Part of a series of International Standards that specify a contactless smart card. The card can be carried by members of the public in a purse or wallet and when presented nearby a terminal device give access to places, goods or services. In addition, the card can be attached to objects like bags and valuable items which can then be tracked whilst in the vicinity of a reading device. Defines the power and communications interface between the vicinity card and the reading device. Other parts of ISO/IEC 15693 define the physical dimensions of the card and the commands interpreted by the card and reader.