Greeley telegraph relay with key
date: label: date made
content: 1883
name: label: maker
content: E. S. Greeley & Company
notes: label: Description
content: Telegraph relays amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
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.331828
label: accession number
content: 294351
label: catalog number
content: 331828
label: collector/donor number
content: 100-031
objectType: label: Object Name
content: telegraph combination device
label: Object Name
content: telegraph relay and key
label: Object Name
content: telegraph relay
label: Object Name
content: telegraph key
label: Other Terms
content: telegraph combination device; Telegraphy
physicalDescription: label: Physical Description
content: wood (part: material)
label: Physical Description
content: brass (part: material)
label: Physical Description
content: plastic (part: material)
label: Physical Description
content: steel (part: material)
label: Measurements
content: overall: 3 in x 12 3/4 in x 7 1/2 in; 7.62 cm x 32.385 cm x 19.05 cm