Allied Telesis AT-8550 - Manual (Page 246)

LEDs
B-2
Both sides if the Gigabit link must be enabled or disabled. It
the two are different, typically the side with autonegotiation
disabled will have the link LED list, and the side with
autonegotiation enabled will not list. The default
configuration for a Gigabit port is autonegotiation enabled.
This can be verified by entering the following command:
show port config
Switch does not power up:
All products manufactured by Allied Telesyn use digital power
supplies with surge protection. In the event of a power surge, the
protection circuits shut down the power supply. To reset, unplug the
switch for 1 minute, plug it back in, and attempt to power up the
switch.
If this does not work, try using a different power source (different
power strip/outlet) and power cord.