Question about unreadable credit cards

BTox · 12th August 2003, 07:04 PM

One for the physicists,electrical engineers and/or computer scientists - on occasion when I swipe my credit card at the supermarket, it comes up "unreadable". The kid at the register hands me a plastic bag, I put the card in the bag and swipe again, and it works. What's going on? Something to do with static electricity is my only guess, but I would think the plastic bag would exacerbate the problem.

Goshawk · 12th August 2003, 08:04 PM

http://money.howstuffworks.com/credit-card3.htm

Quote:

If the ATM isn't accepting your card, your problem is probably either:

A dirty or scratched magstripe

An erased magstripe (The most common causes for erased magstripes are exposure to magnets, like the small ones used to hold notes and pictures on the refrigerator, and exposure to a store's electronic article surveillance (EAS) tag demagnetizer.)

The problem with your card is probably "dirt", which the baggie covers up.

arcticpenguin · 13th August 2003, 06:29 AM

I have never heard of this, but could come up with possibilities.

Perhaps the reading of the card is marginal, for whatever reason, and swiping it several times would result in a good read regardless of the presence of the bag (i.e. the bag use is superstitious)

Perhaps the thickness of the bag improves the spacing between the magnetic strip on your card and the read head.

12th August 2003, 07:04 PM	#1
BTox Graduate Poster Join Date: Jul 2003 Posts: 1,588	Question about unreadable credit cards One for the physicists,electrical engineers and/or computer scientists - on occasion when I swipe my credit card at the supermarket, it comes up "unreadable". The kid at the register hands me a plastic bag, I put the card in the bag and swipe again, and it works. What's going on? Something to do with static electricity is my only guess, but I would think the plastic bag would exacerbate the problem.
BTox Graduate Poster Join Date: Jul 2003 Posts: 1,588

13th August 2003, 06:29 AM	#3
arcticpenguin woo ban clan Join Date: Sep 2002 Posts: 5,717	I have never heard of this, but could come up with possibilities. Perhaps the reading of the card is marginal, for whatever reason, and swiping it several times would result in a good read regardless of the presence of the bag (i.e. the bag use is superstitious) Perhaps the thickness of the bag improves the spacing between the magnetic strip on your card and the read head.
	__________________ The power of accurate observation is frequently called cynicism by those who don't have it. - George Bernard Shaw

12th August 2003, 08:04 PM	#2
Goshawk Graduate Poster Join Date: Jan 2003 Location: Decatur, Illinois, USA Posts: 1,453	http://money.howstuffworks.com/credit-card3.htm Quote: If the ATM isn't accepting your card, your problem is probably either: A dirty or scratched magstripe An erased magstripe (The most common causes for erased magstripes are exposure to magnets, like the small ones used to hold notes and pictures on the refrigerator, and exposure to a store's electronic article surveillance (EAS) tag demagnetizer.) The problem with your card is probably "dirt", which the baggie covers up.