For several years the DLMS User Association has published meter data exchange standards in the form of coloured books. The colours have a distinct meaning: green for protocol, blue for objects, yellow for conformance and, new this time, white for glossary.

The DLMS UA has started to revise these books and will publish the new editions in the near future. The main driver of this work is the introduction of a new communication profile, based on TCP-UDP/IP, to enable data exchange with metering equipment via the Internet.

Growing experience with actual implementations, conformance testing and field use is also reflected in these new versions, while maintaining compatibility. Because the DLMS User Association liaises with IEC TC13 WG14, and is commissioned as maintenance agent, most of these modifications will enter into International Standards.


The part Data link layer using HDLC protocol requires a minor amendment only, to allow using longer frames for better communication efficiency. An Amendment of IEC 62056-46 will be published by IEC TC13.

A new part, TCP/UDP-IP based COSEM transport layer for IP networks specifies a transport layer based on the Internet TCP and UDP protocols, including the mapping of the ISO style COSEM Application layer services to TCP and UDP function calls. This will be published as IEC 62056-47.

The part COSEM Application layer is enhanced with a new part specifying the use of the application layer supported by the TCP-UDP/IP based COSEM transport layer. The protocol for application association establishment and release has been adapted to the Internet environment. A new integral text will be published as IEC 62056-53 Ed.2.


The part Object Identification System (OBIS) incorporates many new codes covering new functionality, like power quality monitoring and loss measurement, proposed by DLMS UA members. This part will be published as IEC 62056-61 Ed.2

The part COSEM Interface classes contains the new TCP/UDP-IP related interface classes for setting up the communication channels. For better interoperability, the data types for some attributes are now more strictly defined. This part will be published as IEC 62056-62 Ed.2.

The relevant parts of EN 13757-1, covering non-electricity metering equipment, is also incorporated, so that the Blue book will cover all types of energy metering equipment.

The Yellow book, containing the specification of the Conformance Test Tool, is being updated to allow testing of the new features.

The White book is new. It explains DLMS/COSEM terms which are used in all the other books, and is a great help for new and experienced users of DLMS/COSEM. It has recently been published by the IEC as IEC/TR 62051-1 (2004-01).