Telegraph Key

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.
Location
Currently not on view
Object Name
cable key
telegraph key
submarine telegraph key
date made
ca 1890
maker
Foote, Pierson & Co.
Physical Description
slate (overall material)
brass (overall material)
Measurements
overall: 2 1/2 in x 4 1/2 in x 6 1/4 in; 6.35 cm x 11.43 cm x 15.875 cm
ID Number
EM.329942
accession number
283729
catalog number
329942
Credit Line
from Western Union International
subject
Telegraph
See more items in
Work and Industry: Electricity
Telegraph Keys
Communications
Data Source
National Museum of American History
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