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A SEMAPHORE TELEGRAPH is a 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 century. They were much faster than post riders for conveying a message over long distances, and also had cheaper long-term operating costs, once constructed. Semaphore
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 distance that an optical telegraph can bridge is limited by geography and weather; thus, in practical use, most optical telegraphs used lines of relay stations to bridge longer distances. This also 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 (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).

CONTENTS

* 1 Etymology and terminology

* 2 History

* 2.1 Early designs

* 2.2 Chappe system

* 2.2.1 Development * 2.2.2 Technical operation

* 2.3 Other systems

* 3 Use in various countries

* 3.1 France
France
* 3.2 Sweden
Sweden
* 3.3 United Kingdom * 3.4 Other countries

* 4 In popular culture * 5 See also * 6 References * 7 Further reading * 8 External links

ETYMOLOGY AND TERMINOLOGY

The word semaphore was coined in 1801 by the French inventor of the semaphore line itself, Claude Chappe . He composed it from the Greek elements σῆμα (sêma, "sign"); and from φορός (phorós, "carrying"), or φορά (phorá, "a carrying") from φέρειν (phérein, "to bear"). Chappe also coined the word telegraph . The word semaphoric was first printed in English in 1808: "The newly constructed Semaphoric telegraphs", referring to the destruction of telegraphs in France. The word semaphore was first printed in English in 1816: "The improved Semaphore
Semaphore
has been erected on the top of the Admiralty ", referring to the installation of a simpler telegraph invented by Sir Home Popham
Sir Home Popham
. Semaphore
Semaphore
telegraphs are also called "optical telegraphs", "shutter telegraph chains", "Chappe telegraphs" or "Napoleonic semaphore".

HISTORY

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EARLY DESIGNS

Illustration showing Robert Hooke's proposed system. At top are various symbols that might be used; ABCE indicates the frame, and D the screen behind which each of the symbols are hidden when not in use.

Optical telegraphy dates from ancient times, in the form of hydraulic telegraphs , torches (as used by ancient cultures since the discovery of fire) and smoke signals . Modern design of semaphores was first foreseen by the British polymath Robert Hooke , who gave a vivid and comprehensive outline of visual telegraphy to the Royal Society in an 1684 submission in which he outlined many practical details. The system (which was motivated by military concerns, following the recent Battle of Vienna
Battle of Vienna
in 1683) was never put into practice. Sir Richard Lovell Edgeworth 's proposed optical telegraph for use in Ireland. The rotational position of each one of the four indicaters represented a number 1-7 (0 being "rest"), forming a four-digit number. The number stood for a particular word in a codebook.

One of the first experiments of optical signalling was carried out by the Anglo-Irish landowner and inventor, Sir Richard Lovell Edgeworth in 1767. He placed a bet with his friend, the horse racing gambler Lord Marsh, that he could transmit knowledge of the outcome of the race in just one hour. Using a network of signalling sections erected on high ground, the signal would be observed from one station to the next by means of a telescope . The signal itself consisted of a large pointer that could be placed into eight possible positions in 45 degree increments. A series of two such signals gave a total 64 code elements and a third signal took it up to 512. He returned to his idea in 1795, after hearing of Chappe's system.

CHAPPE SYSTEM

Demonstration of the semaphore

Credit for the first successful optical telegraph goes to the French engineer Claude Chappe and his brothers in 1792, who succeeded in covering France
France
with a network of 556 stations stretching a total distance of 4,800 kilometres (3,000 mi). Le système Chappe was used for military and national communications until the 1850s.

Development

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. France
France
was surrounded by the forces of Britain , the Netherlands
Netherlands
, Prussia , Austria
Austria
, and Spain
Spain
, the cities of Marseille
Marseille
and Lyon
Lyon
were in revolt, and the British Fleet held Toulon . The only advantage France
France
held was the lack of cooperation between the allied forces due to their inadequate lines of communication. In the summer of 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 11am, 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 (9.9 mi). The first means used a combination of black and white panels, clocks, telescopes, and codebooks to send their message.

The Chappes carried out experiments during the next two years, and on two occasions their apparatus at Place de l\'Étoile , Paris
Paris
was destroyed by mobs who thought they were communicating with royalist forces. However, in the summer of 1792 Claude was appointed Ingénieur-Télégraphiste and charged with establishing a line of stations between Paris
Paris
and Lille
Lille
, a distance of 230 kilometres (about 143 miles). 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. The first symbol of a message to Lille
Lille
would pass through 15 stations in only nine minutes. The speed of the line varied with the weather, but the line to Lille
Lille
typically transferred 36 symbols, a complete message, in about 32 minutes. Another line of 50 stations was completed in 1798, covering 488 km between Paris
Paris
and Strasbourg
Strasbourg
.

