Editing Electrical telegraph (section)

== Commercial telegraphy ==
===Cooke and Wheatstone system===
{{see also|Electrical telegraphy in the United Kingdom}}
[[File:GWR Cooke and Wheatstone double needle telegraph instrument.jpg|thumb|GWR Cooke and Wheatstone double needle telegraph instrument]]
The first commercial electrical telegraph was the [[Cooke and Wheatstone telegraph|Cooke and Wheatstone system]]. A demonstration four-needle system was installed on the [[Euston railway station|Euston]] to [[Camden Town]] section of [[Robert Stephenson]]'s [[London and Birmingham Railway]] in 1837 for signalling rope-hauling of locomotives.<ref>{{cite web |url=http://www.connected-earth.com/journeys/Firstgenerationtechnologies/Thetelegraph/Thetelegraphicagedawns/index.htm |title=The telegraphic age dawns |website=BT Group Connected Earth Online Museum |access-date=1 December 2010 |archive-url=https://web.archive.org/web/20130219081333/http://www.connected-earth.com/journeys/Firstgenerationtechnologies/Thetelegraph/Thetelegraphicagedawns/index.htm |archive-date=19 February 2013}}</ref> It was rejected in favour of pneumatic whistles.<ref name="Bowers 129">Bowers, p. 129</ref> Cooke and Wheatstone had their first commercial success with a system installed on the [[Great Western Railway]] over the {{convert|13|mi|km}} from [[Paddington station]] to [[West Drayton]] in 1838.{{sfn|Huurdeman|2003|p=67}} This was a five-needle, six-wire<ref name="Bowers 129"/> system, and had the major advantage of displaying the letter being sent so operators did not need to learn a code. The insulation failed on the underground cables between Paddington and West Drayton,{{sfn|Huurdeman|2003|pp=67–68}}{{sfn|Beauchamp|2001|p= 35}} and when the line was extended to [[Slough]] in 1843, the system was converted to a one-needle, two-wire configuration with uninsulated wires on poles.{{sfn|Huurdeman|2003|p=69}} The cost of installing wires was ultimately more economically significant than the cost of training operators. The one-needle telegraph proved highly successful on British railways, and 15,000 sets were in use at the end of the nineteenth century; some remained in service in the 1930s.{{sfn|Huurdeman|2003|pp=67–69}} The [[Electric Telegraph Company]], the world's first public telegraphy company, was formed in 1845 by financier [[John Lewis Ricardo]] and Cooke.<ref>Nichols, John (1967). ''The Gentleman's magazine, Volumes 282–283.'' p. 545. University of California</ref><ref>{{cite web |url=https://www.bbc.co.uk/history/british/victorians/victorian_technology_01.shtml |title=Victorian Technology |author=Paul Atterbury |publisher=BBC}}</ref>

===Wheatstone ABC telegraph===
[[File:ABC machine.jpg|thumb|left|upright|A [[magneto]]-powered Wheatstone A. B. C. telegraph with the horizontal "communicator" dial, the inclined "indicator" dial and crank handle for the magneto that generated the electrical signal.]]
Wheatstone developed a practical alphabetical system in 1840 called the A.B.C. System, used mostly on private wires. This consisted of a "communicator" at the sending end and an "indicator" at the receiving end. The communicator consisted of a circular dial with a pointer and the 26 letters of the alphabet (and four punctuation marks) around its circumference. Against each letter was a key that could be pressed. A transmission would begin with the pointers on the dials at both ends set to the start position. The transmitting operator would then press down the key corresponding to the letter to be transmitted. In the base of the communicator was a [[magneto]] actuated by a handle on the front. This would be turned to apply an alternating voltage to the line. Each half cycle of the current would advance the pointers at both ends by one position. When the pointer reached the position of the depressed key, it would stop and the magneto would be disconnected from the line. The communicator's pointer was geared to the magneto mechanism. The indicator's pointer was moved by a polarised electromagnet whose [[Armature (electrical)|armature]] was coupled to it through an [[escapement]]. Thus the alternating line voltage moved the indicator's pointer on to the position of the depressed key on the communicator. Pressing another key would then release the pointer and the previous key, and re-connect the magneto to the line.<ref>{{cite web |url=https://www.youtube.com/watch?v=o5RW31DLaVs |title=Telegraph – A working ABC telegraph from prof. Ch. Wheatstone |website=[[YouTube]] |date=5 June 2018}}</ref> These machines were very robust and simple to operate, and they stayed in use in Britain until well into the 20th century.<ref>{{Citation |last=Freebody |first=J. W. |title=Telegraphy |place=London |publisher=Sir Isaac Pitman & Sons, Ltd. |year=1958 |chapter=Historical Survey of Telegraphy |pages=30, 31}}</ref><ref>{{cite web |url=http://www.samhallas.co.uk/telhist1/telehist.htm |title=A Short History of Telegraphy |last1=Hobbs |first1=Alan G. |last2=Hallas |first2=Sam}}</ref>

