Western Electric pony telegraph relay


Telegraph relays 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, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.

So-called “pony” relays like this unit made by Western Electric serviced private lines and shorter branch circuits. The resistance of a given pony relay varied depending on the length of the circuit. This 20 ohm pony relay would have been used on circuits up to about 15 miles in length.

Maker: Western Electric

Location: Currently not on view

See more items in: Work and Industry: Electricity, Communications, Telegraph Relays & Repeaters


Exhibition Location:

Credit Line: from International Business Machines, Inc., William J. Hammer Collection

Data Source: National Museum of American History

Id Number: EM.320524Catalog Number: 320524Accession Number: 241402

Object Name: repeatertelegraph relay

Physical Description: metal (overall material)wood (overall material)plastic (overall material)brass (overall material)Measurements: overall: 3 in x 6 1/2 in x 3 1/2 in; 7.62 cm x 16.51 cm x 8.89 cm

Guid: http://n2t.net/ark:/65665/ng49ca746aa-5905-704b-e053-15f76fa0b4fa

Record Id: nmah_1190746

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