Embodiments relating to a memory tag having a resonant circuit part and a non-volatile memory is presented. The resonant circuit part can be made operable, in response to a reader signal received from a reader, to provide power to the memory, the tag being operable to read the memory and transmit data stored in the memory in response to the signal from the reader. The data is stored in the memory in a plurality of data units, with each data unit having an associated sequence number. The tag is operable to store the sequence number of the data unit to be transmitted in a register in the non-volatile memory. When power is supplied to the memory, the data units are transmitted in sequence, where the first data unit to be transmitted depends on the stored sequence number.