ISO 11785

ISO 11784 & 11785 are international standards that regulate the radio frequency identification (RFID) of animals, which is usually accomplished by implanting, introducing or attaching a transponder containing a microchip to an animal.

RF identification of animals requires that the bits transmitted by a transponder are interpretable by a transceiver. Usually the bit stream contains data bits, defining the identification code and a number of bits to ensure correct reception of the data bits. ISO 11784 specifies the structure of the identification code. ISO 11785 specifies how a transponder is activated and how the stored information is transferred to a transceiver (the characteristics of the transmission protocols between transponder and transceiver)

These standards are updated and expanded in ISO 14223 which regulates "advanced" transponders for animals, and ISO 24631 which regulates testing procedures for conformance with ISO 11784 & 11785 as well as performance.

The technical concept of animal identification described is based on the principle of radio-frequency identification (RFID). ISO 11785 is applicable in connection with ISO 11784 which describes the structure and the information content of the codes stored in the transponder.

The International Organization for Standardization (ISO) draws attention to the fact that compliance with clause 6 and Annex A of this International Standard may involve the use of patents concerning methods of transmission.

The carrier frequency for animal identification is: 134.2 kHz. There are 2 ISO approved protocols in use to communicate between tag and reader:

In DBP a 1 is encoded as 00 or 11 and a 0 is encoded as 01 or 10, such that there is at least one transition per bit (so 11 is encoded as 0011 and not as 0000 or 1111)

ISO 11784:1996 Radio-frequency identification of animals - Code structure Published. The first 3 digits of the ID are the manufacturer code.

With half duplex, the tag must store sufficient energy when the receiver's activating field is turned on to allow it to transmit when the activating field is switched off. This makes the receiver simpler, as it is not necessary to pick up the weak signal from the tag among the strong activating field. The disadvantage is that the HDX tag can not transmit when the activating field is turned on.

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