Technical Operation

Diagram showing the Chappe system, as used simply for signalling letters and numbers (though it could also be used in an encoded form)

The Chappe brothers determined by experiment that it was easier to see the angle of a rod than to see the presence or absence of a panel. Their semaphore was composed of two black movable wooden arms, connected by a cross bar; the positions of all three of these components together indicated an alphabetic letter. With counterweights (named forks) on the arms, the Chappe system was controlled by only two handles and was mechanically simple and reasonably robust. Each of the two 2-metre-long arms could display seven positions, and the 4.6-metre-long cross bar connecting the two arms could display four different angles, for a total of 196 symbols (7×7×4). Night operation with lamps on the arms was unsuccessful. To speed up transmission and to provide some semblance of security, a code book was developed for use with semaphore lines. The Chappes' corporation used a code that took 92 of the basic symbols two at a time to yield 8,464 coded words and phrases.

The revised Chappe system of 1795 provided not only a set of codes but also an operational protocol intended to maximize line throughput . Symbols were transmitted in cycles of "2 steps and 3 movements."

* STEP 1, MOVEMENT 1 (SETUP): The indicator arms were turned to align with the cross bar, forming a non-symbol. The crossbar was then moved into position for the current symbol. * STEP 1, MOVEMENT 2 (TRANSMISSION): The indicator arms were positioned for the current symbol. The operator then waited for the downline station to copy it. * STEP 2, MOVEMENT 3 (COMPLETION): The cross bar was turned to a vertical or horizontal position, indicating the end of a cycle.

In this manner, each symbol could propagate down the line as quickly as operators could successfully copy it, with acknowledgement and flow control built into the protocol. A rate of 2-3 symbols per minute was typical.

OTHER SYSTEMS

From 1803 on, the French also used the 3-arm Depillon semaphore at coastal locations to provide warning of British incursions. Many national services adopted signaling systems different from the Chappe system. For example, the UK and Sweden
Sweden
adopted systems of shuttered panels (in contradiction to the Chappe brothers' contention that angled rods are more visible). In Spain
Spain
, the engineer Agustín de Betancourt developed his own system which was adopted by that state. This system was considered by many experts in Europe better than Chappe's, even in France.

USE IN VARIOUS COUNTRIES

FRANCE

The Chappe Network in France
France

After Chappe's initial line (between Paris
Paris
and Lille), the Paris
Paris
to Strasbourg
Strasbourg
with 50 stations followed soon after (1798). By 1824, the Chappe brothers were promoting the semaphore lines for commercial use, especially to transmit the costs of commodities . Napoleon Bonaparte saw the military advantage in being able to transmit information between locations, and carried a portable semaphore with his headquarters. This allowed him to coordinate forces and logistics over longer distances than any other army of his time. However, because stations had to be within sight of each other, and because the efficient operation of the network required well trained and disciplined operators, the costs of administration and wages were a continuous source of financial difficulties. Only when the system was funded by the proceeds of its own lottery did costs come under control. A Chappe semaphore tower near Saverne , France
France

In 1821 Norwich Duff, a young British Naval officer, visiting Clermont-en-Argonne , walked up to the telegraph station there and engaged the signalman in conversation. Here is his note of the man's information:

The pay is twenty five sous per day and he is obliged to be there from day light till dark, at present from half past three till half past eight; there are only two of them and for every minute a signal is left without being answered they pay five sous: this is a part of the branch which communicates with Strasburg and a message arrives there from Paris
Paris
in six minutes it is here in four.

SWEDEN

A replica of an optical telegraph in Stockholm, Sweden
Sweden

At the same time as Chappe, the Swedish inventor Abraham Niclas Edelcrantz experimented with the optical telegraph in Sweden. In 1794 he inaugurated his telegraph with a poem dedicated to the Swedish King on his birthday. The message went from the Palace in Stockholm
Stockholm
to the King at Drottningholm . Edelcrantz eventually developed his own system which was quite different from its French counterpart and nearly twice as fast. The system was based on ten collapsible iron shutters. The various positions of the shutters formed combinations of numbers which were translated into letters, words or phrases via codebooks. The telegraph network consisted of telegraph stations positioned at about 10 kilometres (6.2 mi) from one another. Soon telegraph circuits linking castles and fortresses in the neighbourhood of Stockholm
Stockholm
were set up and the system was extended to Grisslehamn and Åland. Subsequently, telegraph circuits were introduced between Gothenburg and Marstrand, at Helsingborg and between Karlskrona and its fortresses. Sweden
Sweden
was the second country in the world, after France, to introduce an optical telegraph network. The Swedish optical telegraph network was restricted to the archipelagoes of Stockholm
Stockholm
, Gothenburg
Gothenburg
and Karlskrona . Like its French counterpart, it was mainly used for military purposes.

