Telegraph Key
date: label: date made
content: ca 1890
name: label: maker
content: Foote, Pierson & Co.
notes: label: Description (Brief)
content: 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.
label: Description (Brief)
content: A double key for submarine telegraphy. A hard rubber base with four feet on which is mounted two telegraph keys side-by-side and four binding posts. Circuit is inlaid on bottom, wires are covered by wax. No extant maker's marks.
label: Location
content: Currently not on view
topic: label: Subject
content: Telegraph
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Telegraph Keys
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content: Communications
creditLine: label: Credit Line
content: from Western Union International
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.329942
label: accession number
content: 283729
label: catalog number
content: 329942
objectType: label: Object Name
content: cable key
label: Object Name
content: telegraph key
label: Object Name
content: submarine telegraph key
physicalDescription: label: Physical Description
content: slate (overall material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 2 1/2 in x 4 1/2 in x 6 1/4 in; 6.35 cm x 11.43 cm x 15.875 cm