Bunnell duplex telegraph relay
date: label: date made
content: ca 1920
name: label: maker
content: J. H. Bunnell & Co.
label: maker
content: J. H. Bunnell
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: Description
content: This relay is a model from the early 20th century and was designed for duplex lines that could carry two messages simultaneously on the same wire. The unit bears an inspection stamp "N.Y.R.S. 9 24" indicating that it was serviced at Western Union's New York Repair Shop in September 1924.
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
label: See more items in
content: Telegraph Relays & Repeaters
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.331390
label: catalog number
content: 331390
label: accession number
content: 294351
label: collector/donor number
content: 100-027
objectType: label: Object Name
content: telegraph relay
label: Object Name
content: duplex telegraph relay
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: steel (overall material)
label: Physical Description
content: iron (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 4 in x 8 1/4 in x 4 3/4 in; 10.16 cm x 20.955 cm x 12.065 cm