All American Cables type PF polar telegraph relay
notes: label: Description
content: Telegraph relays amplify an electrical signal in a telegraph line. Telegraph messages travel as a series of electrical pulses through a wire from a transmitter to a receiver. The pulses fade in strength as they travel through the wire, limiting the distance a message can be sent. Relays remedy that problem by detecting a weak signal and automatically re-transmitting that signal down the line using a local power source.
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.330275
label: catalog number
content: 330275
label: accession number
content: 288763
objectType: label: Object Name
content: polar relay
label: Object Name
content: telegraph polar relay
label: Object Name
content: telegraph relay
label: Other Terms
content: telegraph relay; Telegraphy
physicalDescription: label: Measurements
content: overall: 3 3/4 in x 5 1/2 in; 9.525 cm x 13.97 cm