Bunnell duplex telegraph relay

Description:

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.

This relay is a model from the early 20th century and was designed for duplex lines that could carry two messages simultaneously on the same wire. The unit bears an inspection stamp "N.Y.R.S. 9 24" indicating that it was serviced at Western Union's New York Repair Shop in September 1924.

Date Made: ca 1920

Maker: J. H. Bunnell & Co.J. H. Bunnell

Location: Currently not on view

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

Exhibition:

Exhibition Location:

Credit Line: from Western Union Corporation

Data Source: National Museum of American History

Id Number: EM.331390Catalog Number: 331390Accession Number: 294351Collector/Donor Number: 100-027

Object Name: telegraph relayduplex telegraph relay

Physical Description: wood (overall material)brass (overall material)steel (overall material)iron (overall material)plastic (overall material)Measurements: overall: 4 in x 8 1/4 in x 4 3/4 in; 10.16 cm x 20.955 cm x 12.065 cm

Guid: http://n2t.net/ark:/65665/ng49ca746ac-c500-704b-e053-15f76fa0b4fa

Record Id: nmah_1365334

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