A power adapter, in a presently preferred embodiment, includes a power converter and multiple data ports, and is configured for ease of coupling the power converter into pre-existing premises power connectors. Thus, premises power can be supplied from the power converter and a first data port, via data cabling, to a network terminating device for an external network. Multi-protocol adapters, such as an HPNA (Home Phoneline Network Alliance protocol compliant)/Ethernet adapter, may also be included to provide extension of a protocol (such as Ethernet) over pre-existing premises wiring. A back-up battery is optionally provided, as well as appropriate switches and indicators. Specialized male-female connectors may also be used.