code 2/5
The Code 2/5, Code 2 of 5, is a numeric bar code with which the digits 0 to 9 can be represented. The individual digits of the code 2/5 are formed from bars and gaps, namely three bars and two gaps. Code 2/5 is a two-width code in which each bar and each gap can be represented narrow or wide. The ratio between narrow and wide bars or gaps is 1:2 or 1:3.
The designation code 2/5 comes from the fact that the information consists of five information units of bars (S) and gaps (L). In this case, the information content is formed by four strokes and gaps (1-2-4-8). The wide strokes/gaps represent a digital "1", the narrow ones a "0". The fifth bar forms the checksum, which must always be 2. With these specifications, a Code 2/5 barcode looks like this: S0- L0-S1- L1-S0 (checksum). The beginning of Code 2/5 is marked by a start character, the end by a stop character. Code 2/5 uses modulo 19 with weight 3 as checksum method.
A variant of Code 2/5 is Code 2/5 Interleaved. In this code, the digits are interleaved one after the other. The information content is in the bars and in the gaps. The digits to be assigned to an odd digit are coded with dashes, those to an even digit with gaps. Four dashes (gaps) form the digit, the fifth dash (gap) the parity bit. The first digit is represented with five dashes - 4 information bits, 1 check bit -, the second with the intervening gaps, the third with dashes, the fourth with gaps, and so on. As a result, the code 2/5 Interleaved has a high information density.
Code 2/5 Interleaved has the same character set as Code 2/5, but differs in that it can be of any length, but must be even-numbered because each individual digit must always have even parity. Code 2/5 Interleaved is used in logistics and by parcel services, in department stores, and in the food, pharmaceutical, and electronics industries.