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Wires (Conducted or guided media ) |
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use a conductor such as a wire or a fiber
optic cable to move the signal from sender to receiver |
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Wireless |
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Transmission medium just means the physical
materials that are used to transmit data between computers. |
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Examples: |
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twisted pair wires |
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coaxial cables |
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Fiber optic |
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Consists of two insulated copper wires arranged
in a regular spiral pattern to minimize the electromagnetic interference
between adjacent pairs. |
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Often used at customer facilities and also over
distances to carry voice as well as data communications. |
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STP (shielded twisted pair) |
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the pair is wrapped with metallic foil or braid
to insulate the pair from electromagnetic interference |
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Inexpensive and readily available |
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Flexible and light weight |
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Easy to work with and install |
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Susceptibility to interference and noise |
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Attenuation problem |
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For analog, repeaters needed every 5-6km |
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For digital, repeaters needed every 2-3km |
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Provides higher capacity then twisted pair. |
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Consist 2 wires – first copper wire surround by
insulator. Second wire is metallic cylinder called as shield. |
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Higher bandwidth |
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Can be tapped easily |
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Much less susceptible to interference than
twisted pair |
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High attenuation rate makes it expensive over
long distance |
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Bulky |
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A technology that uses glass (or plastic)
threads (fibers) to transmit data. A fiber optic cable consists of a bundle
of glass threads, each of which is capable of transmitting messages modulated
onto light waves. |
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Relatively new transmission medium used by
telephone companies in place of long-distance trunk lines. |
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greater capacity |
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smaller size and lighter weight |
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lower attenuation |
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immunity to environmental interference |
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expensive over short distance |
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requires highly skilled installers |
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adding additional nodes is difficult |
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Notes