Guided Transmission Media: In guided communication media, information is transmitted over a closed path like a physical wire. In this way, they are likewise called wired communication media or bound communication media. For example
- Twisted Pair Cable
- Coaxial Cable
- Optical Fiber
Types of Guided Media
Twisted Pair Cable
This cable is the most ordinarily used and is less expensive than others. It is lightweight, cheap, can be introduced effectively, and they support various types of network. Some significant points:
- Its frequency range is 0 to 3.5 kHz.
- Typical attenuation is 0.2 dB/Km @ 1kHz.
- The typical delay is 50 µs/km.
- Repeater spacing is 2km.
A twisted pair comprises of two conductors(normally copper), each with its own plastic incluation, bent together. One of these wires is used to convey signals to the receiver, and the other is used distinctly as a ground reference. The receiver uses the difference between the two. Notwithstanding the signal sent by the sender on one of the wires, interference(noise) and crosstalk may influence the two wires and create unwanted signals. On the off chance that the two wires are parallel, the impact of these unwanted signals isn’t something similar in the two wires since they are at various areas comparative with the noise or crosstalk sources. These outcomes a difference at the receiver.
Twisted Pair is of two types:
- Unshielded Twisted Pair (UTP)
- Shielded Twisted Pair (STP)
Unshielded Twisted Pair Cable
It is the most widely recognized sort of telecommunication when compared and Shielded Twisted Pair Cable which comprises of two conductors generally copper, each with its own colour plastic insulator. Identification is the reason behind coloured plastic insulation.
UTP cables comprise 2 or 4 pairs of twisted cables. Cable with 2 pair use RJ-11 connector and 4 pair cable use RJ-45 connector.
Shielded Twisted Pair Cable
This cable has a metal foil or twisted braided mesh covering which encases each pair of insulated conductors. The electromagnetic noise entrance is forestalled by a metal casing. Shielding likewise eliminates crosstalk
It has the same constriction as unshielded twisted pair. It is quicker than the unshielded and coaxial cable. It is more costly than coaxial and unshielded twisted pairs.
Coaxial is called by this name since it contains two conductors that are corresponding to one another. Copper is used in this as a center conductor which can be a solid wire or a standard one. It is encircled by PVC installation, a sheath that is encased in an external conductor of metal foil, braid, or both.
External metallic wrapping is used as a shield against noise and as the second conductor which finishes the circuit. The external conductor is additionally encased in insulating sheath. The outermost part is the plastic cover which protects the whole cable.
Here the most common coaxial standards.
- 50-Ohm RG-7 or RG-11 : used with thick Ethernet.
- 50-Ohm RG-58 : used with thin Ethernet
- 75-Ohm RG-59 : used with cable television
- 93-Ohm RG-62 : used with ARCNET.
Optical fiber is the innovation related to data transmission using light pulses traveling alongside a long fiber which is generally made of plastic or glass. Metal wires are liked for transmission in optical fiber communication as signals travel with fewer damages. Optical fibers are additionally unaffected by electromagnetic interference. The fiber optical cable uses the application of complete inside reflection of light. The fibers are designed to such an extent that they work with the propagation of light alongside the optical fiber relying upon the necessity of power and distance of transmission. Single-mode fiber is used for significant distance transmission, while multimode fiber is used for more limited distances. The external cladding of these fibers needs better protection than metal wires.
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