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Many electrical telegraph systems were invented that operated in different ways, but the ones that became widespread fit into two broad categories. First are the needle telegraphs, in which electric current sent down the telegraph line produces electromagnetic force to move a needle-shaped pointer into position over a printed list.
Both electrostatic and electromagnetic induction were used to develop wireless telegraph systems that saw limited commercial application. In the United States, Thomas Edison , in the mid-1880s, patented an electromagnetic induction system he called "grasshopper telegraphy", which allowed telegraphic signals to jump the short distance between a ...
A single needle telegraph (1903) A needle telegraph is an electrical telegraph that uses indicating needles moved electromagnetically as its means of displaying messages. It is one of the two main types of electromagnetic telegraph, the other being the armature system, [1] as exemplified by the telegraph of Samuel Morse in the United States.
Earth-return telegraph is the system whereby the return path for the electric current of a telegraph circuit is provided by connection to the earth through an earth electrode. Using earth return saves a great deal of money on installation costs since it halves the amount of wire that is required, with a corresponding saving on the labour ...
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. It was a form of needle telegraph, and the first telegraph system to be put into commercial service. The receiver consisted of a number of needles that ...
1832 – Baron Pavel L'vovitch Schilling (Paul Schilling) creates the first electromagnetic telegraph, consisting of a single-needle system in which a code was used to indicate the characters. Only months later, Göttingen professors Carl Friedrich Gauss and Wilhelm Weber constructed a telegraph that was working two years before Schilling could ...
The Speedwell Ironworks, site of Morse's 1838 telegraph demonstration. Samuel Morse in 1845. 1826-27: Harrison Gray Dyar successfully experiments with electrical telegraphy but abandons the pursuit. 1836: David Alter of Pennsylvania develops a working electrical telegraph system, but never develops the idea into a practical system.
Efforts to find a way to transmit telegraph signals without wires grew out of the success of electric telegraph networks, the first instant telecommunication systems. [23] Developed beginning in the 1830s, a telegraph line was a person-to-person text message system consisting of multiple telegraph offices linked by an overhead wire supported on ...