Introduction to the basics of crossing 25 yards

Code 2 of 5 Interleaved (ITF25 code). It was invented by the American company Intermec in 1972. Early widely used in warehousing and heavy industry. In 1981, the United States began to use it in the field of transportation packaging. In 1987, Japan introduced the cross 25 bar code, which was used for the identification and management of storage and transportation units after standardization. The EAN specification will cross 25 bar codes for storage and transportation units of the standard bar code. Cross 25 bar code is a high density bar code.

Since both bars and blanks represent information, there is no bar code character interval. Therefore, it is a continuous bar code. Because it represents different number of numeric characters, it is a non-fixed length bar code. Cross 25 bar code is prone to misreading caused by information loss. When the scan path does not pass through two blank areas, it is easy to start or end the bar of a bar code symbol with blank space, which will cause information loss or decoding error.

Therefore, cross-25 bar codes are often used to identify fixed length characters. At this time, decoder or computer only receives fixed length information, short data information can be added at the beginning of the "0" character to achieve a fixed length. In addition, a protection frame is often used to prevent incomplete scanning and number misreading.

The characteristics of the code system of the cross 25 bar code:

1. Decidable character set: digits 0-9 (including 48-57 in ASCI II characters, consistent with GB/1988);

2. Code type: continuous;

3. Each symbol character is composed of 5 units, namely 2 wide units and 3 narrow units, encoded as 5 bars and 5 blanks;

4. Character self-check

5. Length of codable data string; Variable (even number of digits);

6. Two-way decoding

7. Symbol validator: one

8. Symbol character density, according to the width and width ratio, each symbol character pair is composed of 14-18 modules;

9. Non-data part, 8-9 modules according to width ratio.

Cross 25 bar code symbol structure:

1. Left blank area

2. The starting character

3. One or more symbol character pairs representing data (including optional symbol validators)

4. Termination

5. Blank area on the right