UNITED KINGDOM

Diagram of UK Murray six-shutter system, with shutter 6 in the horizontal position, and shutters 1-5 vertical

In Ireland
Ireland
, Richard Lovell Edgeworth returned to his earlier work in 1794, and proposed a telegraph there to warn against an anticipated French invasion; however, the proposal was not implemented. Lord George Murray , stimulated by reports of the Chappe semaphore, proposed a system of visual telegraphy to the British Admiralty in 1795. He employed rectangular framework towers with six, five feet high octagonal shutters on horizontal axes that flipped between horizontal and vertical positions to signal. The Rev. Mr Gamble also proposed two distinct five-element systems in 1795: one using five shutters, and one using five ten foot poles. The British Admiralty accepted Murray's system in September 1795, and the first system was the 15 site chain from London
London
to Deal . Messages passed from London to Deal in about sixty seconds, and sixty-five sites were in use by 1808. St. Albans
St. Albans
High Street in 1807, showing the shutter telegraph on top of the city's Clock Tower. It was on the London
London
to Great Yarmouth line

Chains of Murray's shutter telegraph stations were built along the following routes: London
London
—Deal and Sheerness , London—Great Yarmouth and London— Portsmouth
Portsmouth
and Plymouth
Plymouth
. The shutter stations were temporary wooden huts, and at the conclusion of the Napoleonic wars they were no longer necessary, and were closed down by the Admiralty in March 1816.

A replacement system was sought, and of the many ideas and devices put forward the Admiralty chose the simpler semaphore system invented by Sir Home Popham
Sir Home Popham
. A Popham semaphore was a single fixed vertical 30 foot pole, with two movable 8 foot arms attached to the pole by horizontal pivots at their ends, one arm at the top of the pole, and the other arm at the middle of the pole. The signals of the Popham semaphore were found to be much more visible than those of the Murray semaphore. Popham's 2-arm semaphore was modeled after the 3-arm Depillon French semaphore. An experimental semaphore line between the Admiralty and Chatham was installed in July 1816, and its success helped to confirm the choice.

Subsequently, the Admiralty decided to establish a permanent link to Portsmouth
Portsmouth
and built a chain of semaphore stations. Work started in December 1820 and the line was operational from 1822 until 1847, when the railway and electric telegraph provided a better means of communication. The semaphore line did not use the same locations as the shutter chain, but followed almost the same route with 15 stations - Admiralty (London), Chelsea Royal Hospital , Putney Heath , Coombe Warren , Coopers Hill , Chatley Heath , Pewley Hill , Bannicle Hill , Haste Hill ( Haslemere
Haslemere
), Holder Hill, (Midhurst) , Beacon Hill , Compton Down , Camp Down , Lumps Fort (Southsea), and Portsmouth Dockyard . The semaphore tower at Chatley Heath, which replaced the Netley Heath station of the shutter telegraph, has been restored by Surrey County Council and is open to the public.

The Board of Port of Liverpool obtained a Private Act of Parliament to construct a chain of Popham optical semaphore stations from Liverpool
Liverpool
Holyhead in 1825. A semaphore-based successor for the London
London
to Plymouth
Plymouth
shutter telegraph chain, branching much closer to London, at Chatley Heath in Surrey
Surrey
, was started but abandoned before completion. Many of the prominences on which the towers were built (telegraph hills ) are known as ' Telegraph
Telegraph
Hill' to this day. As in France
France
the network required lavish amounts of money and manpower to operate and could only be justified as a defence need.

OTHER COUNTRIES

Optical telegraph
Optical telegraph
in the harbour of Bremerhaven , Germany Former optical telegraph tower on the Winter Palace in Saint Petersburg , Russia
Russia

Once it had proved its success, the optical telegraph was imitated in many other countries, especially after it was used by Napoleon to coordinate his empire and army. In most of these countries, the postal authorities operated the semaphore lines.

In Portugal
Portugal
, the British forces fighting Napoleon in Portugal
Portugal
soon found that the Portuguese Army had already a very capable semaphore terrestrial system working since 1806, giving the Duke of Wellington a decisive advantage in intelligence. The innovative Portuguese telegraphs, designed by Francisco Ciera , a mathematician, were of 3 types: 3 shutters, 3 balls and 1 pointer/moveable arm (the first for longer distances, the other two for short) and with the advantage of all having only 6 significant positions. He also wrote the code book "Táboas Telegráphicas", with 1554 entries from 1 to 6666 (1 to 6, 11 to 16,... 61 to 66, 111 to 116,... etc.), the same for the 3 systems. Since early 1810 the network was operated by "Corpo Telegráfico", the first Portuguese military Signal Corps.

