Network cable is connected from a network device (such as a computer) to another network device, it is the basic component of the network. In our common LAN, network cable is used with a variety of types. Under normal circumstances,generally a typical local area network is not use a variety of different types of network cable to connect to the network device.In a large network or WAN in order to put together the different types of network connections will use different kinds of network cable.Among the many types of network lines, use which variety network cable according to the network topology, the network architecture standards and transmission speeds to choose.Understand the types and characteristics of the cable, to design and construction of the network for us is very important, Let’s discuss some categories by what kind of cable and their technical characteristics:
Lan Cable/Twisted Pair:
Twisted Pair divided shield (Shielded Twisted Pair, called STP) and unshielded (Unshielded Twisted Pair, called UTP).The shield refers to the inside line wrapped with a layer of metal mesh outside,Outside the shield is insulated jacket, the shield can effectively isolate the interference of external electromagnetic signals.
UTP is the one of the most frequently lines used in LAN,this cable wrapped eight signal lines inside of the plastic insulation sheath.They are two line intertwined together, total four pairs. Twisted intertwined with each other is to use an electromagnetic field generated by the current role of copper in the adjacent lines offset interference and reduce interference from the outside world. When the factory made the network cable, will remark the categories on the jacket,like cat3, cat5e,cat6,cat7 and so on.
STP is using a metal shield to reduce the external electromagnetic interference (EMI),when the shield is properly grounded, it can change the received electromagnetic interference signal into the current signal, and reverse with the twisted-pair. STP is generally used in susceptible to electromagnetic interference and radio frequency interference environment.
Fiber Optic Cable:
Fiber Optic Cable transmit signales in the form of light pulses, so is also based on glass or plexiglass material.It consists of fiber core, cladding and protective sleeve composition. The greatest feature of fiber is conducting optical signal,for it is not subject to outside electromagnetic signals interference, the signal decay rate is very slow, so the signal transmission distance is much farther than lan cable. Fiber optic cable is so popular at network word, but the cost is also expensive, so as usual, used in large lan. But with the fiber cost down, fierb optic cable will be used more and more.
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