Semi-automatic Telegraph Key

Description (Brief)
Telegraph keys are electrical on-off switches used to send messages in Morse code. A semi-automatic telegraph key like this one allows an operator to send land-line and wireless (radio) telegraph messages at a much faster rate than with an ordinary key. The key automatically produces rapid morse code dots by using a weighted pendulum to quickly make and break contact in the electrical circuit. The operator still makes the dashes manually. This later Mecograph semi-automatic telegraph key shows a traditional straight-arm design rather than the company's signature right-angle design.
Currently not on view
Mecograph Company
Physical Description
metal (overall material)
plastic (overall material)
cloth (overall material)
overall: 2 1/2 in x 3 in x 8 1/4 in; 6.35 cm x 7.62 cm x 20.955 cm
ID Number
accession number
catalog number
Credit Line
from Western Union Corporation
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Work and Industry: Electricity
Telegraph Keys
Data Source
National Museum of American History


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