===Morse system===
{{main|Morse code}}
[[File:The first telegram. Professor Samuel Morse sending the despatch as dictated by Miss Annie Ellsworth.jpg|thumb|1900 illustration of Professor Morse sending [[Baltimore–Washington telegraph line|the first long-distance message]]{{snd}}"WHAT HATH GOD WROUGHT"{{snd}}on 24 May 1844]]

The Morse system uses a single wire between offices. At the sending station, an operator taps on a switch called a [[telegraph key]], spelling out text messages in [[Morse code]]. Originally, the armature was intended to make marks on paper tape, but operators learned to interpret the clicks and it was more efficient to write down the message directly.

In 1851, a conference in Vienna of countries in the German-Austrian Telegraph Union (which included many central European countries) adopted the Morse telegraph as the system for international communications.<ref>{{cite book |first=Laurence |last=Turnbull |title=Electro-magnetic telegraph |page=77 |location=Philadelphia |publisher=A. Hart |year=1853 |oclc=60717772}}</ref> The [[international Morse code]] adopted was considerably modified from the original [[American Morse code]], and was based on a code used on Hamburg railways ([[Friedrich Clemens Gerke|Gerke]], 1848).<ref>{{cite book |first=Lewis |last=Coe |title=The Telegraph: A History of Morse's Invention and Its Predecessors in the United States |page=69 |publisher=McFarland |year=2003 |isbn=0786418087}}</ref> A common code was a necessary step to allow direct telegraph connection between countries. With different codes, additional operators were required to translate and retransmit the message. In 1865, a conference in Paris adopted Gerke's code as the International Morse code and was henceforth the international standard. The US, however, continued to use American Morse code internally for some time, hence international messages required retransmission in both directions.<ref>{{cite book |first=Andrew L. |last=Russell |title=Open Standards and the Digital Age |page=36 |publisher=Cambridge University Press |year=2014 |isbn=978-1107039193}}</ref>

In the United States, the Morse/Vail telegraph was [[timeline of North American telegraphy|quickly deployed in the two decades following the first demonstration]] in 1844. The [[First transcontinental telegraph|overland telegraph]] connected the west coast of the continent to the east coast by 24 October 1861, bringing an end to the [[Pony Express]].<ref>Today in History – 24 October, [https://www.loc.gov/item/today-in-history/october-24 The Transcontinental Telegraph and the End of the Pony Express], Library of Congress, retrieved 3 February 2017.</ref>

===Foy–Breguet system===
{{Main|Foy–Breguet telegraph}}
[[File:Foy-Breguet telegraph display.jpg|left|thumb|[[Foy–Breguet telegraph]] displaying the letter "Q"]]
France was slow to adopt the electrical telegraph, because of the extensive [[optical telegraph]] system built during the [[Napoleonic era]]. There was also serious concern that an electrical telegraph could be quickly put out of action by enemy saboteurs, something that was much more difficult to do with optical telegraphs which had no exposed hardware between stations. The [[Foy-Breguet telegraph]] was eventually adopted. This was a two-needle system using two signal wires but displayed in a uniquely different way to other needle telegraphs. The needles made symbols similar to the [[Claude Chappe|Chappe]] optical system symbols, making it more familiar to the telegraph operators. The optical system was decommissioned starting in 1846, but not completely until 1855. In that year the Foy-Breguet system was replaced with the Morse system.<ref>Holzmann & Pehrson, pp. 93–94</ref>

