Telegraph Resonator

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. A resonator like this was used to amplify the sound, making it easier for an operator to hear his or her own sounder when working in a room filled with these devices. This unit originally held two resonatod hoods though only one is left on the stand.
Currently not on view
date made
ca 1870
Physical Description
wood (overall material)
brass (overall material)
steel (overall material)
resonator only: 6 in x 5 in x 4 in; 15.24 cm x 12.7 cm x 10.16 cm
overall: 16 in x 19 in x 8 in; 40.64 cm x 48.26 cm x 20.32 cm
ID Number
accession number
collector/donor number
catalog number
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Telegraph Sounders
Data Source
National Museum of American History


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