What's with that magnetic strip, anyway ?

On many cards such as credit cards, membership cards and so on, there's a blackish strip on the back. This is magnetic, which one easily realize, since it has a tendency of becoming de-magnetized at the most inappropriate time.

But what's really on that strip ? I made a little research, and this is what I found.

The strip has three separate tracks on it. They are 0.11 inches wide and follow the ANSI/ISO standard 7811, when it comes to density and number of bits per character. This is what's on each of them:

Track 1, total of 79 characters, developed by the International Air Transportation Association, IATA :

Track 2, total of 40 characters, developed by the American Bankers Association, ABA :

  • Start, 1 character.
  • Account Number, 19 chars.
  • Separator, 1 char
  • Country Code, 3 chars
  • Expiration Date or yet another separator, 4 or 1 chars.
  • Fill out so the total will be 40 characters.
  • End, 1 char.
  • Check Character, 1 char.

Track 3 is a read/write track, which is used for PIN-codes and other information. It can contain up to 107 numeric characters.

Facts from "Howstuffworks" Who made a softlink to Apocalypse Now down there ?