Disclosed is a transponder of a radio frequency identification system. Connected to a controller is a memory storing r-pages of k-bits of data. A first page includes an ID code relating to an integrated chip forming part of the transponder. The controller is configured, after the transponder has been interrogated by a reader, automatically and on a transponder talk only basis, to transmit transponder ID data including a concatenation of pages. Each page is led by a respective m-bit header. The header includes: (a) a first part having a random number, (b) a second part having for the first page in the ID data, a total number of pages in the ID data and for any subsequent page, a page number of the page in the memory and; (c) a third part having a sequential number for the page in the ID data.