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
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