I have a 12 volt 25 amp Power supply, supplying everything. The Black Box converts the 12 VDC to 9 and 6 VDC for the handhelds, bubble pack charger and Remote control interface. It allows me to get rid of all the wall transformers. I think I will eventually get rid of the power supply supply and use a 12 volt battery with some sort of trickle charger to have it work like a UPS system.