Lindsey telegraph repeater patent model. Telegraph repeaters amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. NMAH2002-11467

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Photo credit: © SBS Eclectic Images / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: electricity, industry, work