This Standard, as a basis for the other parts of IEC 63119, specifies terms and definitions, general description of the system model, classification, information exchange and security mechanisms for roaming between EV Charge Service Providers (CSP), Charging Station Operators (CSOs) and Clearing House platforms through roaming endpoint. It provides an overview and describes the general requirements of EV roaming service system. IEC 63119 series are applicable to high-level communication involved in information exchange / interaction between different CSPs, as well as between a CSP and CSO with or without Clearing House platform through the roaming endpoint. IEC 63119 series do not specify the communication either between Charging Station (CS) and Charging Station Operator (CSO), or between EV and CS.