclas Edelcrantz]] in Sweden.<ref name=Holzmann>Gerard J. Holzmann; Björn Pehrson, ''The Early History of Data Networks'', IEEE Computer Society Press, 1995 {{isbn|0818667826}}.</ref>{{rp|ix–x, 47}}

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 {{convert|16|km|mi|frac=2}}. 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 {{convert|230|km|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.<ref>[https://www.bbc.co.uk/news/magazine-22909590 How Napoleon's semaphore telegraph changed the world] {{Webarchive|url=https://web.archive.org/web/20190824001923/https://www.bbc.co.uk/news/magazine-22909590 |date=24 August 2019 }}, BBC News, Hugh Schofield, 16 June 2013</ref> A decision to replace the system with an electric telegraph was made in 1846, but it took a decade before it was fully taken out of service. The [[Siege of Sevastopol (1854–1855)|fall of Sevastopol]] was reported by Chappe telegraph in 1855.<ref name=Holzmann/>{{rp|92–94}}

The [[Prussian semaphore system|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.<ref>"A Semaphore Telegraph Station", ''Scientific American Supplement'', 20 April 1895, page 16087.</ref>
{{clear|left}}

=== Electrical telegraph ===

{{Main|Electrical telegraph}}
{{See also|Electrical telegraphy in the United Kingdom}}
[[File:Cooke and Wheatstone electric telegraph.jpg|thumb|left|upright|[[Cooke and Wheatstone telegraph|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,<ref>E. A. Marland, ''Early Electrical Communication'', Abelard-Schuman Ltd, London 1964, no ISBN, Library of Congress 64-20875, pages 17–19;</ref> proposals for [[electrochemical]] bubbles in acid by [[Francisco Salva Campillo|Campillo]] in 1804 and [[Samuel Thomas von Sömmering|von Sömmering]] in 1809.<ref>Jones, R. Victor [http://people.seas.harvard.edu/~jones/cscie129/images/history/von_Soem.html Samuel Thomas von Sömmering's "Space Multiplexed" Electrochemical Telegraph (1808–10)] {{Webarchive|url=https://web.archive.org/web/20121011042334/http://people.seas.harvard.edu/~jones/cscie129/images/history/von_Soem.html |date=11 October 2012 }}, Harvard University website. Attributed to "[https://books.google.com/books?id=Oxc7AAAAMAAJ Semaphore to Satellite]", International Telecommunication Union, Geneva 1965.</ref><ref>{{Citation |last= Fahie |first= J. J. |title= A History of Electric Telegraphy to the year 1837 |place= London |publisher= E. & F. N. Spon |year= 1884 |url= https://www.princeton.edu/ssp/joseph-henry-project/telegraph/A_history_of_electric_telegraphy_to_the.pdf}}</ref> The first experimental system over a substantial distance was by [[Francis Ronalds|Ronalds]] in 1816 using an [[electrostatic generator]]. Ronalds offered his invention to the [[British Admiralty]], but it was rejected as unnecessary,<ref>{{Cite journal|last=Ronalds|first=B.F.|date=2016|title=Sir Francis Ronalds and the Electric Telegraph|journal=International Journal for the History of Engineering & Technology|volume=86|pages=42–55|doi=10.1080/17581206.2015.1119481|s2cid=113256632}}</ref> 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.<ref name=Kieve/>{{rp|16, 37}} France had an extensive optical telegraph system dating from Napoleonic times and was even slower to take up electrical systems.<ref>Jay Clayton, "The voice in the machine", ch. 8 in, Jeffrey Masten, Peter Stallybrass, Nancy J. Vickers (eds), ''Language Machines: Technologies of Literary and Cultural Production'', Routledge, 2016 {{ISBN|9781317721826}}.</ref>{{rp|217–218}}

Eventually, electrostatic telegraphs were abandoned in favour of [[electromagnet]]ic systems. An early experimental system ([[Pavel Schilling|Schilling]], 1832) led to a proposal to establish a telegraph between [[St Petersburg]] and [[Kronstadt]], but it was never completed.<ref>{{cite web |url=http://www.ieeeghn.org/wiki/index.php/Milestones:Shilling%27s_Pioneering_Contribution_to_Practical_Telegraphy,_1828-1837 |title=Milestones:Shilling's Pioneering Contribution to Practical Telegraphy, 1828–1837 |work=IEEE Global History Network |publisher=IEEE |access-date=26 July 2011}}</ref> The first operative electric telegraph ([[Carl Friedrich Gauss|Gauss]] and [[Wilhelm Eduard Weber|Weber]], 1833) connected [[Göttingen Observatory]] to the Institute of Physics about 1&nbsp;km away during experimental investigations of the geomagnetic field.<ref>R. W. Pohl, Einführung in die Physik, Vol. 3, Göttingen (Springer) 1924</ref>

