Posted on r/Philippines: How did the MRT's old stored value tickets work?
Haven't ridden the MRT regularly for a long while, I assume these were phased out since may Beep card na.
Specifically, where did they store value? I remember parang thin magnetic (?) card lang sya na parang wala namang chip. And if writeable sya, wouldn't that be insecure, i.e. people might figure out how to change the value of the card.
If there's some kind of centralized database, wouldn't that introduce some kind of network delay for example when the ticket is processed as you leave the station? Mabilis lang maprocess yung ticket e (otherwise, it's a problem during rush hour)
Lol sorry if it's a weird question, baka sakali lang may nakakaalam dito; I remember thinking about this when they were first introduced and I never did get an answer.