Explain different types of physical media (guided and unguided) in detail
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Answer:
Types of physical media
Copper wire
Copper wire is currently the most commonly used type of physical media due to the abundance of copper in the world, as well as its ability to conduct electrical power.
Optical fiber
Optical fiber is a thin and flexible piece of fiber made of glass or plastic. Unlike copper wire, optical fiber is typically used for long-distance data communications, being that it allows for data transmission over far distances and can produce high transmission speeds. Optical fiber also does not require signal repeaters, which ends up reducing maintenance costs, since signal repeaters are known to fail often.
Coaxial cables
Coaxial cables have two different layers surrounding a copper core. The inner most layer has an insulator. The next layer has a conducting shield. These are both covered by a plastic jacket. Coaxial cables are used for microwaves, televisions and computers. This was the second transmission medium to be introduced (often called coax), around the mid-1920s. In the center of a coaxial cable is a copper wire that acts as a conductor, where the information travels. The copper wire in coax is thicker than that in twisted-pair, and it is also unaffected by surrounding wires that contribute to electromagnetic interference, so it can provide higher transmission rates than the twisted-pair. The center conductor is surrounded by plastic insulation, which helps filter out extraneous interference. This insulation is covered by a return path, which is usually braided-copper shielding or aluminum foil type covering. Outer jackets form a protective covering for coax; the number and type of outer jackets depend on the intended use of the cable (e.g., whether the cable is supposed to be strung in the air or underground, whether rodent protection is required). The two most popular types of coaxial cabling are used with Ethernet networks.
Application
In the midst of the 1920s, coax was applied to telephone networks as inter-office trunks. Rather than adding more copper cable bundles with 1500 or 1000 pairs of copper wire and cable in them, it was possible to replace those big cables with much smaller coaxial cable.