Telegraph Key
date: label: date made
content: ca 1880
name: label: maker
content: E. S. Greeley & Company
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: 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 Western Union Corporation
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.331462
label: accession number
content: 294351
label: collector/donor number
content: 03-42
label: catalog number
content: 331462
objectType: label: Object Name
content: telegraph key
label: Object Name
content: cable key
label: Object Name
content: submarine telegraph key
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 6 in x 4 1/2 in x 7 in; 15.24 cm x 11.43 cm x 17.78 cm