A system for supplying uninterruptible power, comprising: a housing; a power supply input disposed within said housing, said power supply input having a power supply interface on an outside of said housing; a power over Ethernet source equipment input disposed within said housing, said power over Ethernet source equipment input having a power over Ethernet source equipment interface on an outside of said housing; a powered device output disposed within said housing, said powered device output having a powered device interface on an outside of said housing; an alternative power supply disposed within said housing; a powered device connected to said powered device output by an Ethernet cable; power over Ethernet source equipment connected to said power over Ethernet source equipment input, said power over Ethernet source equipment being powered separate from said power supply input and said alternative power supply; and characterized in that a control module is connected to said power supply input, said power over Ethernet source equipment input, said powered device output, and said alternative power supply, said control module being comprised of an injector means, a comparator means, and a switch means, said injector means connecting said power over Ethernet source equipment input, said power supply input, and said alternative power supply to said powered device output, said comparator means detecting power from said power supply input and to said powered device output, said switch means connecting said power supply input and said alternative power supply to said injector means, said injector means is comprised of a load circuit, said load circuit storing power from at least one of said power supply input, said power over Ethernet source equipment input and said alternative power supply, said load circuit distributing power to said powered device output, said comparator means monitors voltage of said load circuit, said control module has a first mode of operation for supplying power to said powered device from said power supply input, a second mode of operation for supplying power to said powered device from said alternative power supply, a third mode of operation for supplying power to said powered device from said power over Ethernet source equipment input, a fourth mode of operation for supplying power to said alternative power supply from said power supply input, a fifth mode of operation for supplying power to said alternative power supply from said power over Ethernet source equipment input, the first mode and the fourth mode are not concurrent with the second mode, and said switch means manages the modes of operation of said control module. a housing; a power supply input disposed within said housing, said power supply input having a power supply interface on an outside of said housing; a power over Ethernet source equipment input disposed within said housing, said power over Ethernet source equipment input having a power over Ethernet source equipment interface on an outside of said housing; a powered device output disposed within said housing, said powered device output having a powered device interface on an outside of said housing; an alternative power supply disposed within said housing; a powered device connected to said powered device output by an Ethernet cable; power over Ethernet source equipment connected to said power over Ethernet source equipment input, said power over Ethernet source equipment being powered separate from said power supply input and said alternative power supply; and characterized in that a control module is connected to said power supply input, said power over Ethernet source equipment input, said powered device output, and said alternative power supply, said control module being comprised of an injector means, a comparator means, and a switch means, said injector means connecting said power over Ethernet source equipment input, said power supply input, and said alternative power supply to said powered device output, said comparator means detecting power from said power supply input and to said powered device output, said switch means connecting said power supply input and said alternative power supply to said injector means, said injector means is comprised of a load circuit, said load circuit storing power from at least one of said power supply input, said power over Ethernet source equipment input and said alternative power supply, said load circuit distributing power to said powered device output, said comparator means monitors voltage of said load circuit, said control module has a first mode of operation for supplying power to said powered device from said power supply input, a second mode of operation for supplying power to said powered device from said alternative power supply, a third mode of operation for supplying power to said powered device from said power over Ethernet source equipment input, a fourth mode of operation for supplying power to said alternative power supply from said power supply input, a fifth mode of operation for supplying power to said alternative power supply from said power over Ethernet source equipment input, the first mode and the fourth mode are not concurrent with the second mode, and said switch means manages the modes of operation of said control module.