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Magnetic Stripe Cards


Magnetic Stripe Cards Physics Structure.

In general, magnetic stripe on card has 3 tracks, they are track1, track2 and track3. Every track records different data, these data have different use. Besides, some magnetic stripes just have 2 tracks, even 1 track. In general application systems, all the 3 tracks, 2 of 3 tracks or 1 of 3 tracks is used according to actual situation.


The size of above picture conform to physics size definition of ANSI and ISO/IEC standards. These size definitions concern standardization of magnetic stripe card readers or writers. Because when you encode on track1, track2 or track3, if the data’s position on the magnetic stripe is several millimeters higher or lower than standard position, the data excurses to another track. The width of 3 tracks are the same, it is about 2.80mm, the width of the gap between the 2 adjacent tracks is about 0.05mm, the gap is to detach adjacent tracks; the whole width of magnetic stripe is about 10.29mm( if it is the magnetic stripe with 3 tracks), or is about 6.35mm(if it is the magnetic stripe with 2 tracks). Actually, the width of most cards like bank cards is widened by 1~2mm, the whole width is between 12 and 13mm. 

On magnetic stripe, the beginning position and end position of data recorded on 3 tracks is not on the edge of magnetic stripe, beginning position is 7.44mm from right edge, and end position is 6.93mm from left edge; these standards are to protect recorded data from losing easily, as magnetic stripe edge area is easier abrasion than the middle area.

Standard definition of tracks

Application distribution of tracks are made as per actual use requirements, such as bank systemsecurities systemaccess control systemidentity recognition systemdrivers license management system and so on, all these systems have different application format requirements with 3 tracks. Here, wed like to discuss the standard definition of 3 tracks on the bank cards that conform to international current bank/finance application systems, these definitions are also extensively used by visa credit cardsmastercard credit cards and other bank cards.

Track1: its original standard definition was made by IATA(International Air Transportation Association). The numbers and letters on track1 record automatic information in air transportation, for example, goods label informationdealing informationbooking tickets information, and so on. These information is deal with by special readers/writers, and there is a application system in airline to work for them. Application system has a database where all data on magnetic stripe cards can be found.

Track2: its original standard definition was made by ABA(American Bankers Association). The definition has been used by a lots of bank systems. It includes some basic relevant information, like cards unique identifiervalid time and others.

Track3: its original standard definition was made by THRIFT. It mainly is used by some enterprises that need change information on magnetic stripe card. Typical use includes prepaid cards, debit cards and so on. This kind of use is usually off line, it means banks system is difficult to trace the data on magnetic stripe cards simultaneously. It appears as the data on track3 is different from that on bank system.

Letters and numbers allowed to use on 3 tracks

It usually use bit to code for 3 tracks. As per different track where data is, 5 bits or 7 bits make up of a byte.

Track1(IATA): record density is 210BPI; it can record numbers from 0 to 9 and letters from A to Z; track1 is able to record 79 numbers and/or bytes; every bytes make up of 7 bits.

Track2(ABA): record density is 75BPI; it just can record numbers from 0 to 9, track2 is just able to record 40pcs numbers; every number make up of 5 bits.

Track3(THRIFT): record density is 210BPI; can record numbers from 0 to 9, it is able to record 107pcs numbers; every number make up of 5 bits.

As track1 is able to record numbers and letters, so it usually records use typesscope and some other instruction information. For example, on bank cards, track1 records user name, cards valid date and so on.

And as track2 and track3 is just able to record numbers, they are usually used to record users account information and fund information and some other number information. 

In actual application, if we want to record other information, besides numbers on track2 or track3, like ABC, We usually express it as per international standard ASCII. For example, recording A on track2 or track3, we can use As ASCII no. “0x41 to express. 0x41 could use two numbers-- 4 and 1 to express on track2 or track3, they are 0101 and 0001