Samsung SyncMaster MD230 User Manual page 13

POWER S/W : Turns the product on and off.
•When the product is connected to a PC, you can turn the product on and use it.
•When both the DVI (<Digital>) and D-Sub (<Analog>) cables are connected, you can select the input signal <Digital / Analog> by
pressing the [ SOURCE] button on the multi control pad.
Installing the Product 2-2