Unspecified / ca 1890
Telegraph Key
Telegraph Key
The Smithsonian catalogs Telegraph Key as cable key in its Telegraph records.
WHY IT’S INTERESTING
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 m