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Can I Read Passive UHF RFID Tags Simultaneously?

Posted By RFID Journal, 12.06.2017

How can I interrogate the EPC, TID and user memory for multiple tags at the same time, without needing to read them one by one in order to access that memory?




You can never read passive UHF RFID tags simultaneously. Tags are read so quickly that it appears the reader is communicating with more than one tag at the same time, but this is not the case. Whether a reader is interrogating just a serial number or a serial number, a TID and user memory, it always communicates with one tag at a time.

The air-interface protocol includes algorithms that enable a reader to quickly filter out all tags within the field except one, and ask for its serial number and other information. It then communicates with the next tag, the one after that and so on, until all tags are read.

—Mark Roberti, Founder and Editor, RFID Journal


Albertus PRETORIUS 2017-12-14 05:44:38 PM
Ahmad, the current reader interface protocols all allow you to read two memory banks at a time; typically UII/EPC + TID. Lately many applications needs object attributes and therefore a need now exist to read UII/EPC + TID + UserMemory. The new reader interface currently under development by the RAIN alliance will allow you to do that (RAINrfid.org). The only ways to do it currently (using LLRP or proprietory vendor commands are: 1. Inventory on UII/EPC only and then reinventory + TID, and then reinventory + UserMem. 2. Inventory + TID, and then reinventory + UserMem. You will note both is highly inefficient, but it works. Also note that tags which has the same UII/EPC programmed will give wrong results. A bigger concern is the encoding decoding of data to allow you to identify your own tags. ISO/IEC 20248 is a new data standard which allows you to identify your own tags, program your own data structures and optionally include a digital signature verification code. I am the editor of this standard. If you want to know more please contact me at bertus.home@gmail.com

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