Naked Science Forum

General Science => General Science => Topic started by: JimBob on 25/07/2007 04:10:19

Title: Credit cards from a distance
Post by: JimBob on 25/07/2007 04:10:19

Up until now, you have had to swipe a credit card through the magnetic reader? How do the new "flash-you-card" readers work?

Title: Credit cards from a distance
Post by: kdlynn on 25/07/2007 04:12:26

i believe it's a little chip. the thing you hold your card up to can read it. somehow. or i'm wrong. it's making less sense the more i write

Title: Credit cards from a distance
Post by: another_someone on 25/07/2007 04:48:30

Not sure what you mean by 'flash you card'?

There are three primary technologies for reading cards (only two that I know are used for credit cards, but the third is used for various travel cards and entry access cards).

The old fashioned magnetic strips that you swipe.

Chips with electrical contacts that you push into the reader, the contacts connect within the reader and interrogate the microchip on the card.

RF induction readers that send out a radio signal that induces a current in the card, that then sends back a low power RF response.

Title: Credit cards from a distance
Post by: paul.fr on 25/07/2007 16:24:28

Quote from: another_someone on 25/07/2007 04:48:30

RF induction readers that send out a radio signal that induces a current in the card, that then sends back a low power RF response.

I think that is what JimBob, is refering to. This system is also used in some pubs, where the patrons have a small device inserted just beneath the skin. Their bartab is stored on the small chip so no money changes hands with each transaction. You simply pay your bill at the end of the night.

Title: Credit cards from a distance
Post by: kdlynn on 25/07/2007 16:32:27

no they are credit cards with a chip in them. all you do is hold the card up to this thing and it reads your credit card info without it being swiped or inserted into anything. my ex used to leave his card in his wallet and his wallet in his pants and hold his behind up to the gas pump and it read his card. lol

Title: Credit cards from a distance
Post by: another_someone on 26/07/2007 03:14:45

Quote from: kdlynn on 25/07/2007 16:32:27

no they are credit cards with a chip in them. all you do is hold the card up to this thing and it reads your credit card info without it being swiped or inserted into anything. my ex used to leave his card in his wallet and his wallet in his pants and hold his behind up to the gas pump and it read his card. lol

It sounds like it is the same RF induction system at work, but it would worry me because there have been known to be reliability problems with such devices (there have been cases where people have been prosecuted for travelling on public transport without paying their fare because they had an oyster travel card, that uses the same system, and they thought they had flashed it at the system, but the system silently failed to read the card).