The coaxial cable is a suitable transfer medium not only for TV signals but also for data transmissions. History – early years of Data Networks In the first stage of computer network development, the coaxial cable was used as a shared medium for all connected computers. Data sent from one computer was distributed by common cable to all other computers. Each of them therefore “listened” to all communication and had
Optical transmission systems are based on the transmission of light guide fiber information. Laser diodes are used as a light source, and photodetectors are used at the other end of the fiber. Optic Fiber Depending on the material used, we distinguish optical fibers made from glass and plastic, with glass being of better quality. Depending on the thickness of the light-guide core, the fibers are divided into multi-mode and single-mode.
Operation principle The multiswitch is a device, that is inserted between LNB and satellite receiver. From receiver’s point of view the multiswitch acts as an universal switchable LNB supplying signals in satellite polarization which must be requested using adequate control commands. Any receiver included in the distribution system has access to any channel broadcasted by a given satellite, which is the main advantage of using a multiswitch distribution. In case
The DiSEqC system designed by EUTELSAT provides a method of controlling a wide range of equipment and accessories connected to the satellite receiver. The abbreviation DiSEqC means Digital Satellite Equipment Control. A 22 kHz amplitude modulation is used to form DiSEqC data bits and messages and their transmission via a cable. In principle, logical1 data bit is represented by a 0.5 ms burst of a 22 kHz tone (of approx. 0.6 V amplitude) followed by a 1 ms
The idea to use a man-made satellite for communications first appeared at the end of World War II. British mathematician and sci-fi author Arthur C. Clarke proposed to put a communication satellite on a geostationary orbit at a height of 36000 km above the equator from where it can reach up to 40% of the earth’s surface, with television and radio signals which can be intercepted by countless receiving stations