In Canada
Canada
, Prince Edward, Duke of Kent established the first semaphore line in North America. In operation by 1800, it ran between the city of Halifax and the town of Annapolis in Nova Scotia
Nova Scotia
, and across the Bay of Fundy to Saint John and Fredericton
Fredericton
in New Brunswick . In addition to providing information on approaching ships, the Duke used the system to relay military commands, especially as they related to troop discipline. The Duke had envisioned the line reaching as far as the British garrison at Quebec City
Quebec City
; however, the many hills and coastal fog meant the towers needed to be placed relatively close together to ensure visibility. The required labour to build and continually man so many stations taxed the already stretched-thin British military and there is doubt the New Brunswick line was ever in operation. With the exception of the towers around Halifax harbour, the system was abandoned shortly after the Duke's departure in August 1800. The Semaphore
Semaphore
Tower at Khatirbazar, Andul in Howrah district of West Bengal.

In 1801, the Danish post office installed a semaphore line across the Great Belt strait, Storebæltstelegrafen, between islands Funen and Zealand with stations at Nyborg
Nyborg
on Funen, on the small island Sprogø in the middle of the strait, and at Korsør
Korsør
on Zealand. It was in use until 1865.

The Kingdom of Prussia began with a line 750 kilometres (470 mi) long between Berlin
Berlin
and Coblenz in 1833, and in Russia
Russia
, Tsar Nicolas I inaugurated a line between Moscow
Moscow
and Warsaw
Warsaw
of 1,200 kilometres (750 mi) length in 1833; it needed 220 stations manned by 1,320 operators. Ta\' Kenuna Tower , a semaphore tower in Nadur , Gozo
Gozo
, Malta
Malta
, built by the British in 1848

The British military authorities began to consider installing a semaphore line in Malta
Malta
in the early 1840s. Initially, it was planned that semaphore stations be established on the bell towers and domes of the island's churches, but the religious authorities rejected the proposal. Due to this, in 1848 new semaphore towers were constructed at Għargħur and Għaxaq on the main island, and another was built at Ta\' Kenuna on Gozo. Further stations were established at the Governor\'s Palace , Selmun Palace
Selmun Palace
and the Giordan Lighthouse
Giordan Lighthouse
. Each station was manned by the Royal Engineers .

In the United States
United States
the first optical telegraph was built by Jonathan Grout . It was a 104 kilometres (65 mi) line connecting Martha\'s Vineyard with Boston
Boston
, and its purpose was to transmit news about shipping. One of the principal hills in San Francisco
San Francisco
, California
California
is also named " Telegraph
Telegraph
Hill ", after the semaphore telegraph which was established there in 1849 to signal the arrival of ships into San Francisco
San Francisco
Bay . The semaphores were successful enough that Samuel Morse
Samuel Morse
failed to sell the electrical telegraph to the French government; however, France
France
finally committed to replace semaphores with electric telegraphs in 1846. Electric telegraphs are both more private and almost completely unaffected by weather; they also work at night. Many contemporaries predicted the failure of electric telegraphs because "they are so easy to cut." The last stationary semaphore link in regular service was in Sweden, connecting an island with a mainland telegraph line. It went out of service in 1880.

IN POPULAR CULTURE

A cartoon strip of "Monsieur Pencil" (1831) by Rodolphe Töpffer

The Chappe telegraph appeared in contemporary fiction and comic strips. In "Mister Pencil" (1831), comic strip by Rodolphe Töpffer
Rodolphe Töpffer
, a dog fallen on a Chappe telegraph's arm and its master attempting to help provoke an international crisis by involuntarily transmitting disturbing messages. In " Lucien Leuwen
Lucien Leuwen
" (1834), Stendhal
Stendhal
pictures a power struggle between Lucien Leuwen
Lucien Leuwen
and the prefect M. de Séranville with the telegraph's director M. Lamorte. In Chapter 60 ("The Telegraph") of Alexandre Dumas
Alexandre Dumas
' The Count of Monte Cristo
The Count of Monte Cristo
(1844), the title character describes with fascination the semaphore line's moving arms. "I had at times seen rise at the end of a road, on a hillock and in the bright light of the sun, these black folding arms looking like the legs of an immense beetle." He later bribes a semaphore operator to relay a false message in order to manipulate the French financial market. Dumas also describes in details the functioning of a Chappe telegraph line. In Hector Malot 's novel Romain Kalbris (1869), one of the characters—a girl named Dielette, describes her home in Paris
Paris
as "...next to a church near which there was a clock tower. On top of the tower there were two large black arms, moving all day this way and that. that this was Saint-Eustache church and that these large black arms were a telegraph." The system was referenced in later works such as C. S. Forester
C. S. Forester
's Hornblower and the Hotspur (1962), where the destruction of a French semaphore tower and a shore battery is a key plot point. A similar event is also the focus of the seventh episode of the television series . Interference with the French semaphore system is also an important plot element in Ramage\'s Signal by Dudley Pope . In the young adult fiction book Death Cloud by Andy Lane (2010), Mycroft Holmes tells 14-year-old Sherlock Holmes
Sherlock Holmes
about semaphore stations, commenting about his school beforehand, saying "All the Latin a boy can cram into his skull, but nothing of practical use."

