A point-of-sale (POS) terminal or station may receive payment information associated with a purchase and seek authorization for payment from a back-end financial system, for example a credit card authorization service. The point-of-sale terminal may receive the financial information from a contactless card. A contactless card communicates with a point-of-sale terminal or other device at least in part without physically contacting the point-of-sale terminal, for example through radio frequency communication conducted in the proximity of the point-of-sale terminal. Some contactless cards may have an on-board battery that provides power to the contactless card's electronic components and communication interface, for example to an antenna. Other contactless cards have no on-board power source but capture energy from a power source co-located with the point-of-sale terminal, for example from an electromagnetic field, and use the captured energy to power the on-board electronics and communication interface.