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. This particular key was used in testing insulation at Tufts University in the years around 1910.
Currently not on view
date made
ca 1890
ca 1903
Queen and Company
Physical Description
plastic (overall material)
brass (overall material)
overall: 3 3/4 in x 4 3/4 in x 7 in; 9.525 cm x 12.065 cm x 17.78 cm
ID Number
catalog number
accession number
Credit Line
from Tufts University, Departments of Electrical Engineering and Physics
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Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History


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