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.

Date Made: ca 1875

Location: Currently not on view

See more items in: Work and Industry: Electricity, Communications, Telegraph Sounders


Exhibition Location:

Credit Line: from Western Union Corporation

Data Source: National Museum of American History

Id Number: EM.332364Accession Number: 294351Catalog Number: 332364

Object Name: telegraph receivertelegraph sounder

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


Record Id: nmah_891420

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