Abstract: A peer-to-peer approach is used for the transfer of electrical power between devices (10,30). A communications link (24) is used for negotiation of the details of a desired power-supply transaction between a power-supplying device and a power-receiving device, including the electrical specification of the power to be transferred. When the transaction details are settled, a power supply link (23) is used for implementing the agreed transfer of power. The negotiated electrical specification can include one or more of: the voltage, the waveform (ac or dc), the ac frequency, the power factor, the maximum current, and the total power for the proposed transfer.