Telegraph Sounder

Description (Brief)
Telegraph sounders convert electrical pulses into audible sounds and are used to receive Morse code messages. The message travels as a series of electrical pulses through a wire. Short pulses make a dot, slightly longer pulses make a dash. The sequence of dots and dashes represent letters and numbers. The pulses energize the sounder’s electromagnets which move a lever-arm. The arm makes a loud “click” when it strikes a crossbar and the operator translates the pattern of sounds into the original language. The date for US Patent #165156 is stamped on this sounder. That patent was issued to Patrick B. Delany of Jersey City, NJ., on 6 July 1875 for an "Improvement in Automatic Telegraphs." Delany's patent was intended to address the issue of induced currents in a telegraph line that created "false records or signals" by activating the sounder during the pauses between dots and dashes. This became a problem with the adoption of automatic sending devices that could transmit messages faster than human operators.
Location
Currently not on view
Object Name
telegraph receiver
telegraph sounder
date made
ca 1875
Physical Description
wood (overall material)
brass (overall material)
rubber (overall material)
nickle (overall material)
Measurements
overall: 3 3/4 in x 3 in x 5 5/8 in; 9.525 cm x 7.62 cm x 14.2875 cm
ID Number
EM*332364
accession number
294351
catalog number
332364
See more items in
Work and Industry: Electricity
Communications
Telegraph Sounders
Data Source
National Museum of American History, Kenneth E. Behring Center

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