===Expansion===
As well as the rapid expansion of the use of the telegraphs along the railways, they soon spread into the field of mass communication with the instruments being installed in [[post office]]s. The era of mass personal communication had begun. Telegraph networks were expensive to build, but financing was readily available, especially from London bankers. By 1852, National systems were in operation in major countries:<ref>Christine Rider, ed., ''Encyclopedia of the Age of the Industrial Revolution, 1700–1920'' (2007) 2:440.</ref><ref>{{cite web |first=Taliaferro Preston |last=Shaffner |url=https://archive.org/details/telegraphmanualc00shafrich |title=The Telegraph Manual: A Complete History and Description of the Semaphoric, Electric and Magnetic Telegraphs of Europe, Asia, Africa, and America, Ancient and Modern: with Six Hundred and Twenty-five Illustrations |year=1867}}</ref> 
{| class="wikitable"
|+ Extent of the telegraph in 1852
|-
!Country||style="width: 14em;"|Company or system||Miles or kilometers<br>of wire||ref
|-
|United States||20 companies||{{convert|23000|mi|km|disp=or|abbr=on}}||<ref>Richard B. Du Boff, "Business Demand and the Development of the Telegraph in the United States, 1844–1860." ''Business History Review'' 54#4 (1980): 459–479.</ref>
|-
|[[Electrical telegraphy in the United Kingdom|United Kingdom]]||[[Electric Telegraph Company]], [[Magnetic Telegraph Company]], and others||{{convert|2200|mi|km|disp=or|abbr=on}}||<ref>John Liffen, "The Introduction of the Electric Telegraph in Britain, a Reappraisal of the Work of Cooke and Wheatstone." ''International Journal for the History of Engineering & Technology'' (2013).</ref>
|-
|Prussia||Siemens system||{{convert|1400|mi|km|disp=or|abbr=on}}|| 
|-
|Austria|| Siemens system||{{convert|1000|mi|km|disp=or|abbr=on}}||
|-
|Canada|| || {{convert|900|mi|km|disp=or|abbr=on}}||
|-
|France||optical systems dominant||{{convert|700|mi|km|disp=or|abbr=on}}|| 
|}

The New York and Mississippi Valley Printing Telegraph Company, for example, was created in 1852 in Rochester, New York and eventually became the [[Western Union|Western Union Telegraph Company]].<ref>{{cite journal |last1=Enns |first1=Anthony |title=Spiritualist Writing Machines: Telegraphy,Typtology, Typewriting |url=https://scholarworks.umass.edu/cpo/vol4/iss1/11/ |journal=Communication +1 |date=September 2015 |volume=4 |issue=1 |doi=10.7275/R5M61H51 |s2cid=14674389 |quote=Article 11}}</ref> Although many countries had telegraph networks, there was no ''worldwide'' interconnection. Message by post was still the primary means of communication to countries outside Europe.

{| class="wikitable"
|+ Worldwide postal speeds in 1852
|-
! colspan="2"|A letter by post from London took
|-
! days !! to reach<ref>{{Citation |last=Roberts |first=Steven |title=A History of the Telegraph Companies in Britain between 1838–1868 |year=2012 |url=http://distantwriting.co.uk/companiesandforeigntraffic.html |access-date=8 May 2017}}</ref>
|-
| 12 || New York in the United States
|-
| 13 || Alexandria in Egypt
|-
| 19 || Constantinople in Ottoman Turkey
|-
| 33 || Bombay in India (west coast of India)
|-
| 44 || Calcutta in Bengal (east coast of India)
|-
| 45 || Singapore
|-
| 57 || Shanghai in China
|-
| 73 || Sydney in Australia
|}

