How does the magnetic stripe work?
A. The end-user defines the requirements for the magnetic stripe including the signal amplitude expected, the coercivity of the stripe, the encoding method and the bit density. The card manufacturer uses the first two points to select the type of magnetic material to use. The system designer is concerned with all four of the parameters. As explained above, the stripe is made from many small particles bound together in a resin. The density of the particles in the resin is one of the controlling factors for the signal amplitude. The more particles there are, the higher the signal amplitude. The density (or loading) combined with the thickness give a method for controlling the amplitude. Signal amplitude is important because it defines the design of the readers for the cards. Standards exist (ISO/IEC 7811) which define the signal amplitude for cards that are used in the interchange environment (such as banking). By conforming to these standards, a user ensures that the magnetic stripe can
