Vibroplex Telegraph Key

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Description (Brief)
Telegraph keys are electrical on-off switches used to send messages in Morse code. Horace G. Martin patented a practical semi-automatic telegraph key in 1903 and his company dominated the market for these devices. Keys like Martin's "Vibroplex" automatically produced rapid morse code dots by using a weighted pendulum to quickly make and break contact in the electrical circuit. The operator would make the dashes manually but could send much faster than with an ordinary key.
Currently not on view
Martin, Horace G.
Physical Description
iron (overall material)
copper (overall material)
slate (overall material)
plastic (overall material)
overall: 2 1/2 in x 3 1/2 in x 8 in; 6.35 cm x 8.89 cm x 20.32 cm
ID Number
catalog number
accession number
Credit Line
from J. Vanderhoof
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Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History