A data tag containing self-descriptive data, a method for reading such a data tag and a system for interpreting such a data tag are disclosed. Characterizing information about a first data element stored in a memory of the data tag is stored in a first header preceding a first data element. In addition, characterizing information about a second data element stored in the memory of the data tag is stored in a second header preceding a second data element. The application of a multitude of descriptive headers, each characterizing a data element stored in the data tag memory, facilitates flexible data storage on such devices. Furthermore, it also facilitates data compression due to the fact that field lengths can be characterized as well, thus excluding the presence of redundant bits in the data stored in the memory.