AFI (Applikation Family Identifier) for libraries


ISO TC46/SC4/WG11 RFID in libraries




Hosted by Danish Agency for Libraries and Media

Last update: 17 February 2009



AFI definition


The AFI (Application Family Identifier) is a mechanism used in the data protocol and the air interface protocol to select a class of RFID tags relevant to an application, or aspect of an application, and to ignore further communications with other classes of RFID tags with different identifiers

The AFI is a single byte code, often in the systems memory of the tag.



AFI assigned to libraries


On request by EDItEUR, NISO and Danish Standards The Data Constructs Steering Group of ISO/IEC 15961 has allocated RFID Data Constructs including AFI value C2 (hexadecimal) (also written: C2HEX) explicitly for library use.


If the AFI is used for security purposes, the AFI value ”C2” is for items out for loan. For items in stock are used AFI value ”07” more general for ”items in stock”.


See letter from Secretary Data Constructs Steering Group:


EDItEUR has followed up with explanations and instructions:



A library may use the AFI in one of two ways:


·        It may use a single AFI, the value C2HEX assigned under the registration of ISO/IEC 15961-2. This distinguishes library items from all others, and avoids the risk of an RFID reader in another domain reading the RFID tag on a loan item and confusing its encoded content with data in an application outside the library domain. It also enables a library system to reject items that carry a different AFI code, possibly from another domain visited by a client.

·        The AFI may additionally be used as part of an "item security system" where the AFI value C2HEX is written to tags for items that are on loan to a client.  When the books are returned, an in-stock AFI (07 HEX, as agreed by JTC1 SC31 WG4 SG1 to be included in 15961-3) is written to the tag.




ISO/IEC 15961:2004 Information technology -- Radio frequency identification (RFID) for item management -- Data protocol: application interface

Link to ISO/IEC 15961 in ISO Catalogue: