3Com EtherLink 3C985B-SX Installation And User Manual

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3Com EtherLink 3C985B-SX Installation And User Manual Manual pdf 27 page image

234 TroubleshootingThis chapter describes techniques for troubleshooting your NIC and correcting some types of problems. Thefollowing topics are covered: Instructions for performing detailed hardware diagnostics on the NIC Behavior of the NIC’s status LEDs How to resolve some common networking problems How to reach 3Com customer service and supportHardware Diagnostic UtilityDOS Diagnostics Internal/External Loopback Test (MS-DOS)An MS-DOS based diagnostic utility, TTP.EXE, is included on the CD-ROM. This utility is used for verifying thatthe NIC hardware is functional. It performs internal and external loopback tests and provides resulting pass/failinformation. Perform the DOS Diagnostics tests any time you wish to rule out or identify possible NIC hardwareproblems.To use the DOS Diagnostics utility, follow this procedure:1 Boot your system in clean MS-DOS mode rather than Novell NetWare.2 Disconnect the network cables on all NICs being tested.The loopback tests will not perform properly if the NIC is left connected to other devices.3 Connect a Cat. 5 UTP loopback cable to the NIC’s RJ-45 jack.A loopback cable can be constructed by connecting the following pins back to the single connector:NOTE: To use the DOS Diagnostics utility, you must boot your computer in clean MS-DOS mode, with noother plug-ins, add-ons, or resident programs installed.Pin 1Pin 2Pin 4Pin 5Pin 3Pin 6Pin 7Pin 8Category 5 Loopback Cable