D-Link DES-2212 - Manual (Page 27)

Installation 15
Connecting Power
The switch features a power supply unit that automatically adjusts to the level
of the input voltage. Supported voltage levels range from 100V to 240V at
50 or 60 Hz. Your local voltage level should fall within this range.
To turn on the DES-2212, plug in the provided AC power cord into the
power connector at the rear of the system, then flip the rocker power switch
to the “1” position. After turning on the power, the Power indicator on the
front panel should light.
It is not necessary to turn off the DES-2212’s power when connecting or
disconnecting network cables (except for the MII port) or console port
connections.