ISO 11784 & 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.


RF protocol

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

Protocol Full Duplex (FDX or FDX-B) Half Duplex (HDX)
Modulation ASK FSK
Frequency 129-133.2 kHz 124.2 kHz=1
135.2-139.4 kHz 134.2 kHz=0
Channel code Differential Biphase (DBP) none
Symbol time 0.23845 ms 0.1288 ms 1
0.1192 ms 0
Telegram (bit) 128 112

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)

Code structure

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.

Telegram layout:

  • 8 Startbits 01111110,
  • 1 Animal-No animal indicator,
  • 14 'Reserved for future use'bits,
  • 1 Extra data indicator bit,
  • 10 Country code according to ISO 3166,
  • 38 ID bits,
  • 16 CCITT CRC over the previous 64 bits,
  • 24 Application bits,


With full duplex, the tag can transmit immediately when in the presence of the receiver's activating field. The advantage is that the FDX tag can then transmit continuously and can therefore be read more quickly and more often.

Telegram layout:

  • 11 Startbits 00000000001,
  • 38 ID bits
  • 10 Country code according to ISO 3166,
  • 1 Extra application bits,
  • 14 Reserved bits,
  • 1 Animal bit,
  • 16 CCITT CRC over the previous bits
  • 24 Application bits

In FDX (at least), after the 11 startbits, a framing bit ('1') is sent after every 8 data bits.


Compliance with the standards may require use of techniques which are covered by (or claimed to be covered by) certain patents. ISO takes no position concerning the evidence, validity and scope of these patent rights.

Some patent holder has assured ISO that they will not exert their patent rights concerning FDX B technology. Other patent holders have assured ISO that they are willing to negotiate licenses under reasonable and non-discriminatory terms and conditions with applicants through the world. In this respect, the statement of the holders of these patent rights are registered with ISO.

Attention is moreover drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent rights. In that connection, additional correspondences were received from two other companies not willing to forward pertinent declaration in accordance with the current ISO Directives.


External links

Ear tag

An ear tag is a plastic or metal object used for identification of domestic livestock and other animals. If the ear tag uses Radio Frequency Identification Device (RFID) technology it is referred to as an electronic ear tag. Electronic ear tags conform to international standards ISO 11784 and ISO 11785 working at 134.2 kHz, as well as ISO/IEC 18000-6C operating in the UHF spectrum. There are other non-standard systems such as Destron working at 125 kHz. Although there are many shapes of ear tags, the main types in current use are as follows:

Flag-shaped ear tag: two discs joined through the ear, one or both bearing a wide, flat plastic surface on which identification details are written or printed in large, easily legible script.

Button-shaped ear tag: two discs joined through the ear.

Plastic clip ear tag: a moulded plastic strip, folded over the edge of the ear and joined through it.

Metal ear tag: an aluminium, steel or brass rectangle with sharp points, clipped over the edge of the ear, with the identification stamped into it.

Electronic Identification Tags, include the EID number and sometimes a management number on the button that appears on the back of the ear. These can at times be combined as a matched set, which includes Visual tags with Electronic Identification Tags.Each of these except the metal type may carry a RFID chip, which normally carries an electronic version of the same identification number.

ISO 14223

ISO 14223 Radiofrequency identification of animals — Advanced transponders is an international standard that specifies the structure of the radio frequency (RF) code for advanced transponders for animals. The technical concept of advanced transponders for animal identification described is based upon the principle of radio frequency identification (RFID) and is an extension of the standards ISO 11784 and ISO 11785. This part of the standard describes the air interface between transceiver and advanced transponder.

Apart from the transmission of the (unique) identification code of animals, application of advanced technologies facilitates the storage and retrieval of additional information (integrated database), the implementation of authentication methods and reading of the data of integrated sensors, etc. This standard consists of three parts as described in the foreword:

Part 1: Air interface

Part 2: Code and command structure

Part 3: ApplicationsThis standard has been published. On December 14, 2007, the standard entered stage 90.92 ("International Standard to be revised") in accordance with the ISO international harmonized stage codes.

Microchip implant (animal)

A microchip implant is an identifying integrated circuit placed under the skin of an animal. The chip, about the size of a large grain of rice, uses passive RFID (Radio Frequency Identification) technology, and is also known as a PIT (Passive Integrated Transponder) tag.

Externally attached microchips such as RFID ear tags are commonly used to identify farm and ranch animals, with the exception of horses. Some external microchips can be read with the same scanner used with implanted chips.

Pet recovery service

A pet recovery service is a service that has been created for the specific purpose of reuniting lost or stolen pets with their owners.

Radio-frequency identification

Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically stored information. Passive tags collect energy from a nearby RFID reader's interrogating radio waves. Active tags have a local power source (such as a battery) and may operate hundreds of meters from the RFID reader. Unlike a barcode, the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method of automatic identification and data capture (AIDC).RFID tags are used in many industries. For example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID-tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets enables positive identification of animals.

Since RFID tags can be attached to cash, clothing, and possessions, or implanted in animals and people, the possibility of reading personally-linked information without consent has raised serious privacy concerns. These concerns resulted in standard specifications development addressing privacy and security issues. ISO/IEC 18000 and ISO/IEC 29167 use on-chip cryptography methods for untraceability, tag and reader authentication, and over-the-air privacy. ISO/IEC 20248 specifies a digital signature data structure for RFID and barcodes providing data, source and read method authenticity. This work is done within ISO/IEC JTC 1/SC 31 Automatic identification and data capture techniques. Tags can also be used in shops to expedite checkout, and to prevent theft by customers and employees.

In 2014, the world RFID market was worth US$8.89 billion, up from US$7.77 billion in 2013 and US$6.96 billion in 2012. This figure includes tags, readers, and software/services for RFID cards, labels, fobs, and all other form factors. The market value is expected to rise to US$18.68 billion by 2026.

ISO standards by standard number

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