Thailand's AIS' "mPay" e-wallet

ais.co.th

I'm interested in knowing how these guys implemented this "solution". But after reading the entire website, I still don't know how it works. Obviously this is gibberish written by a PR team that doesn't really know how the system works!

So, let's say I walk in to a store, choose what I want to buy, and once at the cash register, I say I want to pay with mPay...

... and then what happens?

Do I have to go to a terminal that looks like an ATM and type something? Do I have to send an SMS to the AIS headquarters? Do I have to swipe my mobile somewhere?

I only know that at the end I get a confirmation SMS, and that's why they tie this thing to the pocession of one mobile. But how does the payment process get started?

I bet that not even the guys who wrote the website know.