Telegraph Key

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Description (Brief)
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
Currently not on view
Physical Description
wood (switch base material)
brass (overall material)
metal (overall material)
rubber (overall material)
overall: 1 1/4 in x 11 in x 9 in; 3.175 cm x 27.94 cm x 22.86 cm
ID Number
catalog number
accession number
Credit Line
from the French Cable Company
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Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History


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