Computer Networks Topics: Twisted Pair and Fiber Optic Cable Submitted by: Charan Shekar (17411114) Tiasha Som (1741159) Ritika Sen (1741164)

Transmission Media Communication Media Wired / Guided Twisted Pair Coaxial Cable Optical Fiber Wireless / Unguided Radiowave Microwave Infrared In data communication terminology, a transmission medium is a physical path between the transmitter and the receiver i.e it is the channel through which data is sent from one place to another. R

Wired / Guided Media Features: It is also referred to as Wired or Bounded transmission media. Signals being transmitted are directed and confined in a narrow pathway by using physical links. Features: High Speed Secure Used for comparatively shorter distances R

Twisted Pair Cable R

Structure One wire is used to carry signals to the receiver and the other wire is used only as the ground reference. Wires are twisted in order to avoid interference due to crosstalk which may affect differently to both wires if they were parallel It consists of 2 separately insulated conductor wires wound about each other. Generally, several such pairs are bundled together in a protective sheath. They are the most widely used Transmission Media. R

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Types of Twisted Pair Cables Unshielded Twisted Pair (UTP) Shielded Twisted Pair (STP)

Unshielded Twisted Pair This type of cable has the ability to block interference and does not depend on a physical shield for this purpose. It is used for telephonic applications. Advantages: Least expensive Easy to install High speed capacity Disadvantages: Susceptible to external interference Lower capacity and performance in comparison to STP Short distance transmission due to attenuation R

Shielded Twisted Pair This type of cable consists of a special jacket to block external interference. It is used in fast-data-rate Ethernet and in voice and data channels of telephone lines. Advantages: Better performance at a higher data rate in comparison to UTP Eliminates crosstalk Comparitively faster Disadvantages: Comparitively difficult to install and manufacture More expensive Bulky C

Applications Telephone lines to provide voice and data channels. The DSL lines that are used by telephone companies to provide high data rate connection. Local Area Networks, such as 10-base-T and 100-base-T. C

Categories C

Connectors C

Optical Fibre Cable T

Optical Fiber It uses the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding. It is used for transmission of large volumes of data. T

Structure The outer jacket is made of either PVC or Teflon. Inside the jacket are Kevlar strands to strengthen the cable. Below is a plastic coating to cushion the fiber. The fiber is at the center of the cable it consists of cladding and core. T

Different Layers T

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Advantages 1.Higher Bandwidth 2.Less signal attenuation it needs repeater every 50km, where twisted and coaxial need it every 5km. 3.Immunity to electromagnetic interference (noise) 4.Resistance to corrosive materials. Glass is more resistance to corrosive material than copper 5.Light weight. Fiber cables are much lighter than copper cables 6.Greater immunity to tapping: copper cables create antenna effects that can easily be tapped T

Disadvantages 1.Installation and maintenance. It’s a new technology. Its installation and maintenance require expertise that is not yet available every where. 2.Unidirectional light propagation. If we need bidirectional , two fibers are needed. 3.Cost. The cable and the interfaces are more expensive than those of other guided media. If the demand of BW is not high , often use of optical fiber can not be justified T

Usage of Optical Fiber Cable T

Fiber Optic Cable Connectors

Propagation Modes C

Single and Multimode Multimode Multimode is so named because multiple beams from a light source move through the core in different paths Single Mode Single mode uses step-index fiber and a highly focused source of light that limits beams to a small range of angles, all close to the horizontal. The single-mode fiber itself is manufactured with a much smaller diameter than that of multimode fiber, and with substantially lower density C

Modes C

Types of Fibers Multimode Step-Index Fiber Density of core remains constant from the center to the edges. At the interface of the core and the cladding, there is an abrupt change to lower density which alters the angle of beam’s motion. “Suddenness of change” Multimode Graded-Index Fiber It has varying densities thus leading to less distortion in signal. Density is highest at the centre of the core and decreases gradually to its lowest at the edge. Single Mode Highly focused source of light that limits beams to a small range of angles, all close to the horizontal. C

Multimode, Graded Index Fiber Types Type Core Cladding Mode 50/125 50.0 125 Multimode, Graded Index 62.5/125 62.5 100/125 100.0 7/125 7.0 Single Mode C

QUESTIONS BASED ON THIS TOPICS SLNo. QUESTION MARKS 1. Define Transmission Media. 2 2. List the applications of guided media. 6 3. Discuss in detail about the physical description, application and transmission characteristics of the guided Media. 10 4. Explain the types of guided media with suitable diagrams. 5. Provide the classification of Transmission media. Explain in detail each one of them. RTC

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