Avaya DEFINITY Manual page 256

DLG System Administration
3. If you do not want to enter a second time zone, be sure DST Name is clear
and then skip to step 4.
If you do want to enter a second time zone that follows U.S. Daylight
Savings rules, under Daylight Savings Timezone Information,
type the name or abbreviation in the Name field as you did in step 2.
However, note the following conventions for this field:
4. Press
reappears.
6-34 Issue 3 May 2002
If you enter a name or abbreviation that is not in the table, then you
must also enter offset time and direction.
NOTE:
The system determines the time zone that appears to the right
of the Time field in the top line of the screen according to
what is entered in these fields and the current date and time.
If you type any value in this field, then you are setting an alternate
timezone that follows U.S. Daylight Savings rules.
If you want a second time zone but do not want U.S. Daylight
Savings rules to apply, then make sure the field is blank and
manually change the system clock on the appropriate date.
when you are done typing data. The Maintenance menu
ENTER