Telegraph Key

Telegraph Key

Usage conditions apply
Downloads
Description (Brief)
Telegraph keys are electrical switches used to send coded messages that travel as a series of electrical pulses through a wire. Due to special difficulties in sending pulses through long underwater cables, so-called double-current keys were used. Instead of the short dots and long dashes of land-line telegraphs, submarine telegraphs sent positive pulses and negative pulses that made the receiver move right or left. The operator pressed one lever on the key to send a positive pulse and another to send a negative pulse. The code consisted of the sequence of left and right movements recorded on a paper tape.
Location
Currently not on view
Object Name
telegraph key
cable key
submarine telegraph key
date made
ca 1880
Physical Description
brass (overall material)
metal (overall material)
plastic (overall material)
Measurements
overall: 5 3/4 in x 4 1/4 in x 6 in; 14.605 cm x 10.795 cm x 15.24 cm
ID Number
EM.331461
accession number
294351
catalog number
331461
collector/donor number
03-38
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Communications
Telegraph Keys
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.

Comments

Add a comment about this object