The first commercial telegraph was by [[William Fothergill Cooke|Cooke]] and [[Charles Wheatstone|Wheatstone]] following their English patent of 10 June 1837. It was demonstrated on the [[London and Birmingham Railway]] in July of the same year.<ref name="guarnieri1">{{Cite journal|last=Guarnieri|first=M.|year=2019|title= Messaging Before the Internet—Early Electrical Telegraphs |journal= IEEE Industrial Electronics Magazine|volume=13|issue=1|pages=38–41+53|doi=10.1109/MIE.2019.2893466|hdl=11577/3301045 |s2cid=85499543|hdl-access=free}}</ref> In July 1839, a five-needle, five-wire system was installed to provide signalling over a record distance of 21&nbsp;km on a section of the [[Great Western Railway]] between [[London Paddington station]] and West Drayton.<ref name="Huurdeman">Anton A. Huurdeman, ''The Worldwide History of Telecommunications'' (2003) pp. 67–69</ref><ref>{{Citation |last= Roberts |first= Steven |author-link= Stephen Roberts (historian) |title= Distant Writing|url= http://distantwriting.co.uk/index.htm }}</ref> 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.<ref name=Kieve/>{{rp|19–20}}

[[File:Morsetaste.jpg|thumb|upright=0.9|A [[Telegraph key|Morse key]] ({{Circa|1900}})]]

Most of the early electrical systems required multiple wires (Ronalds' system was an exception), but the system developed in the United States by [[Samuel Morse|Morse]] and [[Alfred Vail|Vail]] was a single-wire system. This was the system that first used the soon-to-become-ubiquitous [[Morse code]].<ref name="guarnieri1"/> By 1844, the Morse system connected [[Baltimore-Washington telegraph line|Baltimore to Washington]], and by 1861 the west coast of the continent was connected to the east coast.<ref>{{Cite book|title=Dictionary of Media and Communication Studies|last1=Watson|first1=J.|last2=Hill|first2=A.|publisher=Bloomsbury|year=2015|edition= 9th|location=London, UK|via= Credo Reference}}</ref><ref>{{Cite web |url=http://www.americaslibrary.gov/jb/civil/jb_civil_telegrap_1.html|title= The First Transcontinental Telegraph System Was Completed October 24, 1861|website=America's Library|access-date= 29 April 2019}}</ref> 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 telegraph|needle displays]].<ref name="Huurdeman"/>

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]].<ref name=Coe>Lewis Coe, ''The Telegraph: A History of Morse's Invention and Its Predecessors in the United States'', McFarland, p. 69, 2003 {{ISBN|0-78641808-7}}.</ref> However, Great Britain and the [[British Empire]] continued to use the Cooke and Wheatstone system, in some places as late as the 1930s.<ref name="Huurdeman"/> Likewise, the United States continued to use [[American Morse code]] internally, requiring translation operators skilled in both codes for international messages.<ref name=Coe/>
{{clear}}

=== Railway telegraphy ===

[[File:GWR Cooke and Wheatstone double needle telegraph instrument.jpg|thumb|left|An early Cooke and Wheatstone double-needle railway telegraph instrument at the [[National Railway Museum]]]] 
[[File:Block instrument.jpg|thumb|right|A block signalling instrument as used in Britain in the 20th century]]

{{See also|Railway signalling}}
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 12 June 1837 Cooke and Wheatstone were awarded a patent for an electric telegraph.<ref>{{Citation |title= How the UK's railways shaped the development of the telegraph |publisher= British Telecom |url= http://home.bt.com/tech-gadgets/history-of-communication-uk-railways-telegraph-patent-cooke-wheatstone-11364186628315 }}</ref> 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|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 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, a single-needle telegraph was adapted to indicate just two messages: "Line Clear" and "Line Blocked". The [[Signalman (rail)|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.<ref>{{Citation |last= Roberts |first= Steven |author-link= Stephen Roberts (historian) |title= Distant Writing: 15. Railway Signal Telegraphy 1838 – 1868 |url= http://distantwriting.co.uk/railwaysignaltelegaphy.html }}</ref>
{{clear|left}}

