Cabletron Systems SEHI100TX manual UTP Cable Speciﬁcations

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Chapter 3: Installation Requirements and Speciﬁcations

3.1.2UTP Cable Speciﬁcations

The device at the other end of the twisted pair segment must meet IEEE 802.3u 100BASE-T speciﬁcations. When connecting a 100BASE-TX Twisted Pair Segment to the SEHI twisted pair network ports and the EPIM-100TX module, the network must meet the following requirements:

Length

The IEEE 802.3u 100BASE-T standard requires that 100BASE-TX devices be capable of transmitting over a 100 meter (328 foot) link using Category 5 UTP wire.

Impedance

UTP cables typically have an impedance of between 85 to 110 ohms.

Jitter

Intersymbol interference and reﬂections cause jitter in the bit cell timing, resulting in data errors. A 100BASE-TX link must not generate more than

1.4ns of jitter. If the cable meets the impedance requirements for a 100BASE-TX link, jitter should not be a concern.

Crosstalk

Crosstalk is caused by signal coupling between the different cable pairs contained within a multi-pair cable bundle. 100BASE-TX transceivers are designed so that the user does not need to be concerned about cable crosstalk, provided the cable meets all other requirements.

Noise

Noise is caused by either crosstalk or externally induced impulses. Impulse noise may cause data errors if the impulses occur at very speciﬁc times during data transmission. Generally, the user need not be concerned about noise. If noise-related data errors are suspected, it may be necessary to either reroute the cable or eliminate the source of the impulse noise.

3-2	SEHI100TX User’s Guide

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Contents Intelligent Stackable HUB USER’S Guide SEHI100TX User’s Guide FCC Notice Cabletron SYSTEMS, INC. Program License Agreement United States Government Restricted Rights Contents Contents SEHI100TX User’s Guide Vii Chapter Introduction Using this ManualFollowing conventions are used throughout this document Document ConventionsRelated Manuals Getting HelpSehi Overview Chapter Sehi Features and OptionsSehi Features and Options Sehi FeaturesStackable Capabilities Optional 100BASE-TX and 100BASE-FX EPIMs Rack Mounting CapabilitiesRemote Network Management HubSTACK Interconnect Cable Requirements Chapter Installation Requirements SpecificationsCable Specifications UTP Cable Speciﬁcations Multimode Speciﬁcations for the EPIM-100FX Network Cable Lengths COM Port Requirements Network Port SpecificationsEnvironmental Requirements Operating SpecificationsPower Supply Requirements Agency Approvals Physical SpecificationsUnpacking the Sehi Chapter InstallationNvram Switch Location PRE-INSTALLATION CheckoutSEHI100TX-22 Tabletop or Shelf InstallationScrews Strain-Relief Bracket Rackmount InstallationRackmount Installation Installing the Sehi in the Rack Powering UP and Stacking the Sehi Repeat steps 3 through 6 until all SEH hubs are connected Install an EPIM-100TX or an EPIM-100FX as follows Installing the EPIM-100TX or the EPIM-100FXConnecting to Network Ports Chapter Connecting to the NetworkConnecting the Sehi to the Network Sehi Network Ports Connecting a UTP Segment to an EPIM-100TXPosition X crossed over RX+ TX+ Position = Not crossed over EPIM-100FX Port Connecting a Fiber Segment to the EPIM-100FXTesting the Installation Installation Test Chapter TroubleshootingUsing Lanview Using Lanview Epim 1 RCV LED Using the Reset ButtonSetting the Nvram Switch Chapter Local Management Keyboard Conventions Function Local Management Keyboard ConventionsManagement Terminal Setup Console Cable Conﬁguration Management Terminal Setup Parameters Sehi Local Management Accessing Local ManagementFeature Selection Screen Feature Selection ScreenCommunity Name Table Screen Community Name Table ScreenEditing the Community Name Field Configuration Configuration ScreenDisplays the IP address of the Sehi Setting the Subnet Mask Setting the IP AddressUsing the Port Enable Override Setting the Default GatewayTrap Table Screen Exiting the Conﬁguration ScreenExiting the Trap Table Screen 1 Conﬁguring the Trap TableSnmp Tools Screen Snmp Tools ScreenLets you retrieve MIB objects using Snmp protocol Getting the Next OID Setting an OIDGetting Individual OIDs Walking Through OIDs Viewing Multiple OIDsExiting the Snmp Tools Screen Stepping Through OIDsCycling Through OIDs Device Statistics Screen Device Statistics ScreenDisplays the number of errors due to misaligned packets Module Number Sequence Selecting the Appropriate Module/PortExiting the Device Statistics Screen Using the Enable Port CommandUsing the Disable Port Command EPIM-100TX Appendix a Epim SpecificationsEpim Specifications EPIM-100FX Appendix B Image File Download Using Oids Setting UP a Unix Workstation AS a Tftp Server Standard Local Download Table B-1 OIDs and Settings Numerics IndexIndex-2 Power Supply Cord