Fictional versions of the telegraph also appear in literature. In the alternative history novel, Lest Darkness Fall (1939), by L. Sprague de Camp , the protagonist, a twentieth century man who time travels into Dark Age Rome
Rome
, develops a semaphore system to warn of invasion. To make it practical, he also invents the telescope . Pavane (1968), an alternate history novel by Keith Roberts , features a society where long distance communication is by a network of semaphores operated by the powerful Guild of Signallers. Terry Pratchett's Discworld novels (from The Fifth Elephant , 1999, onwards) describe a system of eight-shutter semaphore towers, known as Clacks , which occupy a similar role to that of the Internet
Internet
. Using advanced clack coding, it is possible not only to send very fast telegrams, but also to encode pictures and send them long-distance, and shopping and banking via the clacks is also mentioned. In David Weber 's Safehold series (2007), a worldwide semaphore system is used by the Church to help them maintain their dominion over the world. In Alastair Reynolds
Alastair Reynolds
' Terminal World (2010), the distant-future terrain is criss-crossed with semaphore lines relaying information between the one remaining city, Spearpoint, outlying communities and the airborne community Swarm.

SEE ALSO

* History of telecommunication
History of telecommunication
* Optical communication * Railway signalling * Semaphore Flag Signaling System * Signal lamp * Telegraph
Telegraph
Hill , for a list of telegraph hills

REFERENCES

Citations

* ^ A B C D E Chapter 2: Semaphore
Semaphore
Signalling ISBN 978-0-86341-327-8 Communications: an international history of the formative years R. W. Burns, 2004 * ^ A B C Telegraph
Telegraph
Vol 10, Encyclopædia Britannica, 6th Edition, 1824 pp. 645–651 * ^ A B C D Telegraph, Volume 17 of The Edinburgh Encyclopaedia, pp. 664–667, 1832 David Brewster, ed. * ^ Groundbreaking Scientific Experiments, Inventions & Discoveries of the 18th Century, Jonathan Shectman, p. 172 * ^ Oxford English Dictionary. * ^ Webster's Unabridged Dictionary. * ^ 500 Years of New Words, Bill Sherk * ^ "The Origin of the Railway Semaphore". Mysite.du.edu. Retrieved 2013-06-17. * ^ "History of the Telephone part2". Ilt.columbia.edu. Retrieved 2013-06-17. * ^ Rees, Abraham , ed. (1802–1820). "Telegraph". Cyclopædia. 35. London: Longman, Hurst, Rees, Orme & Brown. Unpaginated work: pages 9-11 of the article entry. * ^ Burns, Francis W. (2004). Communications: An International History of the Formative Years. IET. Retrieved 2013-02-07. * ^ How Napoleon\'s semaphore telegraph changed the world, BBC News, Hugh Schofield, 16 June 2013 * ^ http://www.ieeeghn.org/wiki/images/1/17/Dilhac.pdf * ^ Holzmann, Gerard J.; Pehrson, Bjorn (2003). The Early History of Data Networks. * ^ http://web.archive.org/web/20140202183712/http://chappe.ec-lyon.fr/message.html * ^ Lieutenant Watson\'s Telegraph
Telegraph
Mechanics' magazine, Volume 8 No. 222, Knight and Lacey, 1828, pages 294-299 * ^ A B F.B. Wrixon (2005), ISBN 978-1-57912-485-4 Codes, Ciphers, Secrets and Cryptic Communication pp. 444-445 cover Murray's shutter telegraph in the U.K., with codes. * ^ A B * ^ A B C Military Signals from the South Coast, John Goodwin, 2000 * ^ Faster Than The Wind, The Liverpool
Liverpool
to Holyhead Telegraph, Frank Large, an avid publication ISBN 0-9521020-9-9 * ^ Raddall, Thomas H. (1971), Warden of the North, Toronto, Canada: McClelland and Stewart Limited * ^ Rens, Jean-Guy (2001), The invisible empire: A history of the telecommunications industry in Canada, Montreal, Canada: McGill-Queen's University Press * ^ The Age of Invention 1849–1920, Post & Tele Museum Danmark, website visited on May 8, 2010. * ^ " Semaphore
Semaphore
Tower". Għargħur Local Council. Archived from the original on 4 March 2016. * ^ Holzmann, Gerard. "Data Communications: The First 2,500 Years" (PDF). Retrieved 28 June 2011. * ^ Page 84 in * ^ See second paragraph in

