Electrical telegraph and Related Topics

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

Telegraphy

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Long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message.

Schematic of a Prussian optical telegraph (or semaphore) tower, c. 1835

19th-century demonstration of the semaphore

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

An early Cooke and Wheatstone double-needle railway telegraph instrument at the National Railway Museum

A block signalling instrument as used in Britain in the 20th century

Australian troops using a Mance mk.V heliograph in the Western Desert in November 1940

US Forest Service lookout using a Colomb shutter type heliograph in 1912 at the end of a telephone line

Creed paper tape reader at The National Museum of Computing

The first message is received by the Submarine Telegraph Company in London from Paris on the Foy–Breguet instrument in 1851. The equipment in the background is a Cooke and Wheatstone set for onward transmission.

The Eastern Telegraph Company network in 1901

Alexander Bain's facsimile machine, 1850

Marconi watching associates raising the kite (a "Levitor" by B.F.S. Baden-Powell ) used to lift the antenna at St. John's, Newfoundland, December 1901

Post Office Engineers inspect the Marconi Company's equipment at Flat Holm, May 1897

ITT Creed Model 23B teleprinter with telex dial-up facility

An illustration declaring that the submarine cable between England and France would bring those countries peace and goodwill

The electric telegraph started to replace the optical telegraph in the mid-19th century.

Morse code

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Method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs.

This Morse key was originally used by Gotthard railway, later by a shortwave radio amateur

Telegraph key and sounder. The signal is "on" when the knob is pressed, and "off" when it is released. Length and timing of the dits and dahs are entirely controlled by the telegraphist.

Morse code receiver, recording on paper tape

Comparison of historical versions of Morse code with the current standard. Left: Later American Morse code from 1844. Center: The modified and rationalized version used by Friedrich Gerke on German railways. Right: Current ITU standard.

A U.S. Navy Morse Code training class in 2015. The sailors will use their new skills to collect signals intelligence.

A commercially manufactured iambic paddle used in conjunction with an electronic keyer to generate high-speed Morse code, the timing of which is controlled by the electronic keyer.

A U.S. Navy signalman sends Morse code signals in 2005.

Graphical representation of the dichotomic search table. The graph branches left for each dot and right for each dash until the character representation is exhausted.

Scout movement founder Baden-Powell's mnemonic chart from 1918

Morse code is named after Samuel Morse, one of the inventors of the telegraph.

Samuel Morse

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American inventor and painter.

Birthplace of Morse, Charlestown, Massachusetts, c. 1898 photo

Daguerreotype of Samuel Morse Professor of Art while at NYU in 1839. One of the earliest existing American photographs by Dr John William Draper

Self-portrait of Morse in 1812 (National Portrait Gallery)

Dying Hercules, Morse's early masterpiece

Jonas Platt, New York politician, by Morse. Oil on canvas, 1828, Brooklyn Museum.

The House of Representatives. Oil on canvass, 1822, National Gallery of Art.

Morse maintained a studio at 94 Tradd St., Charleston, South Carolina, for a short period.

Leonard Gale, who helped Morse achieve the technological breakthrough of getting the telegraphic signal to travel long distances over wire

Cover of Foreign Conspiracy Against the Liberties of the United States by Samuel F.B. Morse, 1835 edition

Morse's "repeater" circuit for telegraphy was the basis for the Supreme Court's holding some claims of Morse's patent valid.

Portrait of Samuel F. B. Morse taken by Mathew Brady, in 1866. Medals worn (from wearer's right to left, top row): Nichan Iftikhar (Ottoman); Order of the Tower and Sword (Portugal); Order of the Dannebrog (Denmark); cross of the Order of Isabella the Catholic (Spain); Legion of Honour (France); Order of Saints Maurice and Lazarus (Italy). Bottom row: Grand cross of the Order of Isabella the Catholic (Spain)

Statue of Samuel F. B. Morse by Byron M. Picket, New York's Central Park, dedicated 1871

Morse was honored on the US Famous Americans Series postal issue of 1940.

