Optical Switches (Packet and Circuit
... • a cantilever made of soft magnetic material with a reflective surface serving as a mirror. ...
... • a cantilever made of soft magnetic material with a reflective surface serving as a mirror. ...
Lecture_2012_1
... One OC-192 optical signal = 10x109 bps One optical fiber carries 160 OC-192 signals = 1.6x1012 bps! ...
... One OC-192 optical signal = 10x109 bps One optical fiber carries 160 OC-192 signals = 1.6x1012 bps! ...
early forms of long-distance communication
... the semaphore consisted of a series of hilltop stations that each had large movable arms to signal letters and numbers and two telescopes with which to see the other stations. Like ancient smoke signals, the semaphore was susceptible to weather and other factors that hindered visibility. A different ...
... the semaphore consisted of a series of hilltop stations that each had large movable arms to signal letters and numbers and two telescopes with which to see the other stations. Like ancient smoke signals, the semaphore was susceptible to weather and other factors that hindered visibility. A different ...
Computer networks and the Internet
... Computer networks and the Internet • ARPANET would eventually merge with other networks to form the Internet and many of the protocols the Internet relies upon today were specified . In September 1981, RFC 791 introduced the Internet Protocol v4 (IPv4) and RFC 793 introduced the Transmission Contro ...
... Computer networks and the Internet • ARPANET would eventually merge with other networks to form the Internet and many of the protocols the Internet relies upon today were specified . In September 1981, RFC 791 introduced the Internet Protocol v4 (IPv4) and RFC 793 introduced the Transmission Contro ...
Semaphore line
A semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, or Napoleonic semaphore 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 system was invented in 1792 in France by Claude Chappe, and was popular in the late eighteenth to early nineteenth century.They were much faster than post riders for bringing a message over long distances, and also cheaper in their long-term operating costs, once constructed. Semaphore lines were a precursor of the electrical telegraph which would replace them half a century later. The electrical telegraph would in turn be cheaper, faster, and more private. The distance that an optical telegraph can bridge is limited by geography and weather; thus, in practical use, most optical telegraphs used lines of relay stations to bridge longer distances. This also prevented the optical telegraph from crossing long expanses of water, unless a convenient island could be used for a relay station.Modern derivatives of the semaphore system include flag semaphore (a flag relay system) and the heliograph (optical telegraphy using mirror-directed sunlight reflections).