20 CHAPTER 1: INTRODUCING THE SUPER STACK 4 SWITCH 5500 F AMILYUnit LED The Unit LED is a seven segment display visible on the front of the Switch.The Unit LED can be used to diagnose hardware faults, display POST testID, display Stack ID, display PoE utilization and software upgradeinformation. For information on using the Unit LED for problem solving,see “Solving Problems Indicated by LEDs” on page 78.LEDs Table 5 lists LEDs visible on the front of the Switch, and how to read theirstatus according to color. For information on using the LEDs for problemsolving, see “Checking for Correct Operation of LEDs” on page 40.Table 5 LED behaviorLED Color Indicates10/100/1000BASE-TX Port LEDsSpeed Green A high speed (1000 Mbps) link is present, blinking offfor every packet received or transmitted.Yellow A low speed (10/100 Mbps) link is present, blinkingoff for every packet received or transmitted.Yellow flashing The port has failed POST.Off No link is present.Duplex Green Full duplex, blinking off for every packet received ortransmitted.Yellow Half duplex, blinking off for every packet received ortransmitted.Yellow flashing The port has failed POST.Off No link is present.PoE Green Power is being delivered to the port.Green flashing Port power has exceeded limit or is unable to supplypower due to unit being over budget.Yellow PoE error, no power supplied on port.Yellow flashing The port has failed post.Off No power is being delivered.10/100BASE-T/TX Ports LEDSSpeed Green A high speed (100 Mbps) link is present, blinking offfor every packet received or transmitted.Yellow A low speed (10 Mbps) link is present, blinking off forevery packet received or transmitted.Yellow flashing The port has failed POST.Off No link is present.
