Telegraph sounders convert electrical pulses into audible sounds and are used to receive Morse code messages. The message travels as a series of electrical pulses through a wire. Short pulses make a dot, slightly longer pulses make a dash. The sequence of dots and dashes represent letters and numbers. The pulses energize the sounder’s electromagnets which move a lever-arm. The arm makes a loud “click” when it strikes a crossbar and the operator translates the pattern of sounds into the original language. This sounder, made by Western Electric, is rated at 50 ohms. Lower resistance units such as this tended to be used on local lines only a few miles in length.
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.