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That seems like a question for @lxgr :-) As far as I can tell, the NFC ecosystem is a mess of competing, incompatible protocols from different companies, as we
by kens 2y ago
That seems like a question for @lxgr :-)
As far as I can tell, the NFC ecosystem is a mess of competing, incompatible protocols from different companies, as well as incompatibilities for historical reasons.
For example, Clipper uses MIFARE DESFire, which is the more secure sibling of the Ultralight chip that I examined. Washington's SmarTrip cards use MIFARE Plux X. New York City's OMNY, on the other hand, is apparently built on top of the Mastercard payment network using EMV. Montreal's rechargeable OPUS card (not the disposable one I examined) uses the completely different Calypso standard. FeliCa was developed in Japan along a different path and has a different standard (NFC-F vs NFC-A) with different modulation, protocol, and data rates. The NFC chips used in phones try to be compatible with as much as possible. These NFC systems all use the same 13.56 MHz frequency, so the radio hardware is compatible across them.
- Tijdreiziger 2y agoHow and why did you learn about this topic? :)
- lxgr 2y agoOn it, but I couldn't have said it better :) To expand on Felica vs. ISO a bit: Theoretically Felica is a different stack from ISO 14443, but it's close enough that it almost got specified as a variant of ISO 14443 as well (C; MIFARE and most other systems use A). NFC does specify Felica as one possible official tag type (then called NFC-F, as opposed to NFC-A and NFC-B), so practically, most mobile devices can just also read it. For anybody wanting to experiment a bit, I can highly recommend getting any Android device and installing NFC tag reader by NXP; it'll show you what technology exactly a given card uses, and in some cases can show you other interesting information as well. There's also an app that lets you read the current balance of various transit cards.