How to Encode Magnetic Cards

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Magnetic-stripe cards are all around us, from credit and debit cards to ID cards used by students and professionals. These cards use arrays of magnetic particles in a black or brown stripe to store digital information in binary form, with the orientation of the particles determining whether each is read as a one or a zero. Several formats are commonly used on magnetic-stripe cards; the most common is ISO 7811, types one through six. Most card readers can write to this format, and most are capable of writing three "tracks" simultaneously (some have as many as six independent tracks, on which different information may be written simultaneously).

Install the software included with the card encoder on the desktop or laptop you will use to write cards. The software typically comes as a disk which, when inserted into your computer, will install the software automatically. Follow all of the instructions that come up on the screen after you insert the disk.

Connect the card encoder to the computer on which you have installed the encoder software. Most encoders interface with the computer via a universal serial bus (USB) port. These are common to all personal computers and are the same type of port used to interface with external memory devices like thumb drives and external hard drives. Your computer should alert you that a new piece of hardware has been installed, and a small light may illuminate on the card encoder to signal that it is functioning.

Open the card encoder software. You should see a window with several text boxes (corresponding to the tracks the encoder can write simultaneously) in which you can enter the information you wish to be encoded onto the card. Enter the appropriate data into the text boxes, then click the "Write" or "Encode" button in the window. Immediately swipe the blank card you wish to write to through the slot in the encoder in the orientation indicated by the included instructions. The card should now be encoded.


  • The software will include options to encode the information as "high-co" or "low-co," referring respectively to high and low "coercivity." Cards that can be encoded at a high coercivity are less likely to have the information stored on them degrade or be erased by magnetic fields.


About the Author

Paul Bragulla began writing professionally in 2010, producing online articles. His experience as a researcher in beamed energy propulsion means that he can write knowledgeably about topics such as optics, laser operation and high-speed photography. Bragulla holds a Bachelor of Science in physics from Rensselaer Polytechnic Institute.

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