Telegraph Key
name: label: maker
content: O. & F. H. Varley
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.332225
label: collector/donor number
content: 100-692
label: accession number
content: 294351
label: catalog number
content: 332225
objectType: label: Object Name
content: telegraph 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: 2 3/4 in x 3 5/8 in x 6 1/8 in; 6.985 cm x 9.2075 cm x 15.5575 cm