1. Twisted Pair Cable :
Wires are twisted together in pairs. Each pair would consist of wire used for the positive data signal and a wire used for the negative data signal. Any noise that appears on positive/negative wire of the pair would occur on the other wire. Because the wires are opposite polarities, these are 180 degrees out of phase (180 degree or definition of opposite polarities). When the noise appears on the both wires, it cancels or nulls itself out at the receiving used.
There are two types of twisted pair cable –
- Shielded Twisted Pair Cable –
Twisted pair cables are most effectively used in system that uses a balanced line method of transmission. Cables with shield are called Shielded twisted pair cables and commonly abbreviated STP.
- Unshielded Twisted Pair Cable –
Cables without shield are called unshielded twisted pair cables or UTP. Twisting the wires together results in characteristics impedance for the cable. UTP cable is used on Ethernet.
2. Co-axial Cable :
Co-axial cable consists of two conductors. The inner conductor is contained inside the insulator with the other conductor weaves around it providing a shield. An insulating protective coating called a jacket covers the outer conductor. The outer shield protects the inner conductor from outside electrical signals. Distance between the outer conductor and inner conductor plus the type of material used for insulating the inner conductor determine the cable properties.
3. Optical Fiber Cable :
Optical fiber consists of thin glass fiber that can carry information at frequencies in the visible light spectrum. Typical optical fiber consists of a very narrow strand of glass called the cladding. A typical core diameter is 62.5 microns.
Typically cladding has a diameter of 125 minors. Coating the cladding is a protective coating consisting of plastic, it is called the jacket. The device generating the message has it in electromagnetic from (electrical signal). This has to be converted into light to send it on optical fiber cable.
Difference Between Twisted pair cable, Co-axial cable and Optical fiber cable
|Characteristics||Twisted pair cable||Co-axial cable||Optical fiber cable|
|Signal transmission||Takes place in the electrical form over the metallic conducting wires.||Takes place in the electrical form over the inner conductor of cable.||Takes place in an optical form over a glass fiber.|
|External magnetic field||Affected due to external magnetic field.||External magnetic field is less affected .||External magnetic field is not affected.|
|Cause of power||Power loss due to conduction and radiation.||Power loss due to conduction.||power loss due to absorption, scattering and bending.|
|Bandwidth||Twisted pair cable has low bandwidth.||Co-axial cable has moderately high bandwidth.||Optical fiber cable has very high bandwidth.|
|Electromagnetic interference(EMI)||EMI can take place.||EMI is reduced to shielding.||EMI is not present.|
|Installation||Easy installation.||Fairy easy installation.||Difficult to install.|
|Attenuation||In twisted pair cable has very high attenuation.||In co-axial cable has low attenuation.||In optical fiber cable has very low attenuation.|
|Data rate||Twisted pair cable supports low data rate.||Moderately high data rate.||Very high data rate.|
|Noise immunity||Twisted pair cable has low noise immunity.||Co-axial cable has higher noise immunity.||Optical fiber cable has highest noise immunity.|
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