Allied Telesis AT 8000/8POE - Manual (Page 46)

Chapter 3: Basic Switch Parameters
46 Section I: Using the Menus Interface
c. Type S to choose Set Time Zone.
The following message is prompt is displayed:
Select time zone>
d. Type the number that corresponds to the time zone you want.
If you selected a time zone that observes daylight saving time, the
following prompt is displayed:
Enable or Disable Daylight Saving (E/D)>
e. Type D to disable the daylight saving time or E to enable it.
Note
You must set the time zone in order to display the daylight saving
time option. If the time zone you previously selected is located in
DST area, you can set this anytime.