The 62056 OPC Server implements IEC 62056-21 (EN 62056-21, formerly IEC 61107) protocol. This protocol is designed for electricity metering (data exchange for meter reading, tariff and load control). Note that this protocol is part of larger protocol family, and is also known under different names, so if you are unsure whether this product is for your protocol, please contact us for clarification. Names like DLMS and FLAG are all related to IEC62056 (EN62056), but are not the same.