Most cashless payment systems using RFID seem to use HF (13.5MHz) tags. My questions are:
Why do RFID wristbands used for cashless payments use HF over LF transponders? Some access control applications seem to use LF transponders (tags) and I would have thought that the use-case for cashless payments (proximity of access card/wristband to a reader) is similar.
There are a multitude of standards for contactless ICs:
- ISO14443 for proximity contanctless cards [even within this, I believe there are variations.]
- ISO15693 for vicinity contactless cards
- ISO18000 set of standards for RFIDs EPCglobal Class 1 Gen 2 (=18000-6C)
Would I be right in understanding that for cashless payments using RFID wristbands, I should be looking at ISO14443 compliant tags (i.e., HF tags that have a range of ~10cm)?
Some existing cashless payment systems (for example, the one described in this example) seem to require a "double-tap" - once for reading wristband data and the second, for writing back (balance amount). Is a double-tap unavoidable?
EDIT: Some over-zealous moderation has resulted in this question being put on hold. I had done my research and had asked very specific questions, each of which could have been answered by someone knowledgeable in the field, with a sentence or two, so I don't understand the rationale for moderation. Luckily for me, a kind soul answered my questions just in time. Thank you Nils!