ISO 11784 / 11785 (Animal ID)

ISO 11784 and ISO 11785 are companion standards developed by the International Organization for Standardization (ISO) specifically for radio frequency identification of animals. These standards work together, with ISO 11784 defining the code structure stored in animal microchips and ISO 11785 specifying the technical characteristics of how the transponders and readers communicate. The system operates at 134.2 kHz, placing it firmly in the low-frequency RFID spectrum, which offers excellent performance through tissue and water content in living animals. The physical layer uses full-duplex communication where the reader generates a continuous electromagnetic field that powers passive transponders implanted under an animal's skin. The transponder modulates this field to send back its identification code by adjusting the load on the reader's antenna. ISO 11785 defines two encoding schemes: FDX-B (Full Duplex) where the transponder transmits continuously, and HDX (Half Duplex) where transmission alternates with charging periods. FDX-B has become the dominant format worldwide due to faster read times and better reliability. Anticollision capability is limited in these standards because the primary use case involves reading one animal at a time during veterinary procedures, border crossings, or livestock sorting. The system is designed for individual animal scanning rather than reading multiple tags simultaneously. Typical read ranges extend from 10 to 30 centimeters depending on transponder size, reader antenna configuration, and whether the tag is a glass tube injectable or larger ear tag format. This short range is actually advantageous in animal applications, ensuring you're identifying the specific animal you're examining rather than nearby livestock. Sample applications include livestock traceability programs for food safety, companion animal identification for pet recovery, wildlife research tracking, equine identification for breeding registries and competition, and zoo animal management. Many countries mandate ISO compliant microchips for pet imports and exports. The standards are maintained by ISO technical committee TC23 for agricultural machinery and equipment. Since their adoption in the 1990s, these standards have enabled global interoperability in animal identification systems, allowing a microchipped pet to be scanned and identified anywhere in the world using compatible readers.