=== Wigwag ===

{{main|Wigwag (flag signals)}}
Wigwag is a form of [[flag signals|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 {{convert|20|mi|km|order=flip|abbr=on}} 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 was invented by US Army surgeon [[Albert J. Myer]] in the 1850s who later became the first head of the [[Signal Corps (United States Army)|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 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.<ref>Rebecca Raines, [https://history.army.mil/html/books/030/30-17-1/CMH_Pub_30-17-1.pdf ''Getting the Message Through''] {{Webarchive|url=https://web.archive.org/web/20191026142001/https://history.army.mil/html/books/030/30-17-1/CMH_Pub_30-17-1.pdf |date=26 October 2019 }}, US Government Printing Office, 1996 {{isbn|0160872812}}.</ref><ref>Albert J. Myer, [https://hdl.handle.net/2027/nyp.33433009343363 ''A Manual of Signals''], D. Van Nostrand, 1866, {{oclc|680380148}}.</ref>

=== Heliograph ===

[[File:Australian Heliograph in Egyptian Desert 1940.png|thumb|right|upright=0.7|Australian troops using a Mance mk.V heliograph in the [[Western Desert (Egypt)|Western Desert]] in November 1940]]
{{main|Heliograph}}
[[File:11903A LO with Heliograph CA 1912 (22762702845).jpg|thumb|left|upright=1.2|[[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 ([[Carl Friedrich Gauss|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 ([[Henry Christopher Mance|Mance]], 1869). The system was used by the French during the [[Siege of Paris (1870–71)|1870–71 siege of Paris]], with night-time signalling using [[kerosene lamp]]s 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.<ref name=Woods2>David L. Woods, "Heliograph and mirrors", pp. 208–211 in, Christopher H. Sterling (ed), ''Military Communications: From Ancient Times to the 21st Century'', ABC-CLIO, 2008 {{ISBN|1851097325}}.</ref>

Another type of heliograph was the [[heliostat]] or [[heliotrope (instrument)|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 ([[Francis Bolton|Bolton]] and [[Philip Howard Colomb|Colomb]], 1862) was originally invented to enable the transmission of morse code by [[signal lamp]] between [[Royal Navy]] ships at sea.<ref name=Woods2/>

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 (Montana)|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 {{convert|200 by 300|mi|km|order=flip|abbr=on}}. In a test of the system, a message was relayed {{convert|400|mi|km|order=flip|abbr=on}} in four hours. Miles' enemies used [[smoke signal]]s and flashes of sunlight from metal, but lacked a sophisticated telegraph code.<ref>Nelson A. Miles, ''Personal Recollections and Observations of General Nelson A. Miles'', vol. 2, pp. 481–484, University of Nebraska Press, 1992 {{ISBN|0803281811}}.</ref> 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.<ref name=Woods2/>

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).<ref name=Woods2/>
{{clear|left}}

=== Teleprinter ===

{{main article|Teleprinter}}
[[File:Clavier Baudot.jpg|thumb|left|upright=0.9|A Baudot keyboard, 1884]]
[[File:Bundesarchiv Bild 183-2008-0516-500, Fernschreibmaschine mit Telefonanschluss.jpg|thumb|right|upright=1.3|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.<ref name="query.nytimes.com">{{Citation| title = Typewriter May Soon Be Transmitter of Telegrams| newspaper = [[The New York Times]] | date = 25 January 1914| url = https://timesmachine.nytimes.com/timesmachine/1914/01/25/100081424.pdf}}</ref> 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 ([[Alexander Bain (inventor)|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 [[Sort (typesetting)|types]] in the manner of a [[Daisy wheel printing|daisy wheel printer]] ([[Royal Earl House|House]], 1846, improved by [[David Edward Hughes|Hughes]], 1855). The system was adopted by [[Western Union]].<ref>{{cite web|url=http://people.clarkson.edu/~ekatz/scientists/hughes.html|title=David Edward Hughes|date=14 April 2007|publisher=Clarkson University|archive-url=https://web.archive.org/web/20080422072443/http://people.clarkson.edu/~ekatz/scientists/hughes.html|archive-date=22 April 2008}}</ref>

