> SIM cards are just smart cards. [...] SIM cards no longer conform is ISO 7810 in most cases (having migrated to the smaller micro and nano formats), but conti

> SIM cards are just smart cards. [...] SIM cards no longer conform is ISO 7810 in most cases (having migrated to the smaller micro and nano formats), but continue to be compliant with ISO 7816 for electrical and protocol compatibility. Over the past 20 years, I've used mobile cellular telephones that take mini-SIM, micro-SIM, and nano-SIM. I didn't get to experience the full-size SIM card, but learned about this obscure fact from online photos and museums. Example: https://twitter.com/phone_museum/status/1287310071907713024 https://twitter.com/phone_museum/status/1287310071907713024 > Why is it that SVCs gained so little traction for payments in the US? Another obscure point is that during the Bitcoin craze of the mid-2010s, the Canadian government tried to pitch MintChip as a competitor. It fizzled out and went nowhere. https://en.wikipedia.org/wiki/MintChip https://en.wikipedia.org/wiki/MintChip > Offline systems simplify payment networks in some ways, but also add complexity, which is often apparent in transit systems that combine offline terminals (for example in buses) and online terminals (for example at train platforms). [...] If you add value to a card with a zero (or near zero) value and then try to board a bus, it is likely that you will be rejected: the value-add hasn't been written to the card yet, and the bus terminal hasn't been told about it. The transit operator often sets an expectation of one business day for online value adds to be available if your first trip is an offline terminal If you add value to a card with a zero (or near zero) value and then try to board a bus, it is likely that you will be rejected: the value-add hasn't been written to the card yet, and the bus terminal hasn't been told about it. This perfectly describes the situation in Toronto/Ontario with PRESTO, adding value, and tapping on buses.