IEC 62056-6-1:2015 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. This second edition cancels and replaces the first edition of IEC 62056-6-1, published in 2013. It constitutes a technical revision. The main technical changes with respect to the previous edition are listed in Annex B (informative).