The ISO standard for radiofrequency identification of animals

Abstract Radiofrequency identification (RFID) is a good way to identify animals. To overcome the problem that systems were not interchangeable, a Working Group of the International Organisation for Standardization (ISO/TC23/SC19/WG3) has defined a standard on the code structure in the transponder and on the technology for the communication between reader and transponder. In the code structure standard ISO 11784, the 64 bits of code are split into three parts: 16 bits for special purposes, of which two have already been assigned and 14 have been reserved for future needs; 10 bits containing a reference to the issuing country or the manufacturer who programmed the transponder; and 38 bits of code containing a serial number. The combination of country/manufacturer’s code and serial number (bits 17–64) form a worldwide unique identification number of the animal. This number can be used to retrieve information on an individual animal. A prerequisite is the existence of a logistical system starting with a database on country or manufacturer level, which redirects queries for information to the right database on a lower level, where the actual information can be found. For some countries such a system may not be attainable in the near future. The principle of the standard on the technical concept ISO 11785 is that two different types of RFID systems (full-duplex, FDX, and half-duplex, HDX) are combined. An FDX transponder sends its telegram during activation by the reader; in the HDX system it responds during a pause after it was charged with energy during activation. A dual adaptive timing protocol was necessary to make the system fast enough. It was verified that the standardised technology could fulfil all the requirements. A method has been described to enhance ISO readers to make them able to read old transponders, already implanted in animals, that are not compatible with the standard.