The Sleep Mode feature provides protection to the LCD screen by putting the screen to sleep when the phone is not in used.
The sleep mode activates after a certain period of inactivity, this timeout period has 2 settings:
The Office hours are configurable from Monday to Sunday with accepted values from 00 - 23 (default 07 - 21).
From the phone's web interface, navigate to Setting -> Sleep Mode page.
From the physical phone, access the phone menu and navigate to the Sleep Mode page.