© 2007 Cisco Systems, Inc. All rights reserved. 1Valašské Meziříčí 21.04.2023

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