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Telegraphy is the 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. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in ...
The telegraph represented a disruptive innovation in the history of the United States from its invention in the 1830s onward by quickly becoming a vital part of the nation's communication infrastructure. Its relative importance declined with the spread of telephones in the 20th century. Telegraph service permitted short texts to be sent cheaply ...
Gray had filed his caveat for the variable resistance telephone, but Bell was the first to document the idea and test it in a telephone.[88] [22] Antonio Meucci invented a device that allowed the electrical transmission of voice over a line nearly 30 years before in 1849, but his device was of little practical value because it relied on the ...
The telephone played a major communications role in American history from the 1876 publication of its first patent by Alexander Graham Bell onward. In the 20th century the American Telephone and Telegraph Company (AT&T) dominated the telecommunication market as the at times largest company in the world, until it was broken up and replaced by a ...
Hughes telegraph, an early (1855) teleprinter built by Siemens and Halske. Electrical telegraphy is a point-to-point text messaging system, primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications system and the most widely used of a number of early messaging systems called telegraphs, that were ...
The history of telecommunication began with the use of smoke signals and drums in Africa, Asia, and the Americas. In the 1790s, the first fixed semaphore systems emerged in Europe. However, it was not until the 1830s that electrical telecommunication systems started to appear. This article details the history of telecommunication and the ...
Wireless telegraphy or radiotelegraphy is the transmission of text messages by radio waves, analogous to electrical telegraphy using cables. [1][2] Before about 1910, the term wireless telegraphy was also used for other experimental technologies for transmitting telegraph signals without wires. [3][4] In radiotelegraphy, information is ...
An old rotary dial telephone. AT&T push button telephone made by Western Electric, model 2500 DMG black, 1980. A telephone, colloquially referred to as a phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically ...