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Coastal semaphore using moving arms at Scheveningen, circa 1799. Semaphore (lit. ' apparatus for signalling '; from Ancient Greek σῆμα (sêma) 'mark, sign, token' and Greek -φόρος (-phóros) 'bearer, carrier') [1] is the use of an apparatus to create a visual signal transmitted over distance.
Semaphore signals were patented in the early 1840s by Joseph James Stevens, and soon became the most widely used form of mechanical signal. Designs have altered over the intervening years, and colour light signals have replaced semaphore signals in most countries, but in a few they remain in use.
A US Navy crewman signals the letter 'U' using flag semaphore during an underway replenishment exercise (2005). Flag semaphore (from the Ancient Greek σῆμα (sêma) 'sign' and - φέρω (-phero) '-bearer' [1]) is a semaphore system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands.
The first semaphore signals were installed by the German military occupation forces during World War II and are almost identical to the "H/V" signalling system of the Deutsche Reichsbahn of the same period. Main signals consisted of two-arm semaphores and distant signals of yellow disks.
A semaphore signal on the Atchison, Topeka and Santa Fe Railway in 1943. Semaphore signals were first developed in England in 1841. [2]: 169 Some U.S. railroads began to install them in the early 1860s, and semaphores gradually displaced other types of signals. The Union Switch & Signal company (US&S) introduced an electro-pneumatic design in ...
[1] [2] The signals of the Popham semaphore were found to be much more visible than those of the Murray shutter telegraph. [1] Popham's 2-arm semaphore was modelled after the 3-arm Depillon French semaphore. [1] An experimental semaphore line between the Admiralty and Chatham was installed in July 1816, and its success helped to confirm the ...
Pasley had invented a system of optical telegraphy through semaphores in 1822 for the British military, and appears to have suggested to Gregory the application of the semaphore to railway signaling. [9] The semaphore was afterwards rapidly adopted as a fixed signal nearly universally. Disc signals, such as those made by the Hall Signal Company ...
The International Code of Signals (INTERCO) is an international system of signals and codes for use by vessels to communicate important messages regarding safety of navigation and related matters. Signals can be sent by flaghoist , signal lamp ("blinker"), flag semaphore , radiotelegraphy, and radiotelephony.