Know about Semaphore telegraph tower as Amitabha Gupta, a renowned blogger, gives a detailed description of it. A semaphore telegraph is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. The most widely used system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth centuries.
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<bdo lang="en" dir="ltr"><a href="//commons.wikimedia.org/wiki/Commons:YouTube_files" title="Commons:YouTube files">YouTube</a>: <a rel="nofollow" class="external text" href="https://www.youtube.com/watch?v=Ok5bc8p4Bng"><bdi lang="">SEMAPHORE TELEGRAPH TOWER AT CHATNA IN BANKURA.</bdi></a> – View/save archived versions on <a rel="nofollow" class="external text" href="https://web.archive.org/web/*/https://www.youtube.com/watch?v=Ok5bc8p4Bng">archive.org</a> and <a rel="nofollow" class="external text" href="https://archive.today/https://www.youtube.com/watch?v=Ok5bc8p4Bng">archive.today</a></bdo>