Transmission Media

Chaiporn Jaikaeo

Department of Computer EngineeringKasetsart University

01204325 Data Communications and Computer Networks

Based on lecture materials from Data Communications and Networking, 5th ed.,Behrouz A. Forouzan, McGraw Hill, 2012.

Revised 2019-08-12

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Outline•Guided media

◦ Copper◦ Optical fiber

•Unguided media

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Physical Layer

Frame

from Data Link to Data Link

Frame

01001011 01001011

Transmission medium(bits)

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Classes of Transmission Media

Guided Media: Copper Media

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Twisted-Pair Cable

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UTP – Unshielded Twisted Pair STP –Shielded Twisted Pair

UTP and STP Cables

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Categories of UTP/STP Cables

Category Bandwidth Digital/Analog Use

1 very low Analog Telephone2 < 2 MHz Analog/digital 4Mbps token ring3 16 MHz Digital 10-100 Mbps Ethernet4 20 MHz Digital 16 Mbps token ring5 100 MHz Digital 100 – 1000 Mbps Ethernet

5E 100 MHz Digital 100 – 1000 Mbps Ethernet6 250 MHz Digital 1 – 10 Gbps Ethernet

6A 500 MHz Digital 1 – 10 Gbps Ethernet7 600 MHz Digital 10 Gbps Ethernet

7A 1000 MHz Digital 40-100 Gbps Ethernet

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RJ – Registered Jack

UTP Connectors

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Coaxial Cable

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RG – Radio Guide

Categories of Coaxial Cables

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BNC Connectors•Bayonet Network Connector

◦ aka. Bayonet Neil-Concelman

•Used with coaxial cables

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UTP and Coaxial Performance

www.ti.com/lit/an/sboa123/sboa123.pdf

Guided Media: Optical Media

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Optical Fiber•Based on physics of light

Image from Wikipedia

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Optical Fiber

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Propagation Modes

Multi-mode,step index

Multi-mode,graded index

Single-mode

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Fiber Types

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Fiber Construction

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Fiber-Optic Cable Connectors

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Optical Fiber Performance

Unguided Media

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Unguided Media: Wireless• Transport electromagnetic waves without using a physical

conductor◦ Radio Waves◦ Microwaves◦ Infrared

•Often referred to as wireless communication

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Electromagnetic Spectrum

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Propagation Methods

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Bands

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Antennas

Omni-directional Antenna Unidirectional Antennas

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Wireless Transmission Waves

used for multicast/broadcast communications, such as radio and television

used for unicast communication such as cellular telephones, satellite networks,and wireless LANs

used for short-range communication in a closed area using line-of-sight propagation

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Summary•Guided media serve as conduits for signals to propagate•Copper media carry electrical signals •Optical fibers carry optical signals•Unguided media allow signals to propagate without any

cable