Morse code is a type of character encoding that transmits telegraphic information using rhythm. Morse code uses a standardized sequence of short and long elements to represent the letters, numerals, punctuation and special characters of a given message. The short and long elements can be formed by sounds, marks, or pulses, in on off keying and are commonly known as "dots" and "dashes" or "dits" and "dahs". The speed of Morse code is measured in words per minute (WPM) or characters per minute, while fixed-length data forms of telecommunication transmission are usually measured in baud or bps.
Originally created for Samuel F. B. Morse's electric telegraph in the early 1840s, Morse code was also extensively used for early radio communication beginning in the 1890s. For the first half of the twentieth century, the majority of high-speed international communication was conducted in Morse code, using telegraph lines, undersea cables, and radio circuits. However, the variable length of the Morse characters made it hard to adapt to automated circuits, so for most electronic communication it has been replaced by machine readable formats, such as Baudot code and ASCII.
The most popular current use of Morse code is by amateur radio operators, although it is no longer a requirement for amateur licensing in many countries. In the professional field, pilots and air traffic controllers are usually familiar with Morse code and require a basic understanding. Navigational aids in the field of aviation, such as VORs and NDBs, constantly transmit their identity in Morse code. Morse code is designed to be read by humans without a decoding device, making it useful for sending automated digital data in voice channels. For emergency signaling, Morse code can be sent by way of improvised sources that can be easily "keyed" on and off, making Morse code one of the most versatile methods of telecommunication in existence.
I checked out the Development and History section of the Morse Code article and I must say that I learned something new! Having not known much about the history of Morse Code, I had always assumed that it was originally invented for the same reasons that it has been used for the last 150+ years. Surprisingly enough, the technology evolved through some interesting methods... history never ceases to amaze!
On another note, if the world and all of it's technology were to be turned upside down one day, one could depend on basic technologies such as Morse Code for communication. Those possessing this knowledge would be indispensable! Unfortunately, like many old-school technologies and skills, they are falling by the wayside as digital technologies take over. But one day, it will all blink off and we'll need to know how to do things old-school again... one can only hope the library has some good info in print. But, I digress...