D-Link DCS-2000 Manual page 80

Period Selector
Period selector provides you a precise way to choose the start time and the
end time of a new period. The end time should be larger than the start time.
After you give the correct start and end time, clicking on the "Play" button in the
jog dial will play the new period in the Display Area, change the period start and
end time label, the Pull Bar and Histogram Area will change, too. If the selected
period is not present in the database, the data in the period selector will change
to the previous correct start and end time and a warning message will be
displayed.
Playback Method Selector
Full Range
If you select this method, the database will be displayed from the beginning
to the end of this location. Any change in the period selector will take no
effect unless you change this selector to "Time Period".
Time Period
If you change the playback method to "Time Period", you can modify the
start and end time in the period selector. When you click on the "Play"
button in the jog dial, the period you select will be displayed.
Events Preview
This method will change the display mode from the normal display mode
to the preview mode.
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