Captain Demaresque of Gloucester, Massachusetts, Princeton University Art Museum

Portrait of James Monroe, 5th President of the United States (c. 1819)

Eli Whitney, inventor, 1822. Yale University Art Gallery

Chart of Colors, drawn to illustrate his palette of colors

After having established his reputation as a portrait painter, in his middle age Morse contributed to the invention of a single-wire telegraph system based on European telegraphs.

Wheatstone, drawn by Samuel Laurence in 1868

English scientist and inventor of many scientific breakthroughs of the Victorian era, including the English concertina, the stereoscope (a device for displaying three-dimensional images), and the Playfair cipher ( an encryption technique).

Michael Faraday, T. H. Huxley, Wheatstone, David Brewster, and John Tyndall (r.)

A double-needle telegraph instrument of the type used on the Great Western Railway

Francis Ronalds had observed signal retardation in his buried electric telegraph cable (but not his airborne line) in 1816 and outlined its cause to be induction.

Cooke and Wheatstone's two-needle telegraph as used on the Great Western Railway

Cooke and Wheatstone telegraph

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Cooke and Wheatstone's five-needle, six-wire telegraph

Cooke and Wheatstone 5-wire telegraph cable in a wooden spacer

Five-needle telegraph receiving the letter G.

Circuit diagram of the five-needle telegraph transmitting the character A

Original codes for the one-, two-, and five-needle telegraphs. A stroke leaning to the left indicates a needle rotated anti-clockwise, that is, with the top pointing to the left. A stroke leaning to the right indicates a needle pointing to the right. For multiple stroke codes, the first movement is in the direction of the short stroke. For example, in the one-needle code, E is left-right-left, L is right-left-right-left, and U is left-left-right.

The Cooke and Wheatstone telegraph was an early electrical telegraph system dating from the 1830s invented by English inventor William Fothergill Cooke and English scientist Charles Wheatstone.

A replica of one of Chappe's semaphore towers in Nalbach, Germany

Optical telegraph

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Line of stations, typically towers, for the purpose of conveying textual information by means of visual signals.

Illustration of signalling by semaphore in 18th-century France. The operators would move the semaphore arms to successive positions to spell out text messages in semaphore code, and the people in the next tower would read them.

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.

Sir Richard Lovell Edgeworth's proposed optical telegraph for use in Ireland. The rotational position of each one of the four indicators represented a number 1-7 (0 being "rest"), forming a four-digit number. The number stood for a particular word in a codebook.

A Chappe semaphore tower near Saverne, France

A replica of an optical telegraph in Stockholm, Sweden

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

St. Albans High Street in 1807, showing the shutter telegraph on top of the city's Clock Tower. It was on the London to Great Yarmouth line.

Ta' Kenuna Tower, a semaphore tower in Nadur, Gozo, Malta, built by the British in 1848

The Semaphore Tower at Khatirbazar, Andul in Howrah district of West Bengal

A restored two-arm semaphore post at Low Head in Tasmania

The vane positions indicate code numbers

Optical telegraph in the harbour of Bremerhaven, Germany

Former optical telegraph tower on the Winter Palace in Saint Petersburg, Russia

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

Half a century later, semaphore lines were replaced by the electrical telegraph, which was cheaper, faster, and more private.

Needle telegraph

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Cooke and Wheatstone five-needle telegraph

A needle telegraph is an electrical telegraph that uses indicating needles moved electromagnetically as its means of displaying messages.

Earth station at the satellite communication facility in Raisting, Bavaria, Germany

Telecommunications

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Transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems.

Visualization from the Opte Project of the various routes through a portion of the Internet

A replica of one of Chappe's semaphore towers

Optical fiber provides cheaper bandwidth for long-distance communication.

Digital television standards and their adoption worldwide

20th- and 21st-century technologies for long-distance communication usually involve electrical and electromagnetic technologies, such as telegraph, telephone, television and teleprinter, networks, radio, microwave transmission, optical fiber, and communications satellites.