Silenced Instrument Key
date: label: date made
content: 1918
name: label: maker
content: L. S. Brach Manufacturing Co.
notes: label: Description (Brief)
content: 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.
label: Description (Brief)
content: Markings: "Signal Corps, U.S. Army / Silenced Instrument Key / Type J-4 / Order No. 7040 Date: 1918 / Mfg. by / L. S. Brach Supply Co., Newark, NJ, U.S.A." A straight wireless telegraph key with knob grip and spring tension adjustment. A pilot lamp assembly permits visual monitoring of current which is connected to three binding post terminals at end of wooden base. The rear contact has a rubber boot to eliminate noise and the front contact features a needle on the bottom of the lever that dips into a mercury cup to make contact.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Telegraph Keys
label: See more items in
content: Communications
creditLine: label: Credit Line
content: from Franklin Wingard
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.321456
label: accession number
content: 241556
label: catalog number
content: 321456
objectType: label: Object Name
content: telegraph key
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: plastic (overall material)
label: Physical Description
content: rubber (overall material)
label: Measurements
content: 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