Magnetic Stripe technology is one of the most universal methods in Automatic Identification and Data Capture (AIDC) industry. This technology is very much established and has been developed for quite a long time. Magnetic stripe technology is used everywhere. People use cards with this technology on them without even aware of it. The technology is embedded in credit cards, ID cards, ATM cards, security control of selected rooms or buildings, time and attendance cards, factory floor data collection cards, driver's licenses, mass transits tickets, airline tickets and many more.
Magnetic Stripe Technology is known as a handy and cost-effective way of carrying a practical amount of rewritable and machine-readable data using magnetic storage technology. Even though the technology has been used for many years, there are still many new things going on in the industry, in terms of its innovations and developments.
Magnetic Stripe is very much alike to VCR or floppy disk technology. It uses magnetic material to store data. The difference between VCR and magnetic stripe technology is that magnetic stripe is printed on paper or plastic, and it stores data instead of sound and images. Magnetic stripe cards are designed to be directly handled and they are often used for reading by manually swiping. The two most essential factors affecting the magnetic recording and replay process are head to medium partition and traveling speed of the medium.
Magnetic Stripe Technology was first used in the early 1960's. The London Transit Authority installed a magnetic stripe system in the London Underground. During late 1960's, BART (Bay Area Rapid Transit) began to install a paper-based ticket, which has the same size as a credit card. The systems used a store value on the magnetic stripe, which was read and rewritten every time it was used. (AIM Global, 1999)
Even though credit cards were already used in 1950's, it wasn't until 1970 that the magnetic stripe became a feature in the cards. Nowadays, all credit card manufacturers follow ISO standards on data formats so that every person can utilize magnetic stripe cards around the world without concerning the incompatibility and security issue
Magnetic stripes come in two versions, the normal credit card version and the high-coercivity (HiCo) version. The HiCo version enhances reliability by reducing the chances the data being deleted or damaged unintentionally. Coercivity is defined as the strength of the flux reversals in the magnet, or in other words the resistance of the material to demagnetization. This is the most important characteristic in determining what kind of material to use as the stripe. When a magnet is demagnetized in magnetic stripe, the data encoded is lost or distorted. Therefore, the higher the coercivity of the material, the less chance the magnetic stripe in becoming damaged. However, the higher the coercivity of a material, the more expensive it is.
The unit of measure for coercivity is Oersted (Oe). The lower the Oersted value, the lower the coercivity, vice versa. The typical range of coercivity of the material used is from 300 Oe to 4000 Oe. The ANSI standard for coercivity for magnetic stripe is 300 Oe. (University of Pittsburgh, ADC, 2000)
The material used depends on what types of functions the card will serve. If the magnetic stripe is demanded to be the most rugged, material used would have a coercivity of around 3000 Oe. On the other hand, if the card has a short life cycle, the less coercivity material is used. The most broadly used material in the industry is called Gamma-Ferric Oxide, which has coercivity of 300 Oe.
The parts of a magnetic stripe card are consisted of two parts, the substrate and the media. (Keele, 2000)
Substrate is the part that provides stiff and robust backing onto which the thin film of magnetic media is deposited. The designed application of the magnetic stripe determines which material used for the substrate. For cheap and high volume applications such as single-journey public transport tickets, thin paper-based materials can be used. For longer time type of applications, more durable material is used. For example, for credit cards or ID cards, synthetic laminates are used as substrates.
Magnetic media can be divided into two types, particulate and continuous media. Particulate media include gamma-ferric oxide, cobalt modified gamma-ferric oxide, chromium dioxide, metallic iron and barium ferrite. Continuous media include cobalt-phosphorus, nickel-cobalt-phosphorus, cobalt-chromium thin metallic films. Magnetic domains in particulate media serves as small magnet, which can be magnetized in one of two opposing directions by an electrically induced magnetic field. (Keele,2000)
There are two manually operated readers, which are through swiping and inserting cards.
Swipe readers have a slot where a magnetic stripe card is dragged past a stationary read head. This type of reader let the individual to keep full control of the card at all times. However it will not perform well if the card is dragged too slow or too fast.
Another type of reader is by inserting the card. Usually, the card is 'swallowed' by the reader and reading takes place by either passing a head over a stationary card or the card over a stationary head. This system gives constant reading and writing speed and control over head to media distance. This system is best if higher data densities are an important factor of the design.
Some disadvantages of using magnetic stripe cards:
The standards of magnetic stripe have been developed in two main parts: physical and application standards. Physical standards identify the locations of recording track, encoding methods, data densities and magnetic recording qualities. Application standards deal with content of data and data format for different applications.
Standardization of magnetic media
The standard of magnetic media is for conventional low coercivity media and can be utilized as a benchmark against other media using a conversion factor. The standard requires the clearly defined procedure in ISO 7811.
Standardization of data encoding
As mentioned above, data is encoded onto magnetic media in the form of flux reversal that form a digital binary pattern. It can take the form of binary code, ASCII representation or any other suitable form of coding or encryption. There is only one widely used symbology called Aiken Biphase or F2F. In this symbology, a track on magnetic stripe is divided long ways into a number of pairs of zones. If a flux reversal occurs between 2 zones within a pair, it is interpreted as binary one. If no flux reversal occurs, it denotes zero. Therefore, there is always be a flux transition between the two zones that forming a bit. (Keele, 2000)
Compared to magnetic stripe, smart card is more secure to be used. By having chip on the card, smart card protects the information stored from damage or theft. Current magnetic stripe cards have limited capacities to copy information.
By using smart cards that have greater capacity, customer profiles can be broader and information can be easily added or deleted from the memory. In addition, smart card can perform decision making due to the powerful processing capabilities, such as data encryption.
As mentioned above, magnetic stripe applications range from credit/debit cards, employee ID cards, driver's licenses, ATM cards to paper tickets for airlines, buses, trains, subways. The application that gains big momentum is stored value cards. The card is purchased beforehand and encoded with a specific value. Then, it is used to purchase goods or services. The value of the card is magnetically decremented with each usage. Two main typical applications are telephone toll calls and mass-transit tickets.
Magnetic Stripe Cards are widely used as well in managing time and access. One area used is in manufacturing shops and warehouse floor. If bar codes are mostly used in industrial applications to identify and track the movement of inventory, magnetic stripe cards do essentially the same tasks when we deal with people rather than inventory. It can identify people to a data collection system. It can then be used to record the individual's time and attendance. In addition, it can control access to particular area in the shops and warehouse floor. Besides the easiness of the card, it also provides excellent data flexibility. The information can be changed using a standard encoder.
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