Magnetic stripe technology is well known. Magnetic stripe is typically used for:

• Credit and bank cards,
• Debit cards,
• Transit tickets (bus and subway fares),
• Airline tickets and boarding passes,
• Prepaid (stored) value cards, and
• Access control cards.

Magnetic stripe recording is very similar to audio and video recording. The basic differences, of course, are that the magnetic material is applied to a paper or plastic card or ticket and data is stored on the stripe instead of sound or images. Information can be recorded, read, and re-recorded many times.

Within the magnetic stripe are particles that can be magnetized by proper writing equipment. Each particle is given a magnetic polarity (e.g., N-S). During reading, the orientation of the magnetic field of each particle is determined. Where particles with the same polarity are next to each other (e.g., N-S and N-S), these particles form, essentially, a long "single" magnet. However, when particles with opposite polarities are next to each other (e.g., N-S and S-N), the magnetic field reverses, creating what is called a "flux reversal." These flux reversals are detected by the reading equipment.

Data is recorded in "tracks" in much the same way sound is recorded on audio casettes. Multiple tracks are available on each stripe and multiple stripes may be used on a card or ticket to increase data capacity. There are three track locations on a standard credit or ATM card.

Although financial transaction cards are the best known application, there are many other uses for magnetic stripe cards and tickets including video games and key access. Track locations and data format for these applications do not necessarily follow the same standards as do financial cards.

In the past, magnetic stripe materials could be damaged by powerful refrigerator magnets and other common sources of magnetic fields. Today, however, high coercivity magnetic stripe media is available that is virtually immune to inadvertent magnetic damage (although using a magnet to put your credit card on the refrigerator is still a bad idea).

Magnetic Stripe Standards
International standards have been established for

• Materials (of stripe and cards),
• Stripe locations (on cards and tickets),
• Track locations (on stripe), and
• Data encodation methods.

Magnetic Stripe Advantages:

• Read/write capabilities,
• Relatively high data density,
• Security against casual counterfeiting,
• Reliability, and
• Low cost-per-use.

Magnetic Stripe Limitations:

• Contact reading,
• Initial cost per card, and
• Potential magnetic damage to low coercivity stripes