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 ([[Émile Baudot|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.<ref name=Beauchamp>{{cite book |last = Beauchamp |first = K.G. |title = History of Telegraphy: Its Technology and Application |publisher = [[Institution of Engineering and Technology|IET]] |year = 2001 |pages = 394–395 |isbn = 978-0-85296-792-8}}</ref> The Baudot code was used on the earliest [[ticker tape]] machines ([[Edward A. Calahan|Calahan]], 1867), a system for mass distributing information on current price of publicly listed companies.<ref name=Smith433>Richard E. Smith, ''Elementary Information Security'', p. 433, Jones & Bartlett Publishers, 2015 {{ISBN|1284055949}}.</ref>
{{clear}}

=== Automated punched-tape transmission ===

[[File:Creed model 6S-2 paper tape reader.jpg|thumb|upright=1.4|Creed paper tape reader at [[The National Museum of Computing]] on [[Bletchley Park]]]]

{{See also|Punched tape}}
In a [[Punched tape|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.<ref>Anton A. Huurdeman, ''The Worldwide History of Telecommunications'', p. 72, Wiley, 2003 {{ISBN|0471205052}}.</ref>

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.<ref>Ken Beauchamp, ''History of Technology'', p. 87, Institution of Engineering and Technology, 2001 {{ISBN|0852967926}}.</ref> Bipolar encoding has several advantages, one of which is that it permits [[Duplex (telecommunications)|duplex]] communication.<ref>Lewis Coe, ''The Telegraph: A History of Morse's Invention and Its Predecessors in the United States'', pp. 16–17, McFarland, 2003 {{ISBN|0786418087}}.</ref> The Wheatstone tape reader was capable of a speed of 400 words per minute.<ref name="Standage">Tom Standage, ''The Victorian Internet'', Berkley, 1999 {{ISBN|0-425-17169-8}}.</ref>{{rp|190}}

=== Oceanic telegraph cables ===

[[File:Submarine Cornhill 1852.jpg|thumb|The first message is received by the [[Submarine Telegraph Company]] in London from Paris on the [[Foy–Breguet telegraph|Foy–Breguet instrument]] in 1851. The equipment in the background is a Cooke and Wheatstone set for onward transmission.]]
{{Main|Transatlantic telegraph cable||Submarine communications cable}}
[[File:1901 Eastern Telegraph cables.png|thumb|left|upright=1.6|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. 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 (UK)|South Eastern Railway]] company successfully tested a {{convert|2|mi|km|0|spell=on|adj=on|order=flip}} gutta-percha insulated cable with telegraph messages to a ship off the coast of [[Folkestone]].<ref name=Haigh26>{{cite book|last=Haigh|first=K R|title=Cable Ships and Submarine Cables|year=1968|publisher=Adlard Coles Ltd|location=London|pages=26–27}}</ref> The cable to France was laid in 1850 but was almost immediately severed by a French fishing vessel.<ref name=isr>Solymar, Laszlo. ''[http://www.maneyonline.com/doi/abs/10.1179/030801800679233?journalCode=isr The Effect of the Telegraph on Law and Order, War, Diplomacy, and Power Politics] {{Webarchive|url=https://web.archive.org/web/20151016042132/http://www.maneyonline.com/doi/abs/10.1179/030801800679233?journalCode=isr |date=16 October 2015 }}'' in ''Interdisciplinary Science Reviews'', {{nowrap|Vol. 25,}} {{nowrap|No. 3,}} {{nowrap|pp. 204 f.}} 2000. Accessed 1 August 2014.</ref> It was relaid the next year<ref name=isr/> 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, 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 a voltage. Its failure and slow speed of transmission prompted Thomson and [[Oliver Heaviside]] to find better mathematical descriptions of long [[transmission line]]s.<ref name="guarnieri 7-1">{{Cite journal|last=Guarnieri|first=M.|year=2014|title=The Conquest of the Atlantic|journal=IEEE Industrial Electronics Magazine|volume=8|issue=1|pages=53–56/67|doi=10.1109/MIE.2014.2299492|s2cid=41662509}}</ref> The company finally succeeded in 1866 with an improved cable laid by [[SS Great Eastern|SS ''Great Eastern'']], the largest ship of its day, designed by [[Isambard Kingdom Brunel]].<ref>Wilson, Arthur (1994). The Living Rock: The Story of Metals Since Earliest Times and Their Impact on Civilization. p. 203. Woodhead Publishing. {{ISBN|978-1-85573-301-5}}.</ref><ref name="guarnieri 7-1"/>

