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3Com 5108M-TP Channel Select Switch Settings, 1 - 8 ONline Ethernet 10BASE-T Module User’s Guide

Models: 5108M-TP

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The Off position sets the Squelch level to low. When the Squelch level is set to low, the ports are able to receive weaker signals. Note that Low Squelch mode does not conform to the 10BASE-T standard. If you change the module's Squelch level to low, you must change the 10BASE-T Transceiver Squelch level to low also. Refer to the ONline Ethernet 10BASE-T Transceiver Installation Guide for information on setting the transceiver Squelch level.

On unshielded twisted pair cable, setting the Squelch level to low increases the achievable link distance by approximately 25% to 50%, but with the added risk of losing packets to impulse noise. Do not use Low Squelch mode if your network should experience too many illegally short packets (runts). This problem will occur if there is significant external noise around the link.

Setting the Squelch level to low in conjunction with shielded twisted pair wiring increases the achievable link distance without sacrificing noise immunity. Thus, there is no realdrawback in using Low Squelch on shielded twisted pair.

To gain the extended link distance achieved by using Low Squelch mode, you must use qualified data grade shielded twisted pair cable or qualified high performance unshielded cable. IBM Type 1 shielded cable (with an appropriate RJ45 to Type 1 connector), among others, meets this requirement. If you are unsure of the grade of twisted pair cable to use, set the Squelch level to high, or call 3Com for a list of qualified cables to use in extended distance applications.

Channel Select Switch Settings

The ONline Ethernet 10BASE-T Module is equipped with the technology to work with the ONline System Concentrator's unique TriChannel™ architecture. This feature allows you to assign the module to any of three channels (or none) on the ONline System Concentrator backplane. Refer to Chapter 1 in the ONline System Concentrator Installation and Operation Guide for a complete discussion of ONline's TriChannel architecture.

The channel select switch settings (switches 2 and 3) on dip switch SW3 let you select a channel. Switches 2 and 3 are factory set to On, therefore, the

1 - 8 ONline Ethernet 10BASE-T Module User’s Guide

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3Com 5108M-TP manual Channel Select Switch Settings, 1 - 8 ONline Ethernet 10BASE-T Module User’s Guide

Contents

ONline Ethernet 10BASE-T Module User’s Guide Document Number Printed March Model Number 5108M-TP 3Com Corporation118 Turnpike Road Southborough, MA U.S.A 508 FAX 508 Federal Communications Commission Notice Canadian Emissions RequirementsVDE Class B Compliance EN55022/CISPR22 ComplianceONline Ethernet 10BASE-T Module User’s Guide Restricted Rightsiv ONline Ethernet 10BASE-T Module User’s Guide Contents How to Use This GuideChapter 1 - Introduction Chapter 2 - Designing and Expanding the NetworkChapter 3 - Installing and Operating the Module Chapter 4 - TroubleshootingAppendix A - Specifications Appendix B - Technical SupportFigures viii ONline Ethernet 10BASE-T Module User’s Guide Tables Page How to Use This Guide AudienceStructure of This Guide Document Conventions ConventionIndicates ExampleRelated Documents A Caution. AA Warning. A Warning Wear eye3Com Documents Reference DocumentsPage 1 Introduction The ONline Ethernet 10BASE-T ModuleIndicators Figure 1-1. 10BASE-T Module Faceplate and ONline System Concentrator Introduction 1Dip Switches LED NameColor StateDip Switch SW1 Port Status Figure 1-2. 10BASE-T Module and Dip Switch LocationsDip Switch SW3 Crossover Mode, Channel Select, Squelch SwitchSwitch Setting DefaultCrossover Mode Switch Squelch Mode SwitchSwitch Switch SettingChannel Select Switch Settings 1 - 8 ONline Ethernet 10BASE-T Module User’s GuideDip Switch SW6 Link Integrity Channel SelectionSwitch SwitchRelated Features LED and Channel VerificationSwitch Switch SettingChannel Configuration The ONline Ethernet Network Management ModuleLED State Table 1-6. Channel Check Codes1 - 12 ONline Ethernet 10BASE-T Module User’s Guide 2 Designing and ExpandingtheNetwork Designing and Expanding the Network 2Understanding the General Rules Basic Network RulesRule DefinitionRecommendations/Notes Table 2-1. Seven Basic Network RulesTable 2-1. Seven Basic Network Rules Continued RuleDefinition Recommendations/NotesRule DefinitionRecommendations/Notes The fiber link distancesLAN Equivalence LAN ProductEquivalent Distance metersFiber Backbone, Twisted Pair To-The-Desk Table 2-2. LAN Product Equivalent Distances ContinuedLAN Product EquivalentFiber Backbone, Twisted Pair To-The-Desk Example Figure 2-1. Sample Configuration Distance Calculation Cable Gauge Supports Link Distances Up To22 .6mm 150mTwisted Pair Backbone, Twisted Pair To-The-Desk Figure 2-2. Unshielded Twisted Pair NetworkRedundant Links Figure 2-3. Redundant Twisted Pair ConfigurationTo set redundancy between two 10BASE-T Modules, connect two links between the modules. The redundant link must be connected to a port on the same 10BASE-T Module as the primary link. Use a crossover adapter between each link unless you choose to uncross port 8 on one of the modules to make the connection. Refer to Chapter 1 for information on using crossover mode. Then use the SET PORT slot.port MODE REDUNDANT slot.port command to specify which port is the primary link and which is the backup link Patch Panels 2 - 14 ONline Ethernet 10BASE-T Module User’s Guide3 Installing and Operating the Module Precautionary ProceduresUnpacking Procedures Installation ProceduresFigure 3-1. Installing a 10BASE-T Module Figure 3-2. 10BASE-T Module Cable Connection 4 Troubleshooting TroubleshootingTroubleshooting With the Status LEDs TroubleshootingProblem IndicationTroubleshooting ProblemLED State IndicationTroubleshooting ProblemLED State IndicationTroubleshooting With the Activity LEDs Possible ProblemSolutions TroubleshootingTechnical Assistance A Specifications ONline Ethernet 10BASE-T Module SpecificationsElectrical Specifications Environmental Specifications Mechanical SpecificationsGeneral Specifications Twisted Pair Connectors and Cables Twisted Pair ConnectorsTwisted Pair Cables Figure A-1. RJ45 Connector Pin-outsConnecting Twisted Pair Cables Page B Technical Support On-line Technical SupportSupport from Your Network Supplier Email Technical SupportWorld Wide Web Site Support from 3Com Accessing the 3Com MIB Returning Products for Repair3Com Technical Publications Page Index Numerics