Bibliography

* Crowley, David and Heyer, Paul (ed) (2003) 'Chapter 17: The optical telegraph' Communication in History: Technology, Culture and Society (Fourth Edition) Allyn and Bacon, Boston
Boston
pp. 123–125

FURTHER READING

* The Victorian Internet, Tom Standage, Walker & Company, 1998, ISBN 0-8027-1342-4 * The Old Telegraphs, Geoffrey Wilson, Phillimore ;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none;">v

* t * e

Free-space optical communication

FOUNDATIONS AND GENERAL CONCEPTS

* Optical wireless communications * Optical communication * Wireless LAN

TERRESTRIAL, VISIBLE LIGHT COMMUNICATION

* Li-Fi * Semaphore
Semaphore
line * Visible light communication * ...

TERRESTRIAL, IR COMMUNICATION

* Consumer IR * ...

TERRESTRIAL, UV COMMUNICATION

* Optical Spectrum Analyzer * ...

OUTER SPACE COMMUNICATION

* Optical Satellite Networks * Communications satellite * ...

* v * t * e

Types of writing systems

OVERVIEW

* History of writing * Grapheme

LISTS

* Writing systems

* undeciphered * inventors * constructed

* Languages by writing system / by first written accounts

TYPES

ABJADS

* Numerals

* Aramaic

* Hatran

* Arabic * Pitman shorthand
Pitman shorthand

* Hebrew

* Ashuri * Cursive * Rashi * Solitreo

* Tifinagh * Manichaean * Nabataean * Old North Arabian * Pahlavi * Pegon

* Phoenician

* Paleo-Hebrew

* Proto-Sinaitic * Psalter * Punic * Samaritan

* South Arabian

* Zabur * Musnad

* Sogdian

* Syriac

* ʾEsṭrangēlā * Serṭā * Maḏnḥāyā

* Teeline Shorthand
Teeline Shorthand
* Ugaritic

ABUGIDAS

BRAHMIC

NORTHERN

* Asamiya (Ôxômiya) * Bānglā * Bhaikshuki * Bhujinmol * Brāhmī * Devanāgarī * Dogri * Gujarati * Gupta * Gurmukhī * Kaithi * Kalinga * Khojki * Khotanese * Khudawadi * Laṇḍā * Lepcha * Limbu * Mahajani * Meitei Mayek * Modi * Multani * Nāgarī * Nandinagari * Odia * \'Phags-pa * Newar * Ranjana * Sharada * Saurashtra * Siddhaṃ * Soyombo * Sylheti Nagari * Takri

* Tibetan

* Uchen * Umê

* Tirhuta * Tocharian * Zanabazar Square

* Zhang-Zhung

* Drusha * Marchen * Marchung * Pungs-chen * Pungs-chung

SOUTHERN

* Ahom * Balinese * Batak * Baybayin
Baybayin
* Bhattiprolu * Buhid * Burmese * Chakma * Cham * Grantha * Goykanadi * Hanunó\'o * Javanese * Kadamba * Kannada * Kawi * Khmer * Kulitan * Lanna * Lao * Leke * Lontara * Malayalam

* Maldivian

* Dhives Akuru * Eveyla Akuru * Thaana

* Mon * Old Makassarese * Old Sundanese * Pallava * Pyu * Rejang * Rencong * Sinhala * Sundanese * Tagbanwa * Tai Le * Tai Tham * Tai Viet * Tamil * Telugu * Thai * Tigalari

* Vatteluttu

* Kolezhuthu * Malayanma

* Visayan

OTHERS

* Boyd\'s syllabic shorthand

* Canadian syllabics

* Blackfoot * Déné syllabics
Déné syllabics

* Fox I * Ge\'ez * Gunjala Gondi * Japanese Braille
Japanese Braille
* Jenticha * Kayah Li * Kharosthi
Kharosthi
* Mandombe * Masaram Gondi * Meroitic * Miao * Mwangwego * Sorang Sompeng * Pahawh Hmong * Thomas Natural Shorthand
Thomas Natural Shorthand

ALPHABETS

LINEAR

* Abkhaz * Adlam * Armenian * Avestan * Avoiuli
Avoiuli
* Bassa Vah * Borama * Carian * Caucasian Albanian * Coorgi–Cox alphabet
Coorgi–Cox alphabet
* Coptic * Cyrillic * Deseret

* Duployan shorthand
Duployan shorthand

* Chinook writing

* Early Cyrillic * Eclectic shorthand
Eclectic shorthand
* Elbasan * Etruscan * Evenki * Fox II * Fraser * Gabelsberger shorthand
Gabelsberger shorthand
* Garay

