Nortel Networks 70 Series manual Straight-Through and Crossover Cables

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Installation and Reference for the BayStack 70 Series 10/100 Ethernet Switches

Straight-Through and Crossover Cables

For two devices to communicate, the transmitter of each device must be connected to the receiver of the other device. The crossover function is usually implemented internally as part of the circuitry in the device. Computers and workstation adapter cards are usually media-dependent interface ports, called MDI or uplink ports.

Most hub and switch ports are configured as media-dependent interfaces with built-in crossover ports, called MDI-X or normal ports. Refer to the instructions in Chapter 3, “Installation,” for appropriate cable use and connection.

Figure B-1 illustrates a straight-through twisted-pair cable.

Transmit 1

2

3 Receive 6

MDI port

Twisted pairs

1Receive

3

6 Transmit

MDI-X port

2008.8

Figure B-1. Straight-Through Twisted-Pair Cable

Figure B-2 illustrates a crossover twisted-pair cable.

1

Receive

2

3 Transmit 6

MDI-X port

1Receive

3

6Transmit

MDI-X port

7666EA

Figure B-2. Crossover Twisted-Pair Cable

B-2

206375-A

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Contents Installation and Reference for Copyright 1999 Nortel Networks Iii Restricted Rights Legend Statement of ConditionsNortel Networks NA Inc. Software License Agreement 206375-A Contents Chapter Troubleshooting Figures 206375-A Tables Xii Preface PurposeAudience Hard-Copy Technical ManualsHow to Get Help Technical Solutions Center Telephone NumberPage BayStack 70 Series 10/100 Ethernet Switches Overview Chapter IntroductionPhysical Description Front PanelFront Panel of the BayStack 70-8T 10/100 Ethernet Switch RJ-45 10BASE-T/100BASE-TX Ethernet Ports LEDs Description of Switch and Port Status LEDs Type Label Color Activity DescriptionRear Panel of the BayStack 70-24T 10/100 Ethernet Switch DC Power Adapter Features MAC Address QuantitiesModel MAC Addresses in Information Table Buffer Sizes Model Buffer SizeExternal Power Adapters Model External Power AdapterPage Chapter Network Configuration Benefits of Using Switching TechnologyTypes of Ethernet Switches Desktop Switching BeforeSegment Switching Before After Extending a Network Bridging from 10BASE-T to 100BASE-TX Networks Bridging 10 Mb/s Networks to 100 Mb/s NetworksPower Workgroups Power Workgroup ConnectionsChapter Installation Package ContentsPower Specifications Operating EnvironmentInstalling the Switch Set the switch on a desktop or any other flat surfaceAttach any additional devices to the ports in your switch Connecting Devices to the Switch Installing the Switch in a RackConnecting Power Verifying Installation Checking the Diagnostic Displays BayStack 70-24T 10/100 Ethernet Switch LED DisplayDescription of Switch and Port Status LEDs Page Chapter Troubleshooting Using the LED DisplayPage Appendix a Technical Specifications Product SpecificationsTable A-1 Technical Specifications Physical Specifications Environmental SpecificationsElectromagnetic Emissions Safety Agency Approvals Performance SpecificationsElectromagnetic Susceptibility Page 10BASE-T/100BASE-TX UTP Cable Appendix B Cables and ConnectorsTable B-1 RJ-45 Connector Pin Assignments RJ-45Straight-Through and Crossover Cables Figure B-1. Straight-Through Twisted-Pair CableIndex NumbersIndex-2