Basic Operation Guide 2014/02

Figure 22 Menu interface with "user-defined" daylight time rule option
Before configuring a "User defined" daylight time rule, it is important to understand how the switch
treats the entries. The switch knows which dates are Sundays and uses an algorithm to determine
on which date to change the system clock, given the configured "Beginning day" and "Ending
day":
• If the configured day is a Sunday, the time changes at 2 am on that day.
• If the configured day is not a Sunday, the time changes at 2 am on the first Sunday after the
configured day.
This is true for both the "Beginning day" and the "Ending day."
With that algorithm, you should use the value "1" to represent "first Sunday of the month," and a
value equal to "number of days in the month minus 6" to represent "last Sunday of the month."
This allows a single configuration for every year, no matter what date is the appropriate Sunday
to change the clock.
140 Daylight Saving Time on HP Switches