ISO 15693
The standard ISO / IEC 15693 specifies physical, physical and information engineering features of contactless RFID - transponders and readers for the wireless transmission of information securely over short distances.
The standard is divided into 3 parts:
- Part 1: physical dimensions of corresponding transponder cards
- Part 2: physical parameters and methods for bit transmission (e.g. modulation, 13.56 MHz frequency)
- Part 3: Structure of the data packets and commands for queries from the reader to the transponder and for the responses. Here, however, all commands except for two (anti-collision and sleep) are optional, with which both transponders can be implemented that provide a memory and simple transponders that only contain one ID.
The chip series M24LR from STMicroelectronics is not completely standard-compliant due to a non-standard block addressing. The transmission range of this standard is slightly higher than that of the ISO 14443 standard, which works with the same frequency, when the appropriate reading devices are used .
The standard is supported as NfcV in all NFC- enabled Android smartphones. Since autumn 2015, the standard has also been officially recognized by the NFC Forum as a possible basis for NFC-coded information.
Applications
In the standard itself, various values are given for the so-called AFI (Application Family Identifier) field. With this, a reader can check whether the tag read is suitable for the desired purpose.
A very popular application is the registration of loan books and media.
Technical details
An ISO 15693 tag replies to the initialization with its UID (Unique ID). This is eight bytes long and always begins with a byte 0xE0. This is followed by a byte with a manufacturer code that stands for the manufacturer of the tag. This is derived from ISO 7816 . The remaining 6 bytes form a unique serial number.
The standard defines a series of commands on the application layer, but only the command for a collision detection mechanism, if several tags are in the reading field of a reader, and the command to send the tag to sleep are mandatory. All other commands are optional. There is also an area for manufacturer-specific commands. The optional nature of the commands makes it possible, on the one hand, to build tags that function as a data memory, as well as simple tags without data memory for which only the UID is relevant, as this can be registered in the system connected to the reader and can trigger an action there (e.g. unambiguous indication of a book in the lending library). On the other hand, this flexibility makes it more difficult to create an ISO 15693 reading application that works universally with all tags and maps their complete range of functions.
To further support this concept, there are the AFI (Application Family Identifier) fields, which can be used to code which application the tag is intended for (e.g. library, ski pass ...) and the DSFID (Data Storage Flag IDentifier) field. With this, the layout of the data stored on the tag can be determined in a customer-specific application.
All commands and their responses are protected by a CRC checksum. Error codes for errors in command execution are also predefined.