Bunnell 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 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. An insulated connecting block is attached to the front of the unit with brass brackets that also hold the unit to a table. Each lug on the relay is connected to a corresponding lug on the block with a flat brass plate. Wooden cover. Nameplate on the back: "Type-P-No 143 / 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.330289
label: catalog number
content: 330289
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 3/4 in x 7 5/8 in; 13.97 cm x 22.225 cm x 19.3675 cm