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HF Transponder Memory Structure

Information about the memory structure of a HF transponder
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To utilize a HF transponder, it is necessary to understand its memory structure. The structure is defined by the ISO/IEC 15693 standard, so compatible readers conforming to the same standard would be able to access the memory content.

HF Memory Structure

The following picture shows a schematic structure of a HF transponder according to ISO/IEC 15693.

Explanation of the different memory areas

UID (Unique Identifier):

The UID is a unique ID of 8 Byte. It is set permanently by the IC Manufacturer and therefore can not be edited. According to ISO/IEC 15693 the UID starts with the header byte of "E0" (Most Significant Bit - MSB). The second Byte contains the IC manufacturer code. The remaining 6 Bytes represent the unique serial number of the transponder assigned by the IC manufacturer.


AFI (Application Family Identifier):

The use of AFI is optional.

According to ISO/IEC 15693 the AFI is used to assign the transponder to a specific application family. With the RFH6xx devices it is possible to filter the read transponders by using the AFI filter. This helps for example to read only the transponder on a box instead of reading products inside the box as well (provided that the AFI of the transponder on the box is different from the AFI of the transponders on the  products in the box)

DSFID (Data Storage Format Identifier):

The use of DSFID is optional.

The DSFID indicates how the stored data is structed in the transponder. See ISO/IEC 15693 for further information.



The blocks are used to store customer data on a transponder. Depending on the used IC, the transponder can have a block size of 4, 8 or 32 bytes. The number of provided blocks depends as well on the used transponder IC. It is not possible to use ICs with 32 byte blocks with RFH5xx.


Lock Function:

It is possible to lock the AFI, DSFID and the blocks of the transponder to prevent any changes of the stored data. If a block is locked it is not possible to overwrite this block again. The status of the data (locked / not locked) can be read out as well. 

Please be aware that only RFH6xx devices are supporting the lock function via command.

Reference to SOPAS ET


The transponder data can be accessed via the "Transponder Access" page in SOPAS ET or via commands. The following picture shows an example of an accessed transponder in SOPAS ET with a RFH6xx device.


The next picture shows an example of the Reading Statistics of a RFH5xx device with the memory banks marked as well. 

The content of the blocks has to be read out manually via the IO-Link Process Data page shown below.

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