Telegraph Sounder
name: label: maker
content: J. H. Bunnell & Co.
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: So-called “pony” relays like this unit made by J. H. Bunnell & Co., serviced private lines and shorter branch circuits. The resistance of a given pony relay varied depending on the length of the circuit. This 50 ohm pony relay would have been used on circuits up to about 45 miles in length.
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
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content: Telegraph Relays & Repeaters
creditLine: label: Credit Line
content: from Weston Electrical Instrument Corp.
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.314488
label: catalog number
content: 314488
label: accession number
content: 203371
objectType: label: Object Name
content: relay
label: Object Name
content: telegraph relay
physicalDescription: label: Physical Description
content: wood (overall material)
label: Physical Description
content: metal (overall material)
label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: 3 1/2 in x 3 in x 6 in; 8.89 cm x 7.62 cm x 15.24 cm