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  2. Slow-scan television - Wikipedia

    en.wikipedia.org/wiki/Slow-scan_television

    Slow-scan television ( SSTV) is a picture transmission method, used mainly by amateur radio operators, to transmit and receive static pictures via radio in monochrome or color. A literal term for SSTV is narrowband television. Analog broadcast television requires at least 6 MHz wide channels, because it transmits 25 or 30 picture frames per ...

  3. Morse code - Wikipedia

    en.wikipedia.org/wiki/Morse_code

    Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs. [3] [4] Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy . International Morse code encodes the 26 ...

  4. Heterodyne - Wikipedia

    en.wikipedia.org/wiki/Heterodyne

    When these damped waves were received by a simple detector, the operator would hear an audible buzzing sound that could be transcribed back into alpha-numeric characters. With the development of the arc converter radio transmitter in 1904, continuous wave (CW) modulation began to be used for radiotelegraphy. CW Morse code signals are not ...

  5. Baudot code - Wikipedia

    en.wikipedia.org/wiki/Baudot_code

    The Baudot code ( French pronunciation: [boˈdo]) is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. [1] It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use before ASCII. Each character in the alphabet is represented by a series of five bits ...

  6. Telegraph sounder - Wikipedia

    en.wikipedia.org/wiki/Telegraph_sounder

    Telegraph Sounder. A telegraph sounder is an antique electromechanical device used as a receiver on electrical telegraph lines during the 19th century. It was invented by Alfred Vail after 1850 to replace the previous receiving device, the cumbersome Morse register [1] and was the first practical application of the electromagnet.

  7. American Morse code - Wikipedia

    en.wikipedia.org/wiki/American_Morse_code

    American Morse code. American Morse Code — also known as Railroad Morse—is the latter-day name for the original version of the Morse Code developed in the mid-1840s, by Samuel Morse and Alfred Vail for their electric telegraph. The "American" qualifier was added because, after most of the rest of the world adopted " International Morse Code ...

  8. History of telegraphy in Australia - Wikipedia

    en.wikipedia.org/wiki/History_of_telegraphy_in...

    The last morse code message on the eastern seaboard was sent in early 1963. In 1993, Australia Post discontinued its letter-gram service, which consisted of postage delivery "telegrams"; that is, messages typed as a genuine telegram, and delivered in the same manner (although never transmitted over telegraph lines).

  9. Morse code mnemonics - Wikipedia

    en.wikipedia.org/wiki/Morse_code_mnemonics

    Morse code mnemonics are systems to represent the sound of Morse characters in a way intended to be easy to remember. Since every one of these mnemonics requires a two-step mental translation between sound and character, none of these systems are useful for using manual Morse at practical speeds. Amateur radio clubs can provide resources to ...