1275T / 1285T Series
Digital Clock Display
Page - 14
Revision 1.0
OPERATION
How does the transition from DST end?
Let's say that DST ends at 2:00 am local time and DST is one hour ahead of standard time:
DST End Transition
Local time
HH:MM:SS
DST or normal?
Comments
00:59:59
DST
01:00:00
DST
01:00:01
DST
...3556 seconds from 01:00:02 to 01:59:57 daylight saving time not shown...
01:59.58
DST
01:59.59
DST
01:00:00
Normal
Time is turned back to normal
01:00:01
Normal
...3556 seconds from 01:00:02 to 01:59:57 standard time not shown...
01:59.58
Normal
01:59:59
Normal
02:00:00
Normal
02:00:01
Normal
Table 4-2: DST End Transition
Note that local time between 1:00:00 and 1:59:59 actually is repeated twice this day, first during DST
time, then clocks are turned back one hour to normal time, and the hour is repeated during standard
time and therefore this day has 25 hours (instead of 24 hours). To avoid confusion when referring to
time within this hour, it is important to tell whether it happened before or after the change back to
normal time. For further information about daylight saving time in your area consult the web page
http://www.timeanddate.com/time/aboutdst.html
Because of the variation of daylight saving time rules throughout the world, the 1275T/1285T has
several registers to allow the user to set the DST rules for their region. There is a set of DST registers
for the LTC and each of the video outputs. For the sake of simplicity in the manual only the registers
for the LTC DST will be described.
The
DZ
menu item, allows you to configure the daylight saving time rules applied to the displayed time.
When in
DZ
menu, the 6 numeric displays show “DST”, and the alphanumeric display flashes with the
sub menu item to indicate that there is another level of menus. Use the
ITEM
key to move through the
list of available IC sub menu items. Once you have chosen the desired sub menu item, press the
SELECT
key to enter the bottom menu level.
The following section gives a brief description of the menu items available when you enter the
DZ
menu
item. Sections 4.3.3.1 onwards provide detailed descriptions of the
DZ
sub-menus. The tables in these
sections are arranged in an indented structure to indicate the path taken to reach the control. Menu
items or parameters that are underlined indicate the factory default values.
