A power delivery connection between a power adapter and a power using device greater than 10 W and up to, but less than 240 W, is defined in this standard. A communications link between the power adapter and the mobile power-using device is also defined. The communications may be used to coordinate the power delivery and provide identification between the power adapter and the power-using device. While intended for portable computing and entertainment devices, power adapters conforming to this standard may also be used with otherre devices (including simple devices, with no communications capabilities, up to 20 W).