Silenced Instrument Key

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Description (Brief)
Telegraph keys are electrical on-off switches used to send messages in Morse code. This Silenced Instrument Key was made for US Army by L. S. Brach Company in 1918 and is designed to make no noise when the operator is sending. The front contact features a needle on the bottom of the lever that dips into a mercury cup to quietly complete the circuit. The rear contact has a rubber boot to silence the return action. A small light bulb assembly permits the operator to visually monitor the signal.
Currently not on view
date made
L. S. Brach Manufacturing Co.
Physical Description
wood (overall material)
metal (overall material)
plastic (overall material)
rubber (overall material)
overall: 3 3/4 in x 3 1/2 in x 13 1/2 in; 9.525 cm x 8.89 cm x 34.29 cm
ID Number
accession number
catalog number
Credit Line
from Franklin Wingard
See more items in
Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History, Kenneth E. Behring Center


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