摩尔斯电码
电报通信的语言是由电码符号组成的。电报通信最早是由美国的摩尔斯在 １８４４年发明的，所以电码符号也被叫做摩尔斯电码（Morse code）。电码 符号由两种基本信号和不同的间隔时间组成：短促的点信号“ ．”，读“ 的 ”（Di）；保持一定时间的长信号“─”，读“答 ─”（Da）。 由于各国文字不同，电码符号也不尽相同，比如中国、日本及俄国都有代 表本国文字的电码符号。在业余无线电通信中，全世界运用统一的电码。

Morse code
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From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Morse_code

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length of the Morse characters made it hard to adapt to automated circuits, so for most electronic communication it has been replaced by machine readable formats, such as Baudot code and ASCII.The most popular current use of Morse code is by amateur radio operators, although it is no longer a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.

Modern International Morse Code
Morse code has been in use for more than 160 years — longer than any other electronic encoding system. What is called Morse code today is actually somewhat different from what was originally developed by Vail and Morse. The Modern International Morse code, or continental code, was created by Friedrich Clemens Gerke in 1848 and initially used for telegraphy between Hamburg and Cuxhaven in Germany. After some minor changes, in 1865 it was standardised at the International Telegraphy congress in Paris (1865), and later made the norm by the International Telecommunication Union (ITU) as International Morse code. Morse's original code specification, largely limited to use in the United States, became known as American Morse code or "railroad code." American Morse is now very rarely used except in historical re-enactments.