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Semaphore
Semaphore (; ) is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms. Semaphores can be used for telegraphy when arranged in Optical telegraph, visually connected networks, or for traffic signalling such as in Railway semaphore signal, railway systems, or traffic lights in cities. Fire The Phryctoriae were a semaphore system used in Ancient Greece for the transmission of specific prearranged messages. Towers were built on selected mountaintops, so that one tower, the ''phryctoria'', would be visible to the next tower, usually distant. Flames were lit on one tower, then the next tower would light a flame in succession. The Byzantine beacon system was a semaphore developed in the 9th century during the Arab–Byzantine wars. The Byzantine Empire used a system of beacons to transmit messages from the border with the Abbasid Caliphate across Asia Minor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telegraph
An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals (a form of optical communication). There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and conveys information according to the direction the indicators point, and the shutter telegraph which uses panels that can be rotated to block or pass the light from the sky behind to convey information. The most widely used system was the Chappe telegraph, which was invented in France in 1792 by Claude Chappe. It was popular in the late eighteenth to early nineteenth centuries. Chappe used the term ''télégraphe'' to describe the mechanism he had invented – that is the origin of the English word "telegraph". Lines of relay towers with a semaphore rig at the top were built within line of sight of each other, at separations of . Operators at each tower would watch the neighboring tower through a telescop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railway Semaphore Signal
Railway semaphore signals are an early form of fixed railway signals. The semaphore system involves signals that display their different indications to Railroad engineer, train drivers by changing the angle of inclination of a pivoted 'arm'. 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. Origins The first railway semaphore signal was erected by Charles Hutton Gregory in about 1842, on the London and Croydon Railway (later the London Brighton and South Coast Railway) at New Cross, southeast London, as part of the newly enlarged layout also accommodating the South Eastern Railway. John Urpeth Rastrick claimed to have suggested the idea to Hutton Gregory. The semaphore was swiftly embraced across Britain and North America as a fixe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
