3Com 3CR17662-91, 3CR17661-91, 3CR17660-91 Color Indicates, Mode LED, 10/100/1000BASE-T Port LEDs

18CHAPTER 1: INTRODUCING THE SWITCH 4200G FAMILY

Table 4 Status Display (continued)

Display	Mode LED Color	Description
Rotating bar segment	Mode LED flashing green	Software download in progress.
Flashing “F”	Mode LED steady red	Fan failure detected.
Flashing “t”	Mode LED flashing red	Switch is too hot; temperature is critical.
“C”	Mode LED green or yellow	Switch is clustered Commander unit.
“c”	Mode LED green or yellow	Switch is clustered Candidate unit.
“S”	Mode LED green or yellow	Switch is clustered Slave unit.
“1”	Mode LED green or yellow	Switch is un-clustered.

LEDs Table 5 lists LEDs visible on the front of the Switch, and how to read their status. For information on using the LEDs for problem solving, see “Solving Problems Indicated by LEDs” on page 54.

Table 5 LED Behavior

LED	Color	Indicates
PWR LED
	Green	The Switch is powered-up and operating normally.
	Green flashing	Self Test (POST) or Software Download is in progress.
	Yellow flashing	One or more ports have failed POST.
	Red	The Switch has failed its Power On Self Test.
	Off	The Switch is not receiving power or there is a fault with the
		Power Supply Unit.
Mode LED
Speed	Green	10/100 Port Speed and Activity, Gigabit SFP Status and
		Activity, or Stack Status and Activity.
Duplex Yellow		10/100 Duplex and Activity, Gigabit SFP Duplex and
		Activity, or Stack Activity.
10/100/1000BASE-T Port LEDs
Speed	Green	A high speed (1000 Mbps) link is present, blinking off for
		every packet received or transmitted.
	Yellow	A low speed link is present, blinking off for every packet
		received or transmitted.
	Yellow Flashing	The port has failed POST.
	Off	No link is present.