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Semi-automatic Telegraph Key

Semi-automatic Telegraph Key

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Usage conditions apply
Description (Brief)
Semi-automatic keys like this one 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.
Electric Specialty Manufacturing Company produced this key under license from a company that worked with Horace Martin, inventor of "Vibroplex" semi-automatic key.
Currently not on view
Object Name
sending key
telegraph key
Electric Specialty Manufacturing Company
Physical Description
steel (overall material)
plastic (overall material)
cloth (overall material)
rubber (overall material)
copper (overall material)
overall: 10 cm x 23 cm x 7.5 cm; 3 15/16 in x 9 1/16 in x 2 15/16 in
ID Number
accession number
catalog number
Credit Line
from Mr. and Mrs. Dan Hobaugh
See more items in
Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History
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