Q. Explain about Transmission Media?
These, also known as physical channels, can be either bounded or unbounded. Bounded media, in which signals representing data are confined to the physical media, are twisted pairs of wires, coaxial cables, and optical-fiber cables, used in most LANs. Unbounded media, such as the atmosphere, the ocean, and outer space inwhich the transmission iswireless, use infrared radiation, lasers, microwave radiation, radio waves, and satellites. Data are transmitted from one node to another through various transmission media in computer communications networks.
Twisted pairs are used in low-performance and low-cost applications with a data rate of about 1 Mbit per second (Mbps) for a transmission distance of about 1 km. Baseband coaxial cables used for digital transmission are usually 50- cables with a data rate of about 10 Mbps over a distance of about 2 km. Broad-band coaxial cables used for analog transmission (cable TV) are usually 75- cables with a data rate of about 500 Mbps over a distance of about 10 km. The lighter and cheaper fiber-optic cables support data transmission of about 1 Gbps over a distance of about 100 km.