The PC-D500MA is an AC to 12V DC power converter which allows you to power DC surveillance cameras with an AC power supply source. This is convenient if you already have AC power run or if you need to run the power longer distances. AC power can be run much longer that DC power because DC voltage tends to drop after 100-150 feet.  This AC to DC power converter accepts 15-26VAC or 15-28V DC as the power input and outputs regulated DC12V at 500mA.