Telegraph Key
date: label: date made
content: ca 1895
name: label: maker
content: Silvertown Telegraph Works
label: maker
content: India-rubber, Gutta-percha, and Telegraph Works Company
notes: label: Description (Brief)
content: Telegraph keys are electrical switches used to send messages in code. The message travels as a series of electrical pulses through a wire. This British key was designed for use on underwater telegraph cables. Typical telegraph keys turn the current on and off in the line. This double-current key keeps the battery on the line and reverses the direction of the current flow when the operator presses down on the lever. Setting the small lever to “receive” sends the current to a separate relay instead of through the main section of the key. Silvertown Telegraph Works, London.
label: Description (Brief)
content: This is a European double-current telegraph keyer, mounted on a walnut base. One sending knob operates two sets of contacts enclosed in a brass case with a glass top. A small lever beside the control knob has two positions: send and receive. Brass fittings, wooden knobs. "Silvertown, London" printed on the top. Reference: Prescott 1892, volume 1, pages 499-501. "The double current key which is used for long circuits in England, India and other countries is so arranged as to completely reverse the battery after each signal. That is to say instead of the spaces between the signals being formed by merely breaking the circuit, a reverse current is sent into the line so that the battery when working is always connected to the line in one direction or the other. Fig. 270 shows the arrangement of the double current key usually employed in England."
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Telegraph Keys
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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.330242
label: catalog number
content: 330242
label: accession number
content: 288763
objectType: label: Object Name
content: telegraph key
label: Object Name
content: cable key
label: Object Name
content: submarine telegraph key
physicalDescription: label: Physical Description
content: brass (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: wood (overall material)
label: Measurements
content: overall: 4 1/4 in x 4 3/4 in x 8 1/4 in; 10.795 cm x 12.065 cm x 20.955 cm