How does a magnetic stripe on the back of a credit card work?
817668
The magnetic stripe is encoded with the card number; there is also other informtion encoded as well, which may include any limit the bank places upon purchases with the card, and the card's expiration date.  The encoding itself isn't too different from the encoding used on old-fashioned tape drives that computers relied upon before disks.  The card reader gathers this information when you swipe it through on an ATM machine, gas pump, or similar device, then "talks" with the appropriate bank to make sure that the customer is not over their credit limit, or that the card is still valid and has not been lost or stolen.  If everything checks out, the transaction goes through, and you get your cash, or gas, or purchase.
137329
This is a very open question.  There is an algorithm called LUN10 that does some very simple checking to verify that a credit card is a valid card number.  It is also capable of identifying what card type a credit card is.\n\nHowever, to actually verify that a credit card is valid (including AVS checking, etc), would require interfacing with a credit card processing company.  VeriSign offers an XML interface to their credit card processing gateway.  You might want to look into that if that is what you are asking.
977398
you get a card based on you past payment history.  Pay it by the terms or they take your card.
520847
The credit card was the successor of a variety of merchant credit schemes. It was first used in the 1920s, in the United States, specifically to sell fuel to a growing number of automobile owners. In 1938 several companies started to accept each other's cards.\n\nThe concept of using a card for purchases was invented in 1887 by Edward Bellamy and described in his utopian novel Looking Backward. Bellamy uses the explicit term "Credit Card" 11 times in his novel (Chapters 9, 10, 11, 13, 25 and 26) and 3 times (Chapters 4, 8 and 19) in its sequel, Equality.\n\nThe concept of paying merchants using a card was invented in 1950 by Ralph Schneider and Frank X. McNamara in order to consolidate multiple cards. The Diners Club produced the first "general purpose" charge card, which is similar but required the entire bill to be paid with each statement; it was followed shortly thereafter by American Express. Western Union had begun issuing charge cards to its frequent customers in 1914.\n\nBank of America created the BankAmericard in 1958, a product which eventually evolved into the Visa system ("Chargex" also became Visa). MasterCard came to being in 1966 when a group of credit-issuing banks established MasterCharge. The fractured nature of the US banking system meant that credit cards became an effective way for those who were travelling around the country to, in effect, move their credit to places where they could not directly use their banking facilities.\n\nThere are now countless variations on the basic concept of revolving credit for individuals (as issued by banks and honored by a network of financial institutions), including organization-branded credit cards, corporate-user credit cards, store cards and so on.\n\nIn contrast, although having reached very high adoption levels in the US, Canada and the UK, it is important to note that many cultures were much more cash-oriented in the latter half of the twentieth century (Germany, France, Switzerland, among many others). In these places, the take-up of credit cards was initially much slower. It took until the 1990s to reach anything like the percentage market-penetration levels achieved in the US, Canada or UK. In many countries acceptance still remains poor as the use of a credit card system depends on the banking system being perceived as reliable.\n\nIn contrast because of the legislative framework surrounding banking system overdrafts, some countries, France in particular, were much faster to develop and adopt chip-based credit cards which are now seen as major anti-fraud credit devices.
554093
If the card, held up to a particular device, opens a door, it's probably an RFID badge (Radio Frequency Identification).  It's a contactless identifier, which means you don't have to physically touch the reader, so you can leave the badge on your sleeve, in your purse, or wherever, and still operate the door.  They're pretty common, and a web search for "RFID" will yield a ton of information on the subject.
272675
Actually I have tried this, It is very difficult to erase a credit card with incidental contact with magnets. Audio video and floppies, Just think about it and they are gone!
717653
The stripe is to indicate pin 1 on the cable to ensure you install it the correct way round ( 1->1 ) as not all cables have the keyway / notch or pin missing to ensure you fit the correct way around. Pin 1 is often marked on the device or board by a number 1 or dot, the cable connector usually has a little triange also to identify pin 1.
432322
a mix of the rubber cement and sticky note glue.  Maybe you can try to find out from the credit card company to the company that print them up the company that formulates it.
642659
Virtual Credit Card\n\n\n\nThis Card is specifically designed for use in remote shopping environments like the internet, mail order and telephone order transactions.\n\n\n\n\n\nSecurity \n\nFor your protection, this card has a low limit, does not have a magnetic strip or a signature panel and cannot be used at retail outlets or for cash advances
143016
It is likely that the card contains a magnetic strip with digital identification data that is read when you swipe it.  If the gate program recognizes your card as authorized to open the gate, a signal is sent to the gate operating mechanism to open the gate (and reclose it after you pass).
530281
All credit card companies are associated with a bank.  If you don't know the name of the bank that issues your card, it should be printed on the back of the card itself.  Write a letter to your credit card company and send a copy to the regulator of your bank.  The regulator will require that your bank/credit card company respond to all of your complaints and will require that the bank send a copy of the response to them as well.  If either you or the regulator is dissatisfied with the response, your credit card company/bank will need to take further action.\n\nIf your bank is a national bank, write to the Office of the Comptroller of the currency.\n\nIf your bank is really a thrift (savings and loan) write to the Office of Thrift Supervision.\n\nIf your bank is a state member bank, write to your local Federal Reserve Bank.\n\nIf your bank is a state non-member bank, write to the Federal Deposit Insurance Corporation.  \n\nAnd if your bank is a credit union, write to the National Credit Union Association.\n\nDon't worry about picking the wrong regulator.  If you send your letter to the wrong one, they'll let you know who you should write to.\n\nYou should know, too, that it is illegal for your financial institution to take any kind of retaliatory action against you for "exercising your rights under the Consumer Protection Act".
1172248
It's the security code printed on the back of your credit card / bank card.
73613
A merchant takes you information (electronically or another method), gets verification of your information and tells the store clerk to let you out of the store with the stuff you want.  Then the merchange transmits a file to the credit card processing company who then pays the merchant.  You then get a bill for what you bought and you pay the bill.\n\n[source - 1 year working in operations for the merchant credit card processing division of Citicorp]
797370
a magnetic card reader
537555
WOW!!!\n\nI have NO idea how it's done but it sure works ---- unless everyone chooses the same card??? I can't see how that could happen tho - thanks for the link :-)
39201
Chargebacks occur for different reasons.  Below are a few chargeback prevention tips:\n\n1) Obtain a signature for every transaction if possible.\n2) Utilize AVS (address verification) for all non face to face transactions.  Your credit card machine should be programmed to ask for the billing address and zip code of the card holder.  This does not guarantee that you won't get a chargeback, but it does cut down on fraudulent card activity.\n3) Do not accept the card if the customer is not the cardholder.\n4) Check the customer's signature against the signature on the back of the card if face to face.\n5) Obtain a signed proof of delivery when shipping products to customers.\n\nYou may want to contact your merchant service provider and ask them to assist you with your merchant account if you are having chargeback issues.  They should be able to give you some advice.
1186750
WHAT THE HECK DOES THIS HAVE TO DO WITH CREDIT