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International standardization

International standardization is a key element of the strategy of the DLMS User Association

The DLMS UA works closely with international and regional standardization organizations to bring the results of its technical work, the contents of the Blue Book and the Green Book to the public domain.

The standardization work follows the work of the DLMS UA with certain delays. Therefore, the latest version of the specification can always be found in the DLMS UA Books.

IEC, International Electrotechnical Commission, www.iec.ch

IEC Technical Committee TC13 has a working group, WG14 that is responsible for data exchange for meter reading, tariff and load control.

The DLMS/COSEM specification has been adopted by the IEC as part of the IEC 62056 DLMS/COSEM suite since 2002.

New editions of the DLMS UA Books specifying major new elements lead to new editions of the IEC 62056 standards.

The core standards are:

  • IEC 62056-5-3, DLMS/COSEM application layer. Edition 3.0 (2017) is in line with Green Book Edition 8.3;
  • IEC 62056-6-2, COSEM interface classes. Edition 3.0, (2017) is in line with Blue Book Edition 12.2;
  • IEC 62056-6-1, OBIS Object identification system Edition 3.0, (2017) is in line with Blue Book Edition 12.2.


The DLMS UA is D-Type liaison partner of IEC TC13 WG14 and acts as the registration authority for the elements of the standard.

For a full list of the standards in the IEC 62056 suite, please visit the IEC TC 13 website.

CEN, European Committee for Standardization www.cen.eu

CEN, Technical Committee TC294,  Communication systems for meters is responsible for standardization of communication interfaces of smart metering systems for all kind of fluids and energies.

The DLMS/COSEM specification is referenced in EN 13757-1, Communication systems for meters - Part 1: Data exchange, which also includes the OBIS codes for fluids and energies other than electricity.

The DLMS UA is a liaison partner of CEN TC294.

CENELEC, European Committee for Electrotechnical Standardization, www.cenelec.eu

In CENELEC TC13, WG02 Data models and protocols for additional functionality of and data exchange in interoperable multi-utility smart metering systems worked under the Smart Metering Standardization Mandate M/441 of the European Commission to develop standards for smart metering.

This work resulted in Technical Specifications specifying DLMS/COSEM based communication profiles like PRIME PLC and G3-PLC.

The DLMS UA is a liaison partner of CENELEC TC13.

The results of the work of CENELEC TC13 WG02 have been transferred to TC13 WG14 for international standardization.