This part of IEC 62056 specifies the overall structure of the OBject Identification System (OBIS) and the mapping of all commonly used data items in metering equipment to their identification codes. OBIS provides a unique identifier for all data within the metering equipment, including not only measurement values, but also abstract values used for configuration or obtaining information about the behaviour of the metering equipment. The ID codes defined in this standard are used for the identification of: • logical names of the various instances of the ICs, or objects, as defined in IEC 62056-6-2; • data transmitted through communication lines; • data displayed on the metering equipment, see Clause A.2.