Physical Transmission Media

Transmission Media- they consist of material or techniques capable of carrying one or more signals. Transmission media are of two types: Physical and wireless.

Physical Transmission Media:

  • Unshielded Twisted Pair Cable (UTP)
  • Shielded Twisted Pair Cable (STP)
  • Coaxial Cable
  • Fiber Optic Cable

UTP- This is the most popular and generally the best option for schools.

The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The disadvantage of UTP is that it may be susceptible to radio and electrical frequency interferences.

Unshielded Twisted Pair Connector: this connector is RJ-45. Its a plastic connector that looks like a large telephone- style connector. RJ stands for Registered Jack.

SHIELDED TWISTED PAIR CABLE (STP):


STP is suitable for environments with electrical interference, it help reduces noise which can degrade coomunication; however the extra shielding can make the cable bulky . STP is often used on network using Token Ring Topology.

COAXIAL CABLE :

Coaxial cabling has a single conductor as it center. A plastic layer provides insulation between the center conductor ad the braided mental shield. The metal shield help to block any outside interference from fluorescent lights, motors, and other computers . Its difficult to install, but its highly resistant to signal interference, it supports greater cable length between network devices than twisted pair. Two type of coaxial cable are: thick coaxial and thin coaxial.

FIBER OPTIC CABLE

Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials. It transmit lights rather than electronic signals thus eliminating electrical interference, this makes it suitable for areas that  contain large amount of electrical interferences. In addition it has the ability to transmit signals over much longer distance, carry more information at a faster speed than coaxial and twisted pair. More over cables are much thinner and light weighted.


 

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