Telegraph Key

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
cable key
submarine telegraph key
date made
ca 1880
maker
E. S. Greeley & Company
Physical Description
brass (overall material)
metal (overall material)
plastic (overall material)
Measurements
overall: 6 in x 4 1/2 in x 7 in; 15.24 cm x 11.43 cm x 17.78 cm
ID Number
EM*331462
accession number
294351
collector/donor number
03-42
catalog number
331462
subject
Communications
Telegraph Keys
See more items in
Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
from Western Union Corporation

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