An overland telegraph from Britain to India was first connected in 1866 but was unreliable so a submarine telegraph cable was connected in 1870.<ref>{{cite book |author=G.C. Mendis |title=Ceylon Under the British |url=https://books.google.com/books?id=ppHNLqowf1cC&pg=PA96 |year=1952 |publisher=Asian Educational Services |isbn=978-81-206-1930-2 |page=96}}</ref> 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, Australia|Darwin]].<ref>Briggs, Asa and Burke, Peter: "A Social History of the Media: From Gutenberg to the Internet", p110. Polity, Cambridge, 2005.</ref>

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]].<ref name="kennedy197110">{{cite journal | jstor=563928 | title=Imperial Cable Communications and Strategy, 1870–1914 | author=Kennedy, P. M. | journal=The English Historical Review |date=October 1971 | volume=86 | issue=341 | pages=728–752 | doi=10.1093/ehr/lxxxvi.cccxli.728}}</ref> 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.<ref>Headrick, D.R., & Griset, P. (2001). Submarine telegraph cables: business and politics, 1838–1939. The Business History Review, 75(3), 543–578.</ref> During [[World War I]], Britain's telegraph communications were almost completely uninterrupted while it was able to quickly cut Germany's cables worldwide.{{r|kennedy197110}}

=== Facsimile ===

[[File:Bain improved facsimile 1850.png|thumb|upright|[[Alexander Bain (inventor)|Alexander Bain]]'s facsimile machine, 1850]]

In 1843, Scottish inventor [[Alexander Bain (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 was successfully tested and approved for a telegraph line between [[Paris]] and [[Lyon]].<ref name="italianunivbio">{{Cite web|url=http://www.itisgalileiroma.it/shed/shed0/shed0/caselli.htm|title=CASELLI|website=www.itisgalileiroma.it|access-date=25 November 2013|archive-date=17 August 2020|archive-url=https://web.archive.org/web/20200817223601/http://www.itisgalileiroma.it/shed/shed0/shed0/caselli.htm|url-status=dead}}</ref><ref name="hebrewuniversity">{{cite web|url=http://chem.ch.huji.ac.il/history/caselli.html |title=The Institute of Chemistry - The Hebrew University of Jerusalem |work=huji.ac.il |url-status=dead |archive-url=https://web.archive.org/web/20080506061432/http://chem.ch.huji.ac.il/history/caselli.html |archive-date=6 May 2008 }}</ref>

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 ''[[:de:Bildtelegrafie|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.
{{clear}}

=== Wireless telegraphy ===

[[File:Marconi at newfoundland.jpg|thumb|Marconi watching associates raising the kite (a "Levitor" by B.F.S. Baden-Powell<ref>[http://aerohistory.org/Wireless/marconi-transatlantique.html "First Atlantic Ocean crossing by a wireless signal"] {{Webarchive|url=https://web.archive.org/web/20220326060429/http://aerohistory.org/Wireless/marconi-transatlantique.html |date=26 March 2022 }}. ''aerohistory.org''. {{Retrieved|access-date=12 July 2012}}</ref>) used to lift the antenna at [[St. John's, Newfoundland and Labrador|St. John's, Newfoundland]], December 1901]]
{{Main|Wireless telegraphy}}
[[File:Post Office Engineers.jpg|thumb|left|Post Office Engineers inspect the [[Marconi Company]]'s equipment at [[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 consensus was that these new waves (similar to light) would be just as short range as light, and, therefore, useless for long range communication.<ref>view was held by [[Nikola Tesla]], [[Oliver Lodge]], [[Alexander Stepanovich Popov]], amongst others (also Brian Regal, ''Radio: The Life Story of a Technology'', page 22)</ref>

