3Com 5108M-TP Twisted Pair Backbone, Twisted Pair To-The-Desk, Unshielded Twisted Pair Network

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Twisted Pair Backbone, Twisted Pair To-The-Desk

In constructing a twisted pair backbone, one additional configuration rule must be considered:

There can be no more than eight 10BASE-T Modules in the path between any two transceivers due to the Ethernet four-repeater rule (each 10BASE-T Module counts as a 1/2 repeater). You must add a bridge if you have more than eight 10BASE-T Modules serially connected.

The configuration in Figure 2-2 illustrates a possible unshielded twisted pair network using 22 gauge cable.

Figure 2-2. Unshielded Twisted Pair Network

Note that when connecting two concentrators with twisted pair cable, use port 8 on one of the 10BASE-T Modules and disable crossover mode for that port. This allows a direct connection to another 10BASE-T Module without the need for an intervening adapter. (Refer to Dip Switch SW3 (Crossover Mode, Channel Select, Squelch) in Chapter 1 for information on crossover mode and the crossover mode switch setting.)

Designing and Expanding the Network 2 - 11

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Contents ONline Ethernet 10BASE-T Module User’s Guide Ii ONline Ethernet 10BASE-T Module User’s Guide ONline Ethernet 10BASE-T Module User’s Guide Iv ONline Ethernet 10BASE-T Module User’s Guide Contents Installing and Operating the Module Figures Viii ONline Ethernet 10BASE-T Module User’s Guide Tables Page Audience How to Use This GuideStructure of This Guide Document Conventions Convention Indicates ExampleUsr/snm/agents Related Documents Reference Documents 3Com DocumentsPage ONline Ethernet 10BASE-T Module IntroductionIndicators BASE-T Module Faceplate and ONline System Concentrator Dip Switches Interpretation of the 10BASE-T Module LEDsLED Name Color State Indicates Dip Switch SW1 Port Status Dip Switch SW1 Settings and Interpretations Dip Switch SW3 Crossover Mode, Channel Select, SquelchSquelch Mode Switch Dip Switch SW3 Settings for Switches 1Switch Function Factory Switch Setting Default Off Crossover Mode SwitchChannel Select Switch Settings Switch Channel Selection Dip Switch SW3 Settings and Interpretations for Switches 2Related Features Dip Switch SW6 Settings and InterpretationsEnable Channel Check Codes LED State Channel ConfigurationPage Designing and ExpandingtheNetwork Basic Network Rules Understanding the General RulesRule Definition Recommendations/Notes Seven Basic Network RulesCertain LAN devices Seven Basic Network Rules LAN Equivalence LAN Product Equivalent DistancesLAN Product Equivalent Distance meters Fiber Backbone, Twisted Pair To-The-Desk Fiber Backbone, Twisted Pair To-The-Desk Example Sample Configuration Distance Calculation Maximum Link Distance on Twisted Pair Unshielded Twisted Pair High Squelch Low SquelchShielded Twisted Pair High Squelch Low Squelch IBM Type Unshielded Twisted Pair Network Twisted Pair Backbone, Twisted Pair To-The-DeskRedundant Links Redundant Twisted Pair ConfigurationPage Patch Panels Precautionary Procedures Installing and Operating the ModuleInstallation Procedures Unpacking ProceduresInstalling a 10BASE-T Module BASE-T Module Cable Connection Troubleshooting TroubleshootingTroubleshooting With the Port Status LEDs Troubleshooting With the Status LEDsTroubleshooting With the Port Status LEDs Troubleshooting With the Port Status LEDs LED Name Troubleshooting With the Activity LEDsTroubleshooting With the Port Activity LEDs Possible Problem Troubleshooting State SolutionsTechnical Assistance Electrical Specifications ONline Ethernet 10BASE-T Module SpecificationsEnvironmental Specifications Mechanical SpecificationsGeneral Specifications Twisted Pair Connectors Twisted Pair Connectors and CablesTwisted Pair Cables Figure A-1. RJ45 Connector Pin-outsConnecting Twisted Pair Cables Page On-line Technical Support Technical SupportSupport from Your Network Supplier Email Technical SupportWorld Wide Web Site Support from 3Com Returning Products for Repair Accessing the 3Com MIB3Com Technical Publications Page Index MIB, B-4