Bar code is a symbol that combines lines and blanks according to certain coding rules to represent certain letters, numbers and other information. in the time of identification, it is scanned by the barcode reader to get a set of reflected light signal, which is transformed into a set of electronic signals corresponding to the lines and blanks after photoelectric conversion, and then reduced to the corresponding text numbers after decoding, and then transmitted to the computer.

   Encoding technology of barcode card.  

- UPC code 

The U.S. is the first to apply in the domestic commercial system. The code system is mainly used in commercial systems. The code length is fixed at 12 bits. 

- EAN Code 

The countries of the European Economic Community have developed the European Article Code EAN code in accordance with the UPC code standard. there are two types of EAN codes: EAN-13 codes and EAN-8 codes. 

- interleaved 25 Code 

interleaved 2 of 5 Code is a continuous self-checking numeric code system with variable length. 

- Code 39 

39 Code (Code 3 of 9) is a variable length discrete self-checking alphabetic code system, 39 code is now the most common code system used in barcode card making. 

- Kudelba code (codabar) 

The codabar code is a variable length discrete self-checking numeric code system. It is commonly used in the management of warehouses, blood banks and air courier packages. 

- 128 code (Code128) 

128 code (Code128) is a variable-length continuous alphanumeric code system. 

   Common barcode types are.

EAN 8

EAN 13

Code 39 -- 39 code

Code 128 -- 128 codes

Code 25 -- 25 codes

UPC Code

   Barcode card market.