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Telegraphy (from Greek: τῆλε ''têle'', "at a distance" and γράφειν ''gráphein'', "to write") is the long-distance transmission of textual or symbolic (as opposed to verbal or audio) messages without the physical exchange of an object bearing the message. Thus semaphore is a method of telegraphy, whereas pigeon post is not. Telegraphy requires that the method used for encoding the message be known to both sender and receiver. Such methods are designed according to the limits of the signalling medium used. The use of smoke signals, beacons, reflected light signals, and flag semaphore signals are early examples. In the 19th century, the harnessing of electricity led to the invention of electrical telegraphy. The advent of radio in the early 1900s brought about radiotelegraphy and other forms of wireless telegraphy. In the Internet age, telegraphic means developed greatly in sophistication and ease of use, with natural language interfaces that hide the underlying code, allowing such technologies as electronic mail and instant messaging. ==Terminology== The word "telegraph" was first coined by the French inventor of the Semaphore line, Claude Chappe, who also coined the word "semaphore".〔Groundbreaking Scientific Experiments, Inventions & Discoveries of the 18th Century, Jonathan Shectman, p172〕 A "telegraph" is a device 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 of using a spark gap. Contrary to the extensive definition used by Chappe, Morse argued that the term ''telegraph'' can strictly be applied only to systems that transmit ''and'' record messages at a distance. This is to be distinguished from ''semaphore'', which merely transmits messages. Smoke signals, for instance, are to be considered semaphore, not telegraph. According to Morse, telegraph dates only from 1832, when Pavel Schilling invented one of the earliest electrical telegraphs.〔Samuel F. B. Morse, (''Examination of the Telegraphic Apparatus and the Processes in Telegraphy'' ), pages 7-8, Philp & Solomons 1869 .〕 A telegraph message sent by an electrical telegraph operator or telegrapher using Morse code (or a printing telegraph operator using plain text) was known as a ''telegram''. A ''cablegram'' was a message sent by a submarine telegraph cable,〔(【引用サイトリンク】title=Cablegram - Definition of cablegram by Merriam-Webster )〕 often shortened to a ''cable'' or a ''wire''. Later, a ''Telex'' was a message sent by a Telex network, a switched network of teleprinters similar to a telephone network. A ''wire picture'' or ''wire photo'' was a newspaper picture that was sent from a remote location by a facsimile telegraph. A ''diplomatic telegram'', also known as a diplomatic cable, is the term given to a confidential communication between a diplomatic mission and the foreign ministry of its parent country.〔Definition of "cable", 〕 These continue to be called telegrams or cables regardless of the method used for transmission. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「telegraphy」の詳細全文を読む スポンサード リンク
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