* Georgian

* Asomtavruli
Asomtavruli
* Nuskhuri
Nuskhuri
* Mkhedruli
Mkhedruli

* Glagolitic * Gothic * Gregg shorthand
Gregg shorthand
* Greek * Greco-Iberian alphabet * Hangul * Hanifi * IPA * Kaddare

* Latin

* Beneventan * Blackletter * Carolingian minuscule * Fraktur
Fraktur
* Gaelic * Insular * Kurrent * Merovingian * Sigla * Sütterlin
Sütterlin
* Tironian notes
Tironian notes
* Visigothic

* Luo * Lycian * Lydian * Manchu * Mandaic * Medefaidrin * Molodtsov * Mongolian * Mru * Neo- Tifinagh * New Tai Lue * N\'Ko * Ogham
Ogham
* Oirat * Ol Chiki * Old Hungarian * Old Italic * Old Permic * Orkhon * Old Uyghur * Osage * Osmanya * Pau Cin Hau

* Runic

* Anglo-Saxon * Cipher * Dalecarlian * Elder Futhark
Elder Futhark
* Younger Futhark * Gothic * Marcomannic * Medieval * Staveless

* Sidetic * Shavian * Somali * Tifinagh * Vagindra * Visible Speech
Visible Speech
* Vithkuqi * Wancho * Zaghawa

NON-LINEAR

* Braille
Braille
* Maritime flags * Morse code
Morse code
* New York Point * Semaphore
Semaphore
line * Flag semaphore * Moon type
Moon type

IDEOGRAMS /PICTOGRAMS

* Adinkra * Aztec * Blissymbol * Dongba * Ersu Shaba * Emoji * IConji * Isotype * Kaidā * Míkmaq * Mixtec * New Epoch Notation Painting
New Epoch Notation Painting
* Nsibidi
Nsibidi
* Ojibwe Hieroglyphs * Siglas poveiras
Siglas poveiras
* Testerian
Testerian
* Yerkish * Zapotec

LOGOGRAMS

CHINESE FAMILY OF SCRIPTS

CHINESE CHARACTERS

* Simplified * Traditional * Oracle bone script * Bronze Script

* Seal Script

* large * small * bird-worm

* Hanja
Hanja
* Idu * Kanji * Chữ nôm * Zhuang

CHINESE-INFLUENCED

* Jurchen * Khitan large script
Khitan large script
* Sui * Tangut

CUNEIFORM

* Akkadian * Assyrian * Elamite * Hittite * Luwian * Sumerian

OTHER LOGO-SYLLABIC

* Anatolian * Bagam * Cretan * Isthmian * Maya * Proto-Elamite * Yi (Classical)

LOGO-CONSONANTAL

* Demotic * Hieratic * Hieroglyphs

NUMERALS

* Hindu-Arabic * Abjad * Attic (Greek) * Muisca * Roman

SEMI-SYLLABARIES

FULL

* Celtiberian * Northeastern Iberian * Southeastern Iberian * Khom

REDUNDANT

* Espanca * Pahawh Hmong * Khitan small script
Khitan small script
* Southwest Paleohispanic * Zhuyin fuhao

SOMACHEIROGRAMS

* ASLwrite * SignWriting
SignWriting
* si5s * Stokoe Notation

SYLLABARIES

* Afaka * Bamum * Bété * Byblos * Cherokee * Cypriot * Cypro-Minoan * Ditema tsa Dinoko * Eskayan * Geba * Great Lakes Algonquian syllabics * Iban

* Japanese

* Hiragana
Hiragana
* Katakana * Man\'yōgana * Hentaigana
Hentaigana
* Sogana
Sogana
* Jindai moji
Jindai moji

* Kikakui * Kpelle * Linear B * Linear Elamite
Linear Elamite
* Lisu * Loma * Nüshu * Nwagu Aneke script * Old Persian Cuneiform * Vai * Woleai * Yi (Modern) * Yugtun

* v * t * e

Braille
Braille
⠃⠗⠁⠊⠇⠇⠑

BRAILLE CELL

* 1829 braille
1829 braille
* International uniformity * ASCII braille * Unicode braille patterns

BRAILLE SCRIPTS

French-ordered scripts (see for more)

* Albanian * Amharic * Arabic * Armenian * Azerbaijani * Belarusian

* Bharati

* Devanagari (Hindi / Marathi / Nepali) * Bengali * Punjabi * Sinhalese * Tamil * Urdu * etc.

