This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Morse Code From Wikipedia, the free encyclopedia 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length of the Morse characters made it hard to adapt to automated circuits, so for most electronic communication it has been replaced by machine readable formats, such as Baudot code and ASCII .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. Development and history A typical "straight key." This U.S. model, known as the J-38, was manufactured in huge quantities during World War II , and remains in widespread use today. In a straight key, the signal is "on" when the knob is pressed, and "off" when it is released. Length and timing of the dots and dashes are entirely controlled by the operator. Beginning in 1836, Samuel F. B. Morse and Alfred Vail developed an electric telegraph , which sent pulses of electrical current to control an electromagnet that was located at the receiving end of the telegraph wire. The technology available at the time made it impossible to print characters in a readable form, so the inventors had to devise an alternate means of communication. In 1837, William Cooke and Charles Wheatstone began operating electric telegraphs in England that also had electromagnets in the receivers; however, their systems used needle pointers that rotated to indicate the alphabetic characters being sent. In contrast, Morse's and Vail's initial telegraph, which first went into operation in 1844, made indentations on a...
View Full Document
This document was uploaded on 02/08/2012.
- Winter '09