Telegraphy was introduced in [[Central Asia]] during the 1870s.<ref>{{Cite book |last=Khalid |first=Adeeb |title=The Politics of Muslim Cultural Reform: Jadidism in Central Asia |publisher=University of California Press |year=1998 |isbn=0-520-21356-4 |location=Berkeley and Los Angeles |pages=60–61 |chapter=2: The Making of a Colonial Society}}</ref>

===Telegraphic improvements===
[[File: Components of the electromechanical telegraph network. Proce Wellcome V0025510.jpg|thumb|left|Wheatstone automated telegraph network equipment]]
A continuing goal in telegraphy was to reduce the cost per message by reducing hand-work, or increasing the sending rate. There were many experiments with moving pointers, and various electrical encodings. However, most systems were too complicated and unreliable. A successful expedient to reduce the cost per message was the development of [[telegraphese]].

The first system that did not require skilled technicians to operate was Charles Wheatstone's ABC system in 1840 in which the letters of the alphabet were arranged around a clock-face, and the signal caused a needle to indicate the letter. This early system required the receiver to be present in real time to record the message and it reached speeds of up to 15 words a minute.

In 1846, [[Alexander Bain (inventor)|Alexander Bain]] patented a chemical telegraph in Edinburgh. The signal current moved an iron pen across a moving paper tape soaked in a mixture of ammonium nitrate and potassium ferrocyanide, decomposing the chemical and producing readable blue marks in Morse code. The speed of the printing telegraph was 16 and a half words per minute, but messages still required translation into English by live copyists. Chemical telegraphy came to an end in the US in 1851, when the Morse group defeated the Bain patent in the US District Court.<ref>{{cite book |last=Oslin |first=George P |title=The Story of Telecommunications |publisher=Mercer University Press |year=1992 |page=69 |isbn=9780865544185}}</ref>

For a brief period, starting with the New York–Boston line in 1848, some telegraph networks began to employ sound operators, who were trained to understand Morse code aurally. Gradually, the use of sound operators eliminated the need for telegraph receivers to include register and tape. Instead, the receiving instrument was developed into a "sounder", an electromagnet that was energized by a current and attracted a small iron lever. When the sounding key was opened or closed, the sounder lever struck an anvil. The Morse operator distinguished a dot and a dash by the short or long interval between the two clicks. The message was then written out in long-hand.<ref>{{cite book |last=Oslin |first=George P |title=The Story of Telecommunications |publisher=Mercer University Press |year=1992 |page=67 |isbn=9780865544185}}</ref>

[[Royal Earl House]] developed and patented a letter-printing telegraph system in 1846 which employed an alphabetic keyboard for the transmitter and automatically printed the letters on paper at the receiver,<ref>{{cite web |url=http://blog.gatunka.com/2014/04/14/letter-printing-telegraph-us-patent-4464/ |title=Royal Earl House Printing-Telegraph Patent #4464, 1846 |access-date=25 April 2014}}</ref> and followed this up with a steam-powered version in 1852.<ref>{{cite web |url=http://blog.gatunka.com/2014/04/15/steam-powered-letter-printing-telegraph-us-patent-9505/ |title=Royal Earl House Steam-Powered Printing-Telegraph Patent #9505, 1852 |access-date=25 April 2014}}</ref> Advocates of printing telegraphy said it would eliminate Morse operators' errors. The House machine was used on four main American telegraph lines by 1852. The speed of the House machine was announced as 2600 words an hour.<ref>{{cite book |last=Oslin |first=George P |title=The Story of Telecommunications |publisher=Mercer University Press |year=1992 |page=71 |isbn=9780865544185}}</ref>

[[File:Clavier Baudot.jpg|thumb|upright=1.5|A Baudot keyboard, 1884]]
[[David Edward Hughes]] invented the printing telegraph in 1855; it used a keyboard of 26 keys for the alphabet and a spinning type wheel that determined the letter being transmitted by the length of time that had elapsed since the previous transmission. The system allowed for automatic recording on the receiving end. The system was very stable and accurate and became accepted around the world.<ref>{{cite web |url=http://people.clarkson.edu/~ekatz/scientists/hughes.html |title=David Edward Hughes |access-date=29 September 2010 |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>

