1-8Checking for Correct OperationAfter you power on the switch, it automatically performs a power-on self-test (POST). During POST, thePower LED on the front panel of the switch flashes green.When POST is complete, the Power LED turns green. If the Power LED turns yellow after POST, itmeans that POST failed and the switch has entered fail-safe mode.The following summarizes the possible colors for the Power LED after POST.Table 1-4 Summarizes the possible colors for the Power LED after POSTStatus MeaningGreen The unit is powered on and ready for use.Yellow Power-on self-test or loop back test failed. The switch is in fail-safe mode.This can happen if a port or ports fail when the switch was powered on.OffThe unit is not receiving power.z Verify that the power cord is connected correctly, and then try powering onthe switch againz If the switch still does not operate, contact your 3Com network supplierIf POST fails, try the following:z Power off the switch, and then power it on again. Check the Power LED and see if POST wassuccessfully completed.z Reset the switch. See Resetting to Factory Defaults.Resetting the switch to its factory default erases all your settings. You will need to reconfigure the switchafter you reset it.If these do not resolve the issue:z Check the 3Com Knowledgebase for a solution. To visit the 3Com Knowledgebase Web site, startyour Web browser, and then enter http://knowledgebase.3com.com.z Contact your 3Com network supplier for assistance.Using SFP TransceiversThe following sections describe how to insert an SFP transceiver into an SFP slot.SFP transceivers are hot-insertable and hot-swappable. You can remove them from and insert theminto any SFP port without having to power down the switch.
