W. K. Lis
Superstar
No need....it gets tested every day at Union station in the evening rush....people just tap one after another....person "A" taps...their transaction has not even cleared the screen and person "B" taps and is charged..then "C"...then so on and so on.
The readers are ready for the next card as soon as it beeps the last one.
The difference between presto readers and retail outlets is quite large. Presto readers are passive but active...that is they are not presenting a transaction but are always "awake" awaiting for a card to pay for one.......retail outlets, however, their readers are asleep awaiting the cash register to send them a pending transaction then they become active until they get a tap from a card that completes that transaction.....after that you can club the machine as much as you like with your card...it won't take any money from you until the retailer sends it another pending transaction.
It is not even clear to me how Presto readers will work with visa/mc/debit cards on a GO system or any other fair by distance system. Right now it is pretty simple to tap on at a TTC subway station with the new readers cause they charge the same fare all the time....so the reader just needs to know "presto card discount the fare.....visa card charge the full cash fare"
The U.S. is behind Canada in using the RFID chip on their credit and debit cards.