The next improvement was the [[Baudot code]] of 1874. French engineer [[Émile Baudot]] patented a printing telegraph in which the signals were translated automatically into typographic characters. Each character was assigned a five-bit code, mechanically interpreted from the state of five on/off switches. Operators had to maintain a steady rhythm, and the usual speed of operation was 30 words per minute.{{sfn|Beauchamp|2001|pp=394–395}}

By this point, reception had been automated, but the speed and accuracy of the transmission were still limited to the skill of the human operator. The first practical automated system was patented by Charles Wheatstone. The message (in [[Morse code]]) was typed onto a piece of perforated tape using a keyboard-like device called the 'Stick Punch'. The transmitter automatically ran the tape through and transmitted the message at the then exceptionally high speed of 70 words per minute.

====Teleprinters====
{{main|Teleprinter|Telex}}
{{more citations needed section|date=January 2020}}
[[File:Phelps' Electro-motor Printing Telegraph.jpg|thumb|Phelps' Electro-motor Printing Telegraph from {{circa|1880}}, the last and most advanced telegraphy mechanism designed by [[George May Phelps]]]]
[[File:Bundesarchiv Bild 183-2008-0516-500, Fernschreibmaschine mit Telefonanschluss.jpg|thumb|right|A Creed Model 7 teleprinter in 1930]]
[[File:Teletype-IMG 7289.jpg|right|thumb|upright=1|[[Teletype Model 33]] ASR (Automatic Send and Receive)]]
An early successful [[teleprinter]] was invented by [[Frederick G. Creed]]. In [[Glasgow]] he created his first keyboard perforator, which used compressed air to punch the holes. He also created a reperforator (receiving perforator) and a printer. The reperforator punched incoming Morse signals onto paper tape and the printer decoded this tape to produce alphanumeric characters on plain paper. This was the origin of the Creed High Speed Automatic Printing System, which could run at an unprecedented 200 words per minute. His system was adopted by the ''[[Daily Mail]]'' for daily transmission of the newspaper contents.

With the invention of the [[teletypewriter]], telegraphic encoding became fully automated. Early teletypewriters used the ITA-1 [[Baudot code]], a five-bit code. This yielded only thirty-two codes, so it was over-defined into two "shifts", "letters" and "figures". An explicit, unshared shift code prefaced each set of letters and figures. In 1901, Baudot's code was modified by [[Donald Murray (inventor)|Donald Murray]].

In the 1930s, teleprinters were produced by [[Teletype Corporation|Teletype]] in the US, [[Creed & Company|Creed]] in Britain and [[Siemens]] in Germany.

By 1935, message routing was the last great barrier to full automation. Large telegraphy providers began to develop systems that used [[telephone exchange|telephone-like rotary dialling]] to connect teletypewriters. These resulting systems were called "Telex" (TELegraph EXchange). Telex machines first performed rotary-telephone-style [[pulse dialling]] for [[circuit switching]], and then sent data by [[ITA2]]. This "type A" Telex routing functionally automated message routing.

The first wide-coverage Telex network was implemented in Germany during the 1930s<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 |url-status=live |access-date=25 March 2021 |archive-url=https://web.archive.org/web/20190726052037/https://new.siemens.com/global/en/company/about/history/technology/information-and-communications-technology/telegraphy-and-telex.html |archive-date=26 July 2019}}</ref> as a network used to communicate within the government.

At the rate of 45.45 (±0.5%) [[baud]] – considered speedy at the time – 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.

