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
telegraph key
submarine telegraph key
maker
O. & F. H. Varley
Physical Description
brass (overall material)
metal (overall material)
plastic (overall material)
Measurements
overall: 2 3/4 in x 3 5/8 in x 6 1/8 in; 6.985 cm x 9.2075 cm x 15.5575 cm
ID Number
EM.332225
collector/donor number
100-692
accession number
294351
catalog number
332225
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Communications
Telegraph Keys
Data Source
National Museum of American History
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