* Bulgarian * Burmese * Cambodian * Cantonese * Catalan * Chinese (Mandarin, mainland) * Czech * Dutch * Dzongkha (Bhutanese) * English (Unified English ) * Esperanto * Estonian * Faroese * French * Georgian * German * Ghanaian * Greek * Guarani * Hawaiian * Hebrew * Hungarian * Icelandic * Inuktitut (reassigned vowels) * Iñupiaq * IPA * Irish * Italian * Kazakh * Kyrgyz * Latvian * Lithuanian * Maltese * Mongolian * Māori * Nigerian * Northern Sami * Persian * Philippine * Polish * Portuguese * Romanian * Russian * Samoan * Scandinavian * Slovak * South African * Spanish * Tatar * Taiwanese Mandarin (largely reassigned) * Thai border-left-width:2px;border-left-style:solid;width:100%;padding:0px">

* Algerian Braille
Braille
(obsolete)

FREQUENCY-BASED SCRIPTS

* American Braille
Braille
(obsolete)

INDEPENDENT SCRIPTS

* Japanese * Korean * Two-Cell Chinese

EIGHT-DOT SCRIPTS

* Luxembourgish * Kanji * Gardner–Salinas braille codes (GS8)

SYMBOLS IN BRAILLE

* Braille
Braille
music * Canadian currency marks * Computer Braille
Braille
Code
Code
* Gardner–Salinas braille codes (GS8/GS6) * International Phonetic Alphabet (IPA) * Nemeth braille code

BRAILLE TECHNOLOGY

* Braille
Braille
e-book * Braille
Braille
embosser * Braille
Braille
translator * Braille
Braille
watch * Mountbatten Brailler * Optical braille recognition
Optical braille recognition
* Perforation * Perkins Brailler
Perkins Brailler
* Refreshable braille display
Refreshable braille display
* Slate and stylus
Slate and stylus
* Braigo
Braigo

PERSONS

* Louis Braille
Braille
* Charles Barbier * Valentin Haüy
Valentin Haüy
* Thakur Vishva Narain Singh * Sabriye Tenberken * William Bell Wait
William Bell Wait

ORGANISATIONS

* Braille
Braille
Institute of America * Braille
Braille
Without Borders * Japan Braille
Braille
Library * National Braille
Braille
Association * Blindness organizations * Schools for the blind * American Printing House for the Blind

OTHER TACTILE ALPHABETS

* Decapoint
Decapoint
* Moon type
Moon type
* New York Point * Night writing
Night writing
* Vibratese

RELATED TOPICS

* Accessible publishing * Braille
Braille
literacy * Robo Braille
Braille

* v * t * e

Telecommunications

HISTORY

* Beacon * Broadcasting * Cable protection system * Cable TV * Communications satellite * Computer network * Drums * Electrical telegraph * Fax * Heliographs * Hydraulic telegraph
Hydraulic telegraph
* Internet
Internet
* Mass media * Mobile phone * Optical telecommunication * Optical telegraphy * Pager * Photophone * Prepaid mobile phone * Radio * Radiotelephone * Satellite communications * Semaphore
Semaphore
* Smartphone
Smartphone
* Smoke signals * Telecommunications history * Telautograph
Telautograph
* Telegraphy * Teleprinter (teletype) * Telephone * The Telephone Cases * Television * Timeline of communication technology * Undersea telegraph line * Videoconferencing * Videophone * Videotelephony * Whistled language

PIONEERS

* Edwin Howard Armstrong
Edwin Howard Armstrong
* John Logie Baird * Paul Baran
Paul Baran
* Alexander Graham Bell
Alexander Graham Bell
* Tim Berners-Lee * Jagadish Chandra Bose * Vint Cerf * Claude Chappe * Donald Davies * Lee de Forest * Philo Farnsworth * Reginald Fessenden * Elisha Gray
Elisha Gray
* Erna Schneider Hoover
Erna Schneider Hoover
* Charles K. Kao * Hedy Lamarr * Innocenzo Manzetti * Guglielmo Marconi
Guglielmo Marconi
* Antonio Meucci
Antonio Meucci
* Radia Perlman * Alexander Stepanovich Popov * Johann Philipp Reis * Nikola Tesla * Camille Tissot
Camille Tissot
* Alfred Vail
Alfred Vail
* Charles Wheatstone
Charles Wheatstone
* Vladimir K. Zworykin
Vladimir K. Zworykin

Transmission media

* Coaxial cable
Coaxial cable
* Free-space optical communication * Molecular communication * Optical fiber * Radio waves * Transmission line
Transmission line

Network topology and switching

* Links * Nodes * Terminal node * Network switching (circuit * packet ) * Telephone exchange
Telephone exchange

MULTIPLEXING

* Space-division * Frequency-division * Time-division * Polarization-division * Orbital angular-momentum * Code-division

NETWORKS

* ARPANET * BITNET * Cellular network * Computer * CYCLADES
CYCLADES
* Ethernet * FidoNet * Internet
Internet
* ISDN * LAN * Mobile * NGN * NPL network * Public Switched Telephone * Radio * Telecommunications equipment * Television * Telex
Telex
* WAN * Wireless * World Wide Web

*