An uninterruptible power supply for home/office networking and communication system (UPS) comprising: (i) an AC-DC converter, (ii) a battery charger, (iii) a rechargeable battery array, (iv) a control circuit, and (v) a plurality of DC-DC voltage converters/voltage controllers, wherein, in operation, when an AC power supply is available, the UPS provides a plurality of DC voltage outputs to a plurality of loads Li, through the AC-DC converter, the control circuit, and the plurality of the DC-DC voltage converters/voltage controllers, and provides continuous DC charge to the rechargeable battery array, and when the AC power supply becomes unavailable, the control circuit detects the unavailability of the AC power supply, the UPS provides a plurality of DC voltage outputs to the plurality of loads Li, through an DC supply voltage of the rechargeable battery array, the control circuit, and the plurality of the DC-DC voltage converters/voltage controllers.