Post on 30-Mar-2015
© 2007 Cisco Systems, Inc. All rights reserved. 1Valašské Meziříčí 10.04.2023
Networking Media
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Objectives
Types of cables and connectors
Constructing and terminating twisted pair cables
Determining type of cable needed
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Cables and Connectors
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Cables and Connectors
Types of cables
Today Yesterday Tomorrow
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Twisted pair cables
Cables and Connectors
4 pairs of copper wires twisted together
UTP = Unshielded Twisted Pair
There is no shielding
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Twisted pair cables
Cables and Connectors
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Coaxial cable
Cables and Connectors
Center conductorShielding
• Used in TV and radio applications• Not used in computer networks any more
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Optical fiber cables
Cables and Connectors
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Optical fiber cables
Cables and Connectors
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Optical fiber cables
Cables and Connectors
Components of the puls start at the same time.
Here they arrive at the same time => good result.
Here they arrive at different times => bad result.
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Optical fiber cables
Cables and Connectors
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Optical fiber cables
Cables and Connectors
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Construct and Terminate Twisted Pair Cables Cross-over and straight through cables
Transmit pins on one device must be connected to receive pins on the other device.
Transmit pins
Receive pins
Device 1
Transmit pins
Receive pins
Device 2
There must be a crossing in the path.
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Construct and Terminate Twisted Pair Cables Cross-over and straight through cables
Transmit pins
Receive pins
PC
Transmit pins
Receive pins
Switch
No need of a crossing in the path.
A crossing is inside each switch.
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Construct and Terminate Twisted Pair Cables Cross-over and straight through cables
A crossing is inside each switch.
Transmit pins
Receive pins
Switch
Another crossing must be in the path.
Transmit pins
Receive pins
Switch
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Construct and Terminate Twisted Pair Cables Cross-over and straight through cables
Conclusion: There must be odd number of crossings in the whole path.
PC PC
PC
Switch
Switch
Switch
Like devices: Crossover cable
Unlike devices: Straight-through cable
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Construct and Terminate Twisted Pair Cables How to terminate UTP cables
The plug is plugged into the jack.
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Construct and Terminate Twisted Pair Cables How to terminate UTP cables
Two standards on plugs and jacks
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Construct and Terminate Twisted Pair Cables How to terminate UTP cables
Crossover cable: A – B
Straight-through cable: B – B(in Europe)
Remember: A for America
Straight-through cable: A – A(in America)
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Construct and Terminate Twisted Pair Cables How to terminate UTP cables
Hold the plug as if you wanted to insert it into the jack, and arrange the color pairs to correct color sequence.
Jack
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Construct and Terminate Twisted Pair Cables How to terminate UTP cables
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Construct and Terminate Twisted Pair Cables Cable testing
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Summary
Physical cabling media must conform to standards
Cabling best practices reduce attenuation and crosstalk