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A Guide to Vintage Telegraph Sounders

The age of the telegraph ended with the advent of the telephone. Now that we've moved onto smartphones, which give us instant access to centuries worth of information, communicating via dots and dashes seems quaint. The telegraph was an essential innovation in the history of human connectivity, however, and vintage tech enthusiasts can find plenty of telegraph sounders for sale on eBay.

What is a telegraph sounder?

As the telegraph gained wider use in the 19th century, scientists scrambled to develop new modes of receiving messages. By the middle of the 1800s, the Morse code had become the most popular way of encoding messages. This signaling alphabet, which uses a series of dots and dashes to represent characters, was transmitted across long distances using electric telegraph lines. In 1850, 13 years after Samuel Morse patented the electrical telegraph, his assistant Alfred Vail invented the telegraph sounder. This device was used to receive telegraph communications, and it marked the first time that electromagnet technology was used in telegraph transmissions.

How does the telegraph sounder work?

The telegraph sounder uses a relatively simple mechanism to relay telegraphed messages. Inside the sounder is an electromagnet, which is connected to the telegraph line. There is an iron armature located near the electromagnet's pole, which is held aloft by a counterweight and balanced on a pivot. When the sounder receives a message from the connected telegraph line, the current flows through the electromagnetic winding, which results in a magnetic field. This exerts force on the armature, which makes a clicking noise each time it comes into contact with the electromagnet. When the current dissipates and the armature returns to its normal position, it makes a clacking sound. These sounds, which occur when the circuit is broken and when the circuit begins again, are interpreted as the dashes and dots of Morse code.

What are the main components of antique telegraph sounders?

When you're on the hunt for a vintage telegraph sounder, look for the following components:

  • Wooden base: The main components of the sounder are typically mounted on a wooden base that stands about four inches high.
  • Assembly: The main assembly is a hammer and anvil mechanism, which is connected to the magnetic circuit.
  • Magnetic circuit: To complete the magnetic circuit, sounders were equipped with copper wire wound around a core of iron, which was surrounded on either side by top and bottom pieces.
  • Keys: As they're intended to receive messages, not all telegraph sounders come with keys, the devices used to tap out the Morse code messages. You can find antique telegraph key and sounder devices, however, also known as pocket relays.
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