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 the relevant standards.
FLAG IDs are assigned by the DLMS User Association in cooperation with the FLAG User Association.
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.
A FLAG ID consists of three upper case letters taken from the ISO basic Latin alphabet (26 letters).
With this, 17 576 FLAG IDs are available. Currently (July 2018) 1 303 FLAG IDs are registered. With growing number of manufacturers and usages, FLAG IDs are allocated sparingly: the DLMS UA – in partnership with the FLAG Association – applies strict control over FLAG ID registrations.
The manufacturer may use 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.