Automatic teleprinter exchange service was introduced into Canada by [[CPR Telegraphs]] and [[CN Telegraph]] in July 1957 and in 1958, [[Western Union]] started to build a Telex network in the United States.<ref>Phillip R. Easterlin, "Telex in New York", Western Union Technical Review, April 1959: 45</ref>

====The harmonic telegraph====
{{main|Invention of the telephone}}
{{see also|Acoustic telegraphy}}
The most expensive aspect of a telegraph system was the installation – the laying of the wire, which was often very long. The costs would be better covered by finding a way to send more than one message at a time through the single wire, thus increasing revenue per wire. Early devices included the [[duplex (telegraph)|duplex]] and the [[Quadruplex telegraph|quadruplex]] which allowed, respectively, one or two telegraph transmissions in each direction. However, an even greater number of channels was desired on the busiest lines. In the latter half of the 1800s, several inventors worked towards creating a method for doing just that, including [[Charles Bourseul]], [[Thomas Edison]], [[Elisha Gray]], and [[Alexander Graham Bell]].

One approach was to have resonators of several different frequencies act as carriers of a modulated on-off signal. This was the harmonic telegraph, a form of [[Multiplexing#Frequency-division multiplexing|frequency-division multiplexing]]. These various frequencies, referred to as harmonics, could then be combined into one complex signal and sent down the single wire. On the receiving end, the frequencies would be separated with a matching set of resonators.

With a set of frequencies being carried down a single wire, it was realized that the human voice itself could be transmitted electrically through the wire. This effort led to the [[invention of the telephone]]. (While the work toward packing multiple telegraph signals onto one wire led to telephony, later advances would pack multiple voice signals onto one wire by increasing the bandwidth by modulating frequencies much higher than human hearing. Eventually, the bandwidth was widened much further by using laser light signals sent through fiber optic cables. Fiber optic transmission can carry 25,000 telephone signals simultaneously down a single fiber.<ref>{{Cite web |url=https://www.explainthatstuff.com/fiberoptics.html |title=How does fiber optics work? |date=11 June 2006}}</ref>)

===Oceanic telegraph cables===
[[File:1891 Telegraph Lines.jpg|right|thumb|upright=1.51|Major telegraph lines in 1891]]
{{Main|Transatlantic telegraph cable||Submarine communications cable}}
Soon after the first successful telegraph systems were operational, the possibility of transmitting messages across the sea by way of [[submarine communications cable]]s was first proposed. One of the primary technical challenges was to sufficiently insulate the submarine cable to prevent the electric current from leaking out into the water. In 1842, a Scottish surgeon [[William Montgomerie]]<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> introduced [[gutta-percha]], the adhesive juice of the ''[[Palaquium gutta]]'' tree, to Europe. [[Michael Faraday]] and Wheatstone soon discovered the merits of gutta-percha as an insulator, and in 1845, the latter suggested that it should be employed to cover the wire which was proposed to be laid from [[Dover]] to [[Calais]]. Gutta-percha was used as insulation on a wire laid across the [[Rhine]] between [[Cologne-Deutz|Deutz]] and [[Cologne]].<ref>Bright, Charles (1898). ''[[iarchive:cihm_00867|Submarine telegraphs [microform] : their history, construction, and working]] : founded in part on Wünschendorff's 'Traité de télé graphie sous-marine''. Canadiana.org. London: C. Lockwood. p. 251.</ref> In 1849, [[C. V. Walker]], electrician to the [[South Eastern Railway (UK)|South Eastern Railway]], submerged a {{convert|2|mi|km}} wire coated with gutta-percha off the coast from Folkestone, which was tested successfully.<ref name=Haigh26/>

[[John Watkins Brett]], an engineer from [[Bristol]], sought and obtained permission from [[Louis-Philippe]] in 1847 to establish [[telegraph|telegraphic communication]] between France and England. The first undersea cable was laid in 1850, connecting the two countries and was followed by connections to Ireland and the Low Countries.

