The purpose of the FLAG ID is to uniquely identify the manufacturer of communicating equipment as specified in the DLMS UA Blue Book and Green Book, and other relevant standards.

FLAG IDs are assigned and maintained by the DLMS User Association.

flag id usages

FLAG IDs are used for electricity, gas, heat and water metering systems in conjunction with one or more of the following standards for meter data exchange; new standards may be added in the future.

  • DLMS/COSEM Blue Book and Green Book
  • IEC 62056 DLMS/COSEM (IEC version of the Blue Book / Green Book)
  • EN 13757 M-Bus
  • EN 1434-3 Heat meters
  • ISO 22158 Water meters

flag id structure

ABC = aBC, AbC, ABc, abC, aBc, Abc, abc.

A FLAG ID consists of three upper case letters taken from the ISO basic Latin alphabet (26 letters).

17 576 FLAG IDs are available. With a growing number of manufacturers and usages, DLMS UA applies strict control over FLAG ID registrations and allocates sparingly FLAG IDs.  

DLMS UA will allocate the FLAG ID and it will include any combination of the three letter sequence registered in upper case and lower case e.g. the registration of ABC implies the registration of aBC, AbC, ABc, abC, aBc, Abc, abc.