ISO/IEC 7816-12:2005 specifies the operating conditions of an integrated circuit card that provides a USB interface. An integrated circuit card with a USB interface is named USB-ICC.
ISO/IEC 7816-12:2005 specifies
- the electrical conditions when a USB-ICC is operated by an interface device - for those contact fields that are not used, when the USB interface is applied;
- the USB standard descriptors and the USB-ICC class specific descriptor;
- the data transfer between host and USB-ICC using bulk transfers or control transfers;
- the control transfers which allow two different protocols named version A and version B;
- the (optional) interrupt transfers to indicate asynchronous events;
- status and error conditions.
ISO/IEC 7816-12:2005 provides two protocols for control transfers. This is to support the protocol T=0 (version A) or to use the transfer on APDU level (version B). ISO/IEC 7816-12:2005 provides the state diagrams for the USB-ICC for each of the transfers (bulk transfers, control transfers version A and version B). Examples of possible sequences which the USB-ICC must be able to handle are given in an informative annex.