3Com 3C16987A manual Color, Indicates, Port Status LEDs, Unit LEDs, Power/Self Test LED

14CHAPTER 1: INTRODUCING THE SWITCH 3300 SM

Table 3	LED behavior
LED	Color	Indicates
Port Status LEDs
Packet	Yellow	Packets are being transmitted/received on the port.
	Off	No packets are being transmitted/received on the
		port.
Status	Green	A link is present, and the port is enabled.
	Green flashing	A link is present, but the port is disabled.
	Off	No link is present.
Unit LEDs
1–8	Green	The Switch forms a stack with other Switch units;
		the LED indicates the position of the Switch in the
		stack and that a link is present. Note that although
		there are eight LEDs, only four Switch units can be
		stacked at present.
	Off	The Switch is stand-alone.
Power/Self Test LED
	Green	The Switch is powered-up.
	Green flashing	The Switch is either downloading software or is
		initializing (which includes running a Power On Self
		Test).
	Yellow	The Switch has failed its Power On Self Test.
	Off	The Switch is not receiving power.