Farmer & Woodman 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. The pulses faded in strength as they traveled through the wire, limiting the distance a message could travel. Repeaters remedied that problem by detecting a weak signal and using a local power source to re-energize and re-transmit the signal down the line.
This repeater was submitted with to the U.S. Patent Office by inventors Moses G. Farmer and Asa F. Woodman in 1856 for their "Improvement in Telegraphic Repeaters." The basic idea of their patent was to prevent to action of the local telegraph circuit from interfering with the retransmission of a message between two distant stations. They received patent #16,828 on 17 March 1857 for this device.
Currently not on view
Object Name
telegraph relay
telegraph repeater
date made
Farmer, Moses G.
Woodman, Asa F.
Physical Description
wood (overall material)
brass (overall material)
cloth (overall material)
steel (overall material)
overall: 4 in x 11 1/2 in x 11 in; 10.16 cm x 29.21 cm x 27.94 cm
ID Number
catalog number
accession number
patent number
Telegraph Relays & Repeaters
See more items in
Work and Industry: Electricity
Telegraph Relays & Repeaters
Data Source
National Museum of American History, Kenneth E. Behring Center
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