3Com SuperStackII Switch 3900 Quick Installation Manual page 5

LEDs and Power-up Diagnostics
Your system runs diagnostic software at power up. This software verifies
that every component in the system is operating correctly. If any
component fails during power-up diagnostics, the system either fails to
power up or, for the Switch 3900, it prevents faulty modules from coming
online.
For diagnostic messages, view the system display in the Administration
Console (if you have connected the system to a workstation).
For the Switch 3900, when the system comes up, verify which modules, if
any, have failed diagnostics by checking the module LEDs.
The system and port LEDs are described in Table 3.
Table 3 System and Port LEDs
LED Name Type
Power — System
power
Fault — System
fault
Pckt Packet Port
activity
Stat Status Port
link
Color
Indications Description
Green The system is powered up.
No light The system is powered down.
Yellow The system has failed diagnostics or
some other operational error has
occurred.
Blinking Diagnostic software is not running.
yellow
No light The system is operational.
Yellow Data is passing through the port.
Blinking Data is passing through the port.
yellow
No light Data is not passing through the port.
Green The port is online.
Blinking The port is online but disabled.
green
No light The port is off-line.
Quick Installation Guide 5