debit cards

[empo]

how are debit cards linked to accounts by banks?

[chazza]

The card will have the sort code and the account number on it

[Whickerman]

vvvvvvvvvvvveeeeeeeeeeeeeeeeeeerrrrrrrrrrrrrrryyyyyyyyyyy slowly.

[moleymoley15]

magnetic strip

[mattfox]

Magic!

[rojash]

An exceedingly teeny tiny length of wire

[rojash]

To expand a little: If you carefully examine the edge of your debit card where the magnetic strip joind the card, you will find a teeny weeny tine hole. When the card is inserted into a card reader (in a shop or ATM), an electrical impulse from the machine causes the card to extrude a minutely thin but extraordinarily long piece of wire, which goes down a TOP SECRET teeny tiny tube that only banks know about and snakes all the way to your bank. At the bank, an employee with an exceeding powerful microscope read the account details from the end of the wire where they were embroidered by poor people living in the 3rd world. He then checks you account, and if all is OK, he ties a little note to the end of the wire, and gives it a tug, which turns on the magnetic strip causing the wire to be retracted back into the card, quick as a flash. As it shoots back into the card, the note tied to the end is too large and falls off onto the counter as a receipt.

[rojash]

ps
Not all debit cards work in this way

[bluejonjo]

Elves.

[snook]

Rojash, loved that explanation! You should set up a How-It-Works website explaining all those technological marvels that confound us on a daily basis. We need to know how they work! And it has to be amusing, not boring like all the techie explanations that you read that make you want to set your hair on fire and beat it out with a spade.

When you set your site up, let us know the name so we can log on. Oh, and explain how that logging on thing works...

[rojash]

Snook, I was going to set up a web site just as you describe, but it transpires that for such a site you need double-knit wool, and I have only 2-ply rayon, and No. 3 knitting needles.