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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
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