Twisted-Pair Cable

Computer NetworkComputer EngineeringMCA

One of the earliest guided transmission media is twisted pair cables. A twisted pair cable comprises of two separate insulated copper wires, which are twisted together and run in parallel. The copper wires are typically 1mm in diameter. One of the wires is used to transmit data and the other is the ground reference.

Reason for Twisting

All transmissions are prone to noise, interferences, and crosstalks. When the wires are twisted, some part of the noise signals is in the direction of data signals while the other parts are in the opposite directions. Thus the external waves cancel out due to the different twists. The receiver calculates the difference in the voltages of the two wires for retrieving data. Thus a much better immunity against noise is obtained.

Applications of Twisted-Pair Cables

  • In telephone lines
  • In DSL lines
  • In LANs

Types of Twisted–Pair Cables

There are two types of twisted pair cables −

  • Unshielded Twisted Pair ( UTP ): These generally comprise of wires and insulators.
  • Shielded Twisted Pair ( STP ): They have a braided wired mesh that encases each pair of insulated wires.

Categories of Twisted–Pair Cables

EIA has classified twisted pair cables into seven categories −

  • Category 1 − UTP used in telephone lines with data rate < 0.1 Mbps
  • Category 2 − UTP used in transmission lines with a data rate of 2 Mbps
  • Category 3 − UTP used in LANs with a data rate of 10 Mbps
  • Category 4 − UTP used in Token Ring networks with a data rate of 20 Mbps
  • Category 5 − UTP used in LANs with a data rate of 100 Mbps
  • Category 6 − UTP used in LANs with a data rate of 200 Mbps
  • Category 7 − STP used in LANs with a data rate of 10 Mbps
raja
Published on 24-Jul-2018 06:14:03
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