Telegraph Call Box and 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.
This sounder is mounted on a board along with a call box from the Postal Telegraph Company. Call boxes placed in business offices allowed quick service for those who often sent telegrams. Activating the call box would alert Postal that one of their customers needed to send a telegram. Each box sent a specific number so the company could quickly dispatch a messenger to the correct address. The messenger retrieved the message and brought it back to the Postal office for transmission.
Currently not on view
J. H. Bunnell & Co.
Viaduct Company
Physical Description
wood (overall material)
brass (overall material)
rubber (overall material)
ceramic (overall material)
overall: 4 in x 15 1/4 in x 12 in; 10.16 cm x 38.735 cm x 30.48 cm
sounder: 3 1/4 in x 5 1/2 in x 3 1/4 in; 8.255 cm x 13.97 cm x 8.255 cm
ID Number
collector/donor number
accession number
catalog number
Credit Line
from Western Union Corporation
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Work and Industry: Electricity
Telegraph Sounders
Data Source
National Museum of American History


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