How to encode credit cards
Magnetic Stripe and Barcode Encoding
The ubiquitous magnetic stripe is a dark magnetized metallic strip on the reverse side of PVC cards. It is used to contain small amounts of data such as an account number or expiry date. Its popularity stems from the fact that it is not human readable - a special reader such as a wipe reader is required to decipher the encoded data.
There are three tracks of data in a magnetic stripe. Each track is .110-inch wide. The ISO/IEC standard 7811, which is used by banks, specifies:
- Track one is 210 bits per inch (bpi), and holds 79 six-bit characters plus parity bit read-only characters.
- Track two is 75 bpi, and holds 40 four-bit characters plus parity bit characters.
- Track three is 210 bpi, and holds 107 four-bit characters plus parity bit characters.
Coercivity is a term applied to describe the quality (or strength) of magnetic stripes. It is a measure of the strength of magnetic field required to affect the encoded data on a stripe. There are 2 standard levels of coercivity commonly available: HiCO and LoCO.
HiCO cards, or High Coercivity, provide the highest level of protection to the encoded data from stray magnetic fields. Conversely, HiCO cards are harder to encode and are slightly more expensive. Typical uses are credit/debit cards and entry/exit cards.
LoCO cards, or Low Coercivity, are less expensive and easier to encode. In extreme conditions data can more easily be lost. Typical uses are cards that are not frequently read, for example membership cards.
Most card printers require additional print modules to encode HiCO and LoCO magnetic stripes. CardFocus can send magnetic stripe data to printers for all 3 data tracks.
There are two commonly available types of barcodes, linear (1D) and 2D. Linear barcode symbols are easily identified by their tall printed bars of varying widths. There are many linear symbols but the ones used
most frequently are called UPC-A, UPC-E, EAN-8, EAN-13, Code 39, Code 128, and ITF (Interleaved 2-of-5). Two dimensional barcode symbols look like multi-row barcodes with very short bars stacked on top of each other.
CardFocus enables coding of alphanumeric data only to linear barcodes. In addition to alphanumeric data, CardFocus permits the encoding of small photos, fingerprints and signatures to 2D barcodes. The type of 2D barcode supported by CardFocus is referred to as PDF-417.
The CardFocus barcode module send barcodes to the printer as bitmaps. These can be read by barcode readers that operate in the visual light frequency (e.g. VLID-II).
Below is a complete list of the barcode symbols supported by CardFocus. If a required symbol is not listed here, then the True Type font for that symbol can be installed with CardFocus. In this way, the encoding is performed through the application of the barcode font to the ata to be encoded.
- Code 128: Full ASCII-Character set with Code128 ABC autoselection
- Code 128A: Char Set A: Capital letters and special characters
- Code 128B: Char Set B: Letters in upper and lower case
- Code 128C: Char Set C: Optimized for numbers
- EAN 128: Special form of the Code 128 also known as UCC/EAN 128
- EAN 13: European-Article-Number with 13 digits
- EAN 8: European-Article-Number with only 8 digits
- EAN 5: Add on price code for ISBN
- EAN 2: Add on found on newspapers
- ISBN: International Standard Book Number
- UPC A: Universal Product Code with 12 digits
- UPC E: Short form of the UPC
- Code 39: Also known as Code 3 of 9
- Code 39 Extended: Also known as Code 3 of 9 Extended
- Code 25: Also known as Code 2 of 5
- Code 25 Interleaved: Also known as Code 2 of 5 Interleaved
- Codabar: Often used for medical purposes
- Code 93: Numbers, uppercase letter and -. * $ / + %