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.<ref>{{cite book |author=John W. Klooster |title=Icons of Invention: The Makers of the Modern World from Gutenberg to Gates |url=https://books.google.com/books?id=WKuG-VIwID8C&pg=PA161 |year=2009 |publisher=ABC-CLIO |isbn=978-0-313-34743-6 |page=161}}</ref> 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.<ref>Sungook Hong. ''Wireless: From Marconi's Black-box to the Audion''. MIT Press - 2001, page 21.</ref> 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 {{convert|6|km|mi|frac=2|abbr=on}} 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]].<ref>{{cite web |url=http://www.bbc.co.uk/wales/southeast/sites/flatholm/pages/marconi.shtml |title=Marconi: Radio Pioneer |access-date=12 April 2008 |work=BBC South East Wales}}</ref> His star rising, he was soon sending signals across the [[English Channel]] (1899), from shore to ship (1899) and finally across the Atlantic (1901).<ref>{{cite journal |title=Letters to the Editor: Marconi and the History of Radio |journal=IEEE Antennas and Propagation Magazine |year=2004 |volume=46 |issue=2 |page=130 |doi=10.1109/MAP.2004.1305565}}</ref> 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]].<ref>{{cite book |author=Victor L. Granatstein |title=Physical Principles of Wireless Communications, Second Edition |url=https://books.google.com/books?id=YClQiddGGfkC&pg=PA8 |year=2012 |publisher=CRC Press |isbn=978-1-4398-7897-2 |page=8}}</ref>

Radiotelegraphy proved effective for rescue work in sea [[disaster]]s 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.<ref>{{cite journal|title=The Clifden Station of the Marconi Wireless Telegraph System|journal=Scientific American|date=23 November 1907}}</ref><ref>[http://marconi100.ca/clip/marconi-sydpost19071024.html Second Test of the Marconi Over-Ocean Wireless System Proved Entirely Successful] {{Webarchive|url=https://web.archive.org/web/20131019025942/http://marconi100.ca/clip/marconi-sydpost19071024.html |date=19 October 2013 }}. Sydney Daily Post. 24 October 1907.</ref> 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."

==== Non-radio wireless telegraphy ====
The successful development of radiotelegraphy was preceded by a 50-year history of ingenious but ultimately unsuccessful experiments by inventors to achieve wireless telegraphy by other means.{{Citation needed|date=October 2024}}

=====Ground, water, and air conduction=====
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 the two stations to form a complete [[Electrical network|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 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 {{convert|500|yd|m|0|abbr=off}}.<ref>Fahie, J. J., ''A History of Wireless Telegraphy, 1838–1899'', 1899, p. 29.</ref>

[[File: Wireless Energy Principle.jpg|thumb|Tesla's explanation in the 1919 issue of "Electrical Experimenter" on how he thought his wireless system would work]]

US inventors [[William Henry Ward]] (1871) and [[Mahlon Loomis]] (1872) developed electrical conduction systems based on the erroneous belief that there was an electrified atmospheric stratum accessible at low altitude.<ref>Christopher Cooper, ''The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation'', Race Point Publishing, 2015, pp. 154, 165</ref><ref>Theodore S. Rappaport, Brian D. Woerner, Jeffrey H. Reed, ''Wireless Personal Communications: Trends and Challenges'', Springer Science & Business Media, 2012, pp. 211–215</ref> 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.<ref>Christopher Cooper, ''The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation'', Race Point Publishing, 2015, p. 154</ref><ref>[https://earlyradiohistory.us/sec021.htm Thomas H. White, section  21, MAHLON  LOOMIS]</ref> 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 a distance of a quarter of a mile.<ref name="Christopher Cooper 2015, p. 165">Christopher Cooper, ''The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation'', Race Point Publishing, 2015, p. 165 {{ISBN?}}</ref>

In the 1890s inventor [[Nikola Tesla]] worked on an air and ground conduction [[Wireless power transfer|wireless electric power transmission system]], similar to Loomis',<ref>Proceedings of the United States Naval Institute – Volume 78 – p. 87</ref><ref>W. Bernard Carlson, ''Tesla: Inventor of the Electrical Age'', Princeton University Press – 2013, p. H-45</ref><ref>Marc J. Seifer, ''Wizard: The Life and Times of Nikola Tesla: Biography of a Genius'', Citadel Press – 1996, p. 107</ref> 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<ref>Carlson, W. Bernard (2013). ''Tesla: Inventor of the Electrical Age''. Princeton University Press. p. 301. {{ISBN|1400846552}}</ref><ref name="Christopher Cooper 2015, p. 165"/> and his 1901 large scale application of his ideas, 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.

