This document defines the data transfer models between roadside equipment (RSE) and integrated circuit card (ICC) and the interface descriptions between the RSE and on-board equipment (OBE) for on-board accounts using the ICC. It also provides examples of interface definitions and transactions deployed in several countries. This document covers: data transfer models between the RSE and ICC which correspond to the categorized operational requirements and the data transfer mechanism for each model; interface definition between the RSE and OBE based on each data transfer model; interface definition for each model; functional configuration; RSE command definitions for ICC access; data format and data element definitions of RSE commands; a transaction example for each model in AnnexB. Figure3 shows the configuration of an on-board account and the scope of this document. The descriptions in this document focus on the interface between the RSE and OBU to access the ICC. Figure3 Configuration of an on-board account and the scope of this document Figure4 shows the layer structure of the RSE, OBU and ICC where the mid-layer of application interfaces are denoted as the practical scope of this document. NOTE The existing standards for physical and other protocol layers both between the RSE and OBE, and between OBE and ICC, are outside the scope of this document. For example, DSRC-related items (L-1, L-2 and L-7) and ICC-related items (ICC commands, data definition, etc.) are outside the scope of this document. There are two types of virtual bridges contained in an OBU. The first type is Bridge-1 on which an RSE command sent from the RSE is decomposed and the ICC access command contained in the application protocol data unit (APDU) part of the RSE command is transferred to ICC I/F to access the ICC. The second type is Bridge-2 in which an RSE command sent from the RSU is transformed to ICC access command and transferred to ICC I/F to access the ICC. Bridge-1 corresponds to the transparent type and the buffering type defined in this document, whereas Bridge-2 corresponds to the cashing type. Figure4 Application interfaces of RSE, OBU and ISS and the scope of this document