The [[Atlantic Telegraph Company]] was formed in [[London]] in 1856 to undertake to construct a commercial telegraph cable across the Atlantic Ocean. It was successfully completed on 18 July 1866 by the ship [[SS Great Eastern|SS ''Great Eastern'']], captained by [[James Anderson (sea captain)|Sir James Anderson]], after many mishaps along the way.<ref>{{cite book |last=Wilson |first=Arthur |year=1994 |title=The Living Rock: The Story of Metals Since Earliest Times and Their Impact on Civilization |page=203 |publisher=Woodhead Publishing |isbn=9781855733015}}</ref> John Pender, one of the men on the Great Eastern, later founded several telecommunications companies primarily laying cables between Britain and Southeast Asia.<ref>{{Cite journal |last=Müller |first=Simone |date=2010 |title=The Transatlantic Telegraphs and the 'Class of 1866' – the Formative Years of Transnational Networks in Telegraphic Space, 1858–1884/89 |journal=Historical Social Research / Historische Sozialforschung |volume=35 |issue=1 (131) |pages=237–259 |jstor=20762437 |issn=0172-6404}}</ref> Earlier transatlantic [[submarine communications cable|submarine cables]] installations were attempted in 1857, 1858 and 1865. The 1857 cable only operated intermittently for a few days or weeks before it failed. The study of underwater telegraph cables accelerated interest in mathematical analysis of very long [[transmission line]]s. The telegraph lines from Britain to India were connected in 1870. (Those several companies combined to form the ''Eastern Telegraph Company'' in 1872.) The HMS ''Challenger'' expedition in 1873–1876 mapped the ocean floor for future underwater telegraph cables.<ref>{{Cite book |last=Starosielski |first=Nicole |title=The Undersea Network |date=2015 |publisher=Duke University Press |isbn=978-0-8223-7622-4 |page=203 |chapter=Cabled Depths: The Aquatic Afterlives of Signal Traffic |doi=10.1215/9780822376224 |s2cid=114607440}}</ref>

Australia was first linked to the rest of the world in October 1872 by a submarine telegraph cable at Darwin.<ref>{{cite book |last1=Briggs |first1=Asa |last2=Burke |first2=Peter |title=A Social History of the Media: From Gutenberg to the Internet |page=110 |publisher=Polity |location=Cambridge |year=2005 |isbn=9780745635118}}</ref> This brought news reports from the rest of the world.<ref>{{cite book |last1=Conley |first1=David |last2=Lamble |first2=Stephen |year=2006 |title=The Daily Miracle: An introduction to Journalism |edition=3 |publisher=Oxford University Press |location=Australia |pages=305–307}}</ref> The telegraph across the Pacific was completed in 1902, finally encircling the world.

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>{{cite journal |last1=Headrick |first1=D.R. |last2=Griset |first2=P. |year=2001 |title=Submarine telegraph cables: business and politics, 1838–1939 |journal=The Business History Review |volume=75 |issue=3 |pages=543–578 |doi=10.2307/3116386 |jstor=3116386 |s2cid=153560358}}</ref>

===Cable and Wireless Company===
[[File:1901 Eastern Telegraph cables.png|thumb|upright=1.51|The Eastern Telegraph Company network in 1901]]
{{main|Cable & Wireless plc}}
[[Cable & Wireless plc|Cable & Wireless]] was a British telecommunications company that traced its origins back to the 1860s, with Sir [[John Pender]] as the founder,<ref>{{cite web |url=http://www.atlantic-cable.com/CableCos/CandW/Pender/ |title=Sir John Pender}}</ref> although the name was only adopted in 1934. It was formed from successive mergers including: 
*The Falmouth, Malta, Gibraltar Telegraph Company
*The British Indian Submarine Telegraph Company
*The Marseilles, Algiers and Malta Telegraph Company
*The Eastern Telegraph Company<ref>{{cite web |url=http://www.atlantic-cable.com/CableCos/CandW/Eastern/ |title=Evolution of Eastern Telegraph Company}}</ref>
*The Eastern Extension Australasia and China Telegraph Company
*The Eastern and Associated Telegraph Companies<ref>{{cite web |url=http://www.atlantic-cable.com/CableCos/CandW/EATC/ |title=Origins of the Eastern & Associated Telegraph Companies}}</ref>