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In Computer Network, the transmission media is a channel between sender and receiver. The data from sender is sent to receiver through transmission media. The transmission media is categorized in following two types:
In Guided media, signals are transmitted through a physical path. The features of guide media are high speed and security. Guided media also known as Wired or Bounded transmission media. There are three types of Guided media:
1. Twisted PairTwisted pair cable is made up of two insulated wires twisted with each other. One wire carries the signal from source to destination and the other wire is for ground reference. Twisting is done to avoid the exterior electromagnetic interference. It is the most widely used transmission media. Advantages of Twisted pair cable:
Disadvantages of Twisted pair cable:
Applications of Twisted Pair Cables:
Types of twisted pair cableThere are two types of twisted pair cables:
Unshielded Twisted-pair cableUnshielded twisted pair cable is widely used in telecommunications. Unshielded Twisted pair (UTP) cable is categorized as follows: Category 1 UTP: Mostly used in telephone lines as it supports only low-speed data.Category 2 UTP: It supports upto 4Mbps.Category 3 UTP: It supports upto 16Mbps.Category 4 UTP: It supports upto 20Mbps. It can also be used for long-distance communications/ Category 5 UTP: It supports upto 200Mbps. Advantages of Unshielded Twisted-Pair Cable
Disadvantages of Unshielded Twisted-Pair Cable
Shielded Twisted-pair cableShielded twisted pair cable contains the metal foil surrounding the twisted copper wires to avoid external interference. Advantages of Shielded Twisted-Pair Cable
Disadvantages of Shielded Twisted-Pair Cable
2. Coaxial cableCoaxial cable has a centre conductor enclosed in a insulating cover, which in turn is enclosed in a metal foil shield. The whole cable is covered in a plastic cover. The metal foil shield protects against the noise. As the name suggests, it consists two conductors parallel to each other. The inner conductor is made up of copper and the outer conductor is made up of copper mesh. These two conductors are separated by insulating cover. The inner centre conductor is used for data transfer while the outer copper mesh conductor protects against the noise (Electromagnetic interference). Types of Coaxial CableBaseBand Transmission cable: It is used for transmission of single signal at high speed. It is used for digital transmission. Advantages Of Coaxial cable:
Disadvantages Of Coaxial cable:
3. Fiber-Optic CableFiber-Optic Cable is also known as optical-fiber cable. It is made of glass and the transmission of data is based on the concept of reflection of light through glass. In fiber optic cable, the optical fibers are coated in plastic. These optical fibers send the data by pulses of light. The plastic coating protects the cable from temperature, electromagnetic inference and other types of wiring issues. Components of a fiber optic cable: Core: The core of the fiber optic cable contains optical fibers and is responsible for data transmission in form of light pulses. Cladding: The core is enclosed in a layer of glass and this layer is called cladding. The main use of cladding is to reflect the light so that the light can be transmitted from source to the destination through reflection. Jacket: The jacket is the outer layer of fiber optic cable which is made up of plastic and the whole purpose of jacket is to protect the cable. Coaxial cable Propagation Modes: Multimode: Multiple light sources moves through different paths inside coaxial cable. Multiple data transmission simultaneously. Singlemode: Light moves in a single path close to horizontal of the cable. Advantages of fiber optic cable:
Unguided media does not use physical medium to transmit the data from source to destination. We already know that the Guided media uses physical medium such as cables and wires to transfer the data from source to destination. However unlike guided media, the Unguide media uses air as a transmission medium to transfer the data. Thus, it is called wireless transmission media. The unguided media uses an antenna for transmitting and receiving the data in form of electromagnetic waves. There are certain areas where it is very difficult or not possible to install the cables and wires such as hill areas, in these areas wireless data transfer is very much required.
1. Microwave transmissionIn microwave transmission, the range of frequency of electromagnetic waves lies somewhere between 1-300GHz. Microwave transmission is of two types:
Terrestrial Type Microwave TransmissionIn this type of microwave transmission, both the sender and receiver antennas are in direct sight with each other.
Advantages of Terrestrial type microwave transmission:
Disadvantages of Terrestrial type microwave transmission:
Satellite type microwave transmissionThis type of communication uses the satellite antenna for communication. The sender antenna sends the signal to the satellite antenna which is revolving around the earth at a known height. The satellite antenna then amplifies the received signal and sends it to the receiver antenna. Advantages of Satellite type transmission:
Disadvantages of Satellite type transmission:
2. Radio Transmission
Advantages of Radio Transmission:
Disadvantages of Radio Transmission:
3. Infrared Transmission
Advantages of Infrared Transmission:
Disadvantages of Infrared Transmission:
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