=====Electrostatic and electromagnetic induction=====
[[File:Pat465971.png|thumb|Thomas Edison's 1891 patent for a ship-to-shore wireless telegraph that used electrostatic induction]]
Both electrostatic and electromagnetic induction were used to develop wireless telegraph systems that saw limited commercial application. In the United States, [[Thomas Edison]], in the mid-1880s, patented an electromagnetic induction system he called "grasshopper telegraphy", which allowed telegraphic signals to jump the short distance between a running train and telegraph wires running parallel to the tracks.<ref>({{US patent|465971}}, ''Means for Transmitting Signals Electrically, US 465971 A'', 1891</ref> This system was successful technically but not economically, as there turned out to be little interest by train travelers in the use of an on-board telegraph service. During the [[Great Blizzard of 1888]], this system was used to send and receive wireless messages from [[railroad|trains]] buried in snowdrifts. The disabled trains were able to maintain communications via their Edison induction wireless telegraph systems,<ref>"Defied the storm's worst-communication always kept up by 'train telegraphy,'" [[New York Times]], March 17, 1888, p. 8. Proquest Historical Newspapers (subscription). Retrieved February 6, 2008.</ref> perhaps the first successful use of wireless telegraphy to send distress calls. Edison would also help to patent a ship-to-shore communication system based on electrostatic induction.<ref>Christopher H. Sterling, ''Encyclopedia of Radio'' 3-Volume Set, Routledge – 2004, p. 833</ref>

The most successful creator of an electromagnetic induction telegraph system was [[William Preece]], chief engineer of Post Office Telegraphs of the [[General Post Office]] (GPO) in the [[United Kingdom]]. Preece first noticed the effect in 1884 when overhead telegraph wires in [[Grays Inn Road]] were accidentally carrying messages sent on buried cables.  Tests in [[Newcastle upon Tyne|Newcastle]] succeeded in sending a quarter of a mile using parallel rectangles of wire.<ref name=Kieve>{{cite book |last=Kieve |first=Jeffrey L. |title=The Electric Telegraph: A Social and Economic History |publisher=David and Charles |year=1973 |oclc=655205099}}</ref>{{rp|243}} In tests across the [[Bristol Channel]] in 1892, Preece was able to telegraph across gaps of about {{convert|5|km|mi|1|abbr=off}}. However, his induction system required extensive lengths of [[Antenna (radio)|antenna wires]], many kilometers long, at both the sending and receiving ends. The length of those sending and receiving wires needed to be about the same length as the width of the water or land to be spanned. For example, for Preece's station to span the [[English Channel]] from [[Dover, England]], to the coast of [[France]] would require sending and receiving wires of about {{convert|30|mi|km|abbr=off}} along the two coasts. These facts made the system impractical on ships, boats, and ordinary islands, which are much smaller than [[Great Britain]] or [[Greenland]]. Also, the relatively short distances that a practical Preece system could span meant that it had few advantages over [[underwater telegraph cable]]s.

=== Telegram services ===
{{redirect|Telegram|the instant messaging service|Telegram (software, linked from hatnote){{!}}Telegram (software)|other uses}}
[[File:1930 Western Union telegram Millsaps College Mississippi State University.jpg|thumb|Western Union telegram (1930)]]
[[File:Western Union Telegram RCC Eisenhower Sept 26 1955.jpg|alt=Western Union telegram sent to President Dwight Eisenhower wishing him a speedy recovery from his heart attack on Sept 26, 1955|thumb|Western Union telegram sent to President Dwight Eisenhower wishing him a speedy recovery from his heart attack on Sept 26, 1955]]

A telegram service is a company or public entity that delivers telegraphed messages directly to the recipient. Telegram services were not inaugurated until [[electric telegraph]]y became available. Earlier optical systems were largely limited to official government and military purposes.

