A telegraph is a machine for transmitting and receiving messages over long distances, i.e., for telegraphy. The word telegraph alone now generally refers to an electrical telegraph. Wireless telegraphy is also known as CW, for continuous wave (a carrier modulated by on-off keying), as opposed to the earlier radio technique using a spark gap.Fact: date=September 2008

A telegraph message sent by a telegraph operator (or telegrapher) using Morse code was known as a telegram or cablegram, often shortened to a cable or a wire message. Later, a telegram sent by the Telex network, a switched network of teleprinters similar to the telephone network, was known as a telex message.

Before long distance telephone services were readily available or affordable, telegram services were very popular. Telegrams were often used to confirm business dealings and, unlike email, telegrams were commonly used to create binding legal documents for business dealings.Fact: date=September 2008

A wire picture or wire photo was a newspaper picture that was sent from a remote location by a facsimile telegraph.

Optical

The first telegraphs came in the form of optical telegraphs, including the use of smoke signals and beacons, which have existed since ancient times. A semaphore network invented by Claude Chappe operated in France from 1792 through 1846. It helped Napoleon enough to be widely imitated in Europe and the U.S. The last commercial semaphore link ceased operation in Sweden in 1880.

Semaphores were able to convey information more precisely than smoke signals and beacons, and consumed no fuel. Messages could be sent at much greater speed than post riders and could serve entire regions. However, like beacons and smoke signals, they were dependent on good weather to work. They required operators and towers every 30 km (20 mi), and could only accommodate about two words per minute. This was useful to governments, but too expensive for most commercial uses other than commodity price information. Electric telegraphs were to reduce the cost of sending a message thirtyfold compared to semaphores.

Some elevated locations where optical telegraphs were placed for maximum visibility were renamed to Telegraph Hill, such as Telegraph Hill, San Francisco, and Telegraph Hill in the PNC Bank Arts Center in New Jersey. To people who are only aware of the electrical telegraph, the reason for this name will be obscure.

Electrical telegraphs

Main: Electrical telegraph Samuel Thomas von Sömmering constructed his electrochemical telegraph in 1809. Also as one of the first, an electromagnetic telegraph was created by Baron Schilling in 1832. Carl Friedrich Gauss and Wilhelm Weber built and first used for regular communication the electromagnetic telegraph in 1833 in Göttingen. The first commercial electrical telegraph was constructed by Sir William Fothergill Cooke and entered use on the Great Western Railway in Britain. It ran for from Paddington station to West Drayton and came into operation on 9 April 1839. It was patented in the United Kingdom in 1837. In 1843 Scottish inventor Alexander Bain invented a device that could be considered the first facsimile machine. He called his invention a "recording telegraph". Bain's telegraph was able to transmit images by electrical wires. In 1855 an Italian abbot, Giovanni Caselli, also created an electric telegraph that could transmit images. Caselli called his invention "Pantelegraph". Pantelegraph was successfully tested and approved for a telegraph line between Paris and Lyon.