Western Union box 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.
Box relays like this unit used by Western Union were special relays most often used by linemen or station operators for testing purposes or where a local battery was not available. The covering box acted as a resonator that amplified the sound of the relay’s light-weight armature, making the signal audible without a sounder. The relay includes a built-in telegraph key.
Location
Currently not on view
Physical Description
wood (overall material)
brass (overall material)
metal (overall material)
cloth (overall material)
plastic (overall material)
Measurements
overall: 3 in x 9 1/4 in x 5 1/4 in; 7.62 cm x 23.495 cm x 13.335 cm
ID Number
EM*294351.012
accession number
294351
catalog number
294351.012
Credit Line
from Western Union Corporation
See more items in
Work and Industry: Electricity
Communications
Telegraph Relays & Repeaters
Data Source
National Museum of American History, Kenneth E. Behring Center

Comments

Add a comment about this object