Morse Code was developed by three people in the mid-1830s - American artist Samuel Morse (for whom the code is named), American physicist Joseph Henry, and American inventor Alfred Vail. The code was originally invented so that messages could be sent along telegraph lines in the form of an electric current. Each letter of the alphabet and number from 0 to 9 was translated into a series of electrical pulses (for example, A is a short pulse followed by a long pulse, B is a long pulse followed by three short pulses, and so on), with each letter being followed by a silence to indicate that the code was complete.
Operators at either end could input the code and could listen to the clicks made by these pulses when transmitted over an electrical cable to send messages quickly over long distances. Originally, Morse, Henry and Vail developed the code so that it could be 'punched' into a length of paper at the receiving end, which meant that an operator was not required to e continually present at the receiving end. Any received messages were punched into paper strips and could be picked up and translated at a later time. The receiving piece of equipment (known as an armature) made a clicking sound when punching through the paper, which operators realised could easily be translated into dots and dashes and written out by hand, removing the need for paper to punch the message on to. Highly trained operators at either end could rapidly transcribe messages and send and receive them over long distances, opening up new forms of telecommunications at speed.
In the late 1800s (around 1890), Morse code had been refined into a standardized alphabet, and began being used over radio rather than relying on physical electrical cables. Although most messages were still send over physical cables, this meant that communication with aircraft was now possible, and began being regularly used in the 1920s once the receiving equipment was reduced to a useful size. Although radiographic communication was therefore available during the First World War, it was little used. However, radio communications over Morse code were vital during World War 2, especially for carrying radio communications between bases and craft on missions.
Although international Morse code is still used in the present day, its use has been superceded by the development of voice communications technologies. Only a small number of people are now trained in its use every year, with amateur enthusiasts the main users now.