Transmission media is a communication medium classified as twisted pair cabling in which two conductors of a single circuit are twisted together for improving electro magnetic compatibility. They are generally two types of transmission media in computer networks, Guided and Unguided media which used to connect any two devices or connect any device to a network physically. Also includes wireless media such as infrared waves,microwaves and radio waves(common type of wireless transmission media). The main function of transmission media is transporting data in the form of bits over a LAN.
How transmission media types in computer network works ?
Guided media is simply which we can see and touch in the real world situations and it contains an insulation layer for transferring data in baseband mode and broadband mode which is considered when one wants to establish a network with High speed.It is a physical medium through which signals/data is transmitted in a narrow pathway. Higher data transmission rate of a signal can be achieved with the greater bandwidth of transmission medium.
Unguided media is completely reverse to it which a user cannot see and touch network connection as it creates a wave forms, Hence it can be considered as wireless transmission media. The major difference between guided and unguided is the transmission speed.
The guided transmission media are guided along solid medium like transmission line. on the other side , Antenna helps in achieving transmission and reception in unguided transmission that does not provide a physical path for signal transmission. Choice of transmission media depends on factors like distance, susceptibility to interference and bandwidth requirements.
Types of Transmission media in computer network
Transmission media or communication in compute networks is generally a process of sending information from a source to a receiver in the form of electromagnetic signal waves. Its a system that meditates the propagation of signals for telecommunication purpose. Triaxal cable is expensive type of transmission media in whole guided and unguided media categories.
In many cases , communication is in the form of electromagnetic waves. Many different types of transmission media are used as communication channel. It is placed beneath the physical layer as it operates with various physical elements.
Guided media is a physical link between the transmitter and the receiver which is sensitive to external interference includes cables like twisted pair , fiber optic and coaxial cable which guides the waves /light signals along a physical path and preferred for shorter distances.
Unguided transmission media defines the path without the use of physical medium for data transmission using radio waves or micro waves.Types of unguided media are satellite communications, light waves , radio waves, infrared signals and microwaves. We are going to discuss one by one with detailed explanation
Twisted pair cable :
This type of cable has a pair of mostly (8) insulated copper wires together twisted for the purpose of cancelling out electromagnetic interference from other wire pairs of external sources. Two wires are generally twisted together forming 4 pairs from total 8 wires as to cancel the interference with the help of each pair because whenever each wire from any pair is reacting to any interference , the other wire which paired automatically helps in mostly reducing the interference as both these wires are oppositely wired. Generally frequency ranges from 0 to 3.5KHz for twisted pair cable.
The type which we mostly preferred in organizational networks is UTP (unshielded twisted pair) which not shielded but bundled togther in a protective sheath.. Even though it has no proper proper protection from external sources in still helps in reducing interferences but less interms of STP(shielded twisted pair) . This STP has extra metal shield on the top of plastic cover which makes it bulky but helps in reducing interference from external sources but also provides extra immunity. UTP is mostly preferred in ethernet networks whereas STP used in high speed networks which consists of foil shield to block external interference and with the additional layer of outer covering, STP most frequently used in extreme cold climates.
UTP categories are ranged from CAT1 , CAT2 and so on till CAT7 where each category has its own speed from low to high. From CAT4 to CAT5 there has been tremendous increase in the speed from 16mbps to 100mbps. Further CAT5e to CAT7 speed got jumped rapidly to 10Gbps. 100Mbps and 10Gbps speeds are termed as FastEthernet and GibabitEthernet respectively.
Advantages of using twisted pair are
- They are easy to work with because they are enclosed inside a protective coating.
- Cheaply available
- This twisted cable allows greater data transmission rate with the insulation it comes with.
Disadvantages of twisted pair are
- Only works better for short ranges
- Only available with low data rate
Coaxial cable :
The core here specifically made of copper with a metallic shield and other components which are used to block signal interference. In simple , it is made of PVC/Teflon and two parallel conductors insulated separately.Most of the coaxial cables also have any jacket or insulating outer sheath.
Mostly we see coaxial usage by tv companies to connect their satellite antenna facilities to customer homes and businesses. It is less susceptible to electromagnetic interference than other type of cables. Due to its dimensions , Coaxial differs from other shielded cables which is used to carry high frequency electric signals with low losses.
As coaxial cable comes with protection of multiple components like , The outer most layer it has is plastic cover beneath that we have insulator and a outer conductor shield below which protects another insulator that has main inner conductor. All these protection layers resulted in less interference which internally helps in gaining more immunity and carries high frequency electrical signals without any major loss.It is widely used transmission media in many sectors because of its high bandwidth and less cost.
Advantages and disadvantages of coaxial
- Improves shield effectiveness and helps in reducing signal weakness
- They are used in high frequency applications.
- Bandwidth is more when compared to twisted pair cable.
- Coaxial cable cost is less and has less interference when compared to twisted pair cable.
- Coaxial cables are not effected by any electromagnetic interference.
Disadvantages of coaxial cable are
- They are expensive to install because of its overall protection which make them bulky, stiff and thick.
- Grounding is necessary and also has few security issues.
- Single cable failure can disturb the entire network and thus does not support high speed transmission.
- coaxial cable can limit its usage in certain applications.
Optical fiber cable :
This optical fiber cable is one of the important transmission media used heavily in todays time because of its range and the form it uses. Generally , optical fiber cable transfers digital data signals in the form of light ranging distance across hundred of miles and they generally have a core surrounded by a transparent cladding material with a lower index of refraction. They are used to transmit internet communications , cable television signals and telephone signals by telecommunications companies.
Optical fibre cable usually has protection of outer jacket as the top most layer beneath which has series of protected layers starting from strength member, coating and cladding to the inner most core.In todays time , we have two common types of optical fiber cable they are Single mode fiber(SMF) and Multi mode fiber(MMF). Both SMF and MMF has step index and graded index respectively.It is also known as fiber optic cable and uses electric signals for communication. In fiber network bits are available in the form of light pulses unlike electric signals in copper cable network.
Advantages of using optical fiber cable are as follows
- It is light weighted and extremely small out of all the cables discussed above.
- Covers long distance communications and can carry huge amounts of data without using signal repeaters.
- Optical fibre has Low security risk.
- It provides faster data transmission than copper wires.
- Very much immune when compared to both coaxial and twister pair as it has resistance to electro magnetic interference.
Disadvantages of optical fiber are
- Because of different components used in protecting fiber cable , Cost is very much high.
- It is difficult to install and has dispersion.
- Optical fiber has delicate components which makes it very fragile.
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