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.<ref name=Phillips/>{{rp|276}} Messages (i.e. telegrams) sent by telegraph could be delivered by [[telegraph messenger]] faster than mail,<ref name=Smith433/> and even in the telephone age, the telegram remained popular for social and business correspondence. At their peak in 1929, an estimated 200 million telegrams were sent.<ref name="Phillips" />{{rp|274}}

In 1919, the Central Bureau for Registered Addresses was established in the [[Financial District, Manhattan |financial district]] of [[New York City]]. The bureau was created to ease the growing problem of messages being delivered to the wrong recipients. To combat this issue, the bureau offered telegraph customers the option to register unique code names for their telegraph addresses. Customers were charged $2.50 per year per code. By 1934, 28,000 codes had been registered.<ref>{{Citation |last=James |first=Gleick |title=The information : a history, a theory, a flood |date= 2011 |url= http://worldcat.org/oclc/689998325 |publisher=Books on Tape |isbn= 978-0-307-91498-9 |oclc=689998325 |access-date= 2021-04-12}}</ref>

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.<ref>Tom Standage, ''The Victorian Internet'', Afterword, Walker & Co, 2007 {{ISBN|978-0-802-71879-2}}.</ref> Where telegram services still exist, the transmission method between offices is no longer by telegraph, but by [[telex]] or [[Internet Protocol|IP]] link.<ref>{{cite web |url= https://arstechnica.com/information-technology/2013/06/telegram-not-dead-stop/ |title=TELEGRAM NOT DEAD. STOP. |access-date=14 May 2019 |work=Ars Technica |date=19 June 2013 }}</ref>

==== 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.<ref>{{cite book |last1= Hochfelder |first1=David|title= The Telegraph in America, 1832–1920 |date=2012 |publisher=The Johns Hopkins University Press |page=79 |url= https://books.google.com/books?id=fUDxx_bMVQUC&pg=PA79 |isbn= 978-1-42140747-0}}</ref> According to another study, the mean length of the telegrams sent in the UK before 1950 was 14.6 words or 78.8 characters.<ref name="Frehner">{{cite book |last1= Frehner |first1=Carmen|title=Email, SMS, MMS: The Linguistic Creativity of Asynchronous Discourse in the New Media Age |date=2008 |publisher=Peter Lang AG |location=Bern |pages=187, 191 |url= https://books.google.com/books?id=wiVz8dDW8-cC&pg=PA191 |isbn= 978-303911451-1}}</ref> For German telegrams, the mean length is 11.5 words or 72.4 characters.<ref name= "Frehner"/> At the end of the 19th century, the average length of a German telegram was calculated as 14.2 words.<ref name="Frehner"/>

=== Telex ===
{{Main article|Telex}}
[[File:ITT Creed Model 23B teleprinter (46479610772).jpg|thumb|ITT Creed Model 23B teleprinter 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 {{lang|de|[[Reichspost]]}} (the German imperial 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]] [[frequency-division multiplexing|multiplexing]], making telex the least expensive method of reliable long-distance communication.<ref>{{Cite web |title=Telegraphy and Telex |url=https://new.siemens.com/global/en/company/about/history/technology/information-and-communications-technology/telegraphy-and-telex.html |access-date=2022-10-14 |website=siemens.com Global Website |language=en}}</ref> Telex was introduced into Canada in July 1957, and the United States in 1958.<ref>Phillip R. Easterlin, "Telex in New York", Western Union Technical Review, April 1959: 45</ref> A new code, [[ASCII]], was introduced in 1963 by the [[American Standards Association]]. ASCII was a seven-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.<ref name="Kieve"/>{{rp|248}} The decline began with the growth of the use of the [[telephone]].<ref name="Kieve"/>{{rp|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 its patent battle with [[Alexander Graham Bell]] because it believed the telephone was not a threat to its 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,<ref name=Phillips/>{{rp|276–277}} and nearly 2 million by 1900.<ref name="Standage"/>{{rp|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,<ref name=Phillips/>{{rp|274}} but by 1900 the telegraph was definitely in decline.<ref name=Phillips/>{{rp|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.<ref name=Phillips/>{{rp|277}} After the [[Second World War]] new technology improved communication in the telegraph industry.<ref name= "EB">{{cite encyclopedia |title = The End of The Telegraph Era |encyclopedia = Britannica |date = 22 July 2024 |url = https://www.britannica.com/technology/telegraph/The-end-of-the-telegraph-era}}</ref> Telegraph lines continued to be an important means of distributing news feeds from [[news agency|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.<ref name=Phillips/>{{rp|277}} In the modern era, the telegraph that began in 1837 has been gradually replaced by [[digital data]] transmission based on [[computer]] [[information system]]s.<ref name="EB" />