Sushi and RFID

So I was eating Sushi today — the kind that rotates on a belt.
I have already known that these Sushi belt systems have way to track expiration, so that those Sushi plates won’t be circling around on the belt forever making the health department unhappy.


So I ate a few plates of Sushi, and then turned it over to see what’s underneath. It seems like something built inside it.


So I was curious if it is any proprietary RFID system, or perhaps Felica?


It turns out it is using NXP chip SL2ICS20.



Digging it deeper, it doesn’t look like the chip contains so much of information, however there were slight deviation between each plates.



While the display shows each datablock being unlocked, RFID chip itself was still locked (perhaps not permanently locked) so it could be that the system still keeps track of how many times plates has passed through the checkpoint, among other information.