Bunnell type-P submarine telegraph relay
date: label: date made
content: ca 1900
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: Transmitting relay for a submarine telegraph system. A wooden casing on which is mounted nine terminal lugs and two electromagnet relays, each relay having a pair of coils. Wiring and two more coils are inside the casing which is attached to the wooden base with two knurled knobs. Wooden cover. Nameplate on the back: "Type-P-No 130 / J.H. Bunnell & Co. / New York, U.S.A."
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 ITT World Communications, Inc., thru John Van Ingen
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.330290
label: catalog number
content: 330290
label: accession number
content: 288763
objectType: label: Object Name
content: submarine telegraph relay
label: Object Name
content: telegraph relay
label: Other Terms
content: telegraph relay; Telegraphy; Transmitter
physicalDescription: label: Measurements
content: overall: 5 1/2 in x 8 in x 6 1/8 in; 13.97 cm x 20.32 cm x 15.5575 cm