Telegraph Sounder

Telegraph Sounder

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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. This sounder was reportedly used by Joseph Henry, first Secretary of the Smithsonian, in his experimental work. Henry made significant accomplishments in developing electromagnets that directly affected telegraph equipment design.
Currently not on view
Object Name
telegraph receiver
telegraph sounder
Other Terms
telegraph sounder; Telegraphy
date made
ca 1860
Henry, Joseph
Chester, Charles T.
Chester, J. N.
Physical Description
wood (overall material)
brass (overall material)
steel (overall material)
copper (overall material)
cloth (overall material)
lead (overall material)
paper (overall material)
overall: 4 in x 4 5/8 in x 8 1/2 in; 10.16 cm x 11.7475 cm x 21.59 cm
ID Number
catalog number
accession number
Credit Line
from the Smithsonian Institution Collection of Apparatus, thru William C. Winlock
See more items in
Work and Industry: Electricity
Telegraph Sounders
Data Source
National Museum of American History
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This is called a "walking beam" type sounder. It is the earliest form of telegraph sounder. There were also relays constructed in this construction style as well. These are usually denoted by their additional brass binding post terminals and insulated sections (usually hard rubber, gutta percha, or ivory).

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