Allied Telesis AT-8550 - Manual (Page 245)

B-1
Appendix B
Troubleshooting
If you encounter problems when using the switch, this appendix may
be helpful. If you have a problem not listed here or in the “Release
Notes,” contact your local technical support representative.
LEDs
Power LED does not light:
Check that the power cable is firmly connected to the device and to
the supply outlet.
On powering-up, the MGMT LED lights yellow:
The device has failed its Power On Self Test (POST) and you should
contact your supplier for advice.
A link is connected, but the Status LED does not light:
Check that
❑ All connections are secure.
❑ Cables are free from damage.
❑ The devices at both ends of the link are powered-up.
❑ Both ends of the Gigabit link are set to the same
autonegotiation state.