Western Electric main-line 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.

“Main line” relays like this Western Electric unit were one of the most common types of relay and, as seen in this piece, were typically made with a resistance of 150 ohms. As the name suggests, main line relays served on major intercity circuits several hundred miles long. Better known for their Bell System telephone equipment, Western Electric manufactured a wide range of electrical devices.

Maker: Western Electric

Location: Currently not on view

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

Exhibition:

Exhibition Location:

Credit Line: from Weston Electrical Instrument Corp.

Data Source: National Museum of American History

Id Number: EM.314487Catalog Number: 314487Accession Number: 203371

Object Name: relaytelegraph relay

Physical Description: wood (overall material)metal (overall material)brass (overall material)plastic (overall material)Measurements: overall: 4 in x 9 in x 5 in; 10.16 cm x 22.86 cm x 12.7 cm

Guid: http://n2t.net/ark:/65665/ng49ca746a9-a2be-704b-e053-15f76fa0b4fa

Record Id: nmah_706365

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.