Drawing of Evolved Telegraph - 1854

Samuel Morse's earlier telegraph mechanism to send messages did not involve a telegraph key like the one illustrated above. The first Morse telegraph used ridged slugs, with each slug representing a letter. Morse's early telegraph receiver was a pendulum-like device that used a ribbon of paper to record dots and dashes, which were then deciphered and read by the operator. Soon the system was simplified, and a key or hand transmitter similar to the one above became popular. Clerks eventually learned to read the messages by the sound of the marking lever and, once a "sounder" was added, the Morse telegraph was converted from a paper-based system to an acoustic one.