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. The date refers to US Patent #538816, issued to Jesse H. Bunnell for an improved "Telegraph Sounder". In this patent, Bunnell claimed to increase the volume of the sound produced by constructing the sounder in such a way as to prevent the weight of the electromagnets from damping out the vibration of the armature. In essence, this acted as a built-in resonator.
Location
Currently not on view
Object Name
telegraph receiver
telegraph sounder
date made
ca 1900
maker
J. H. Bunnell & Co.
Physical Description
wood (overall material)
brass (overall material)
rubber (overall material)
Measurements
overall: 3 1/2 in x 3 in x 5 1/2 in; 8.89 cm x 7.62 cm x 13.97 cm
ID Number
EM.332407
accession number
294351
catalog number
332407
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Communications
Telegraph Sounders
Data Source
National Museum of American History
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Comments

I can verify that Brunell's patent claim is correct. I have both a Brunell sounder and a Western Electric sounder from the time period in my collection, and the Brunell sounder does have a more distinct "click".

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