3com 4400 (3C17204) User Manual

connector that allows both the transmit and the receive fibers to be 
connected in the same space as an RJ-45 port.

Table 4 lists LEDs visible on the front of the Switch, and how to read their 
status according to color. For information on using the LEDs for problem 
solving, see “Solving Problems Indicated by LEDs” on page 58.

Table 4   LED behavior  

Green

The Switch is powered-up and operating normally.

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

or

A port has failed and has been automatically disabled. You 
can verify this by checking that the Port Status LED is quickly 
flashing Yellow. If a port fails the Switch passes its Power On 
Self Test and continues to operate normally.

Off

The Switch is not receiving power or there is a fault with the 
Power Supply Unit.

Packet Green

Full duplex packets are being transmitted/received on the 
port.

Yellow

Half duplex packets are being transmitted/received on the 
port.

Off

No packets are being transmitted/received on the port.

Status Green

A high speed (100 Mbps) link is present, and the port is 
enabled.

Green flashing A high speed (100 Mbps) link is present, but the port is 

disabled.

Yellow

A low speed (10 Mbps) link is present, and the port is 
enabled (not 4400 FX).

Yellow flashing A low speed (10 Mbps) link is present, but the port is 

disabled (not 4400 FX).

Yellow flashing 
(fast)

The port has failed and has been automatically disabled. The 
Switch passes its Power On Self Test and continues to 
operate normally even if one or more ports are disabled.

Off

No link is present.

DUA1720-3AAA07.book  Page 17  Wednesday, March 17, 2004  1:14 PM