It is not intended to be used for data to be scanned at the point of sales in retail outlets. Character set C enables numeric data to be represented in a double density mode. Here, two digits are represented by only one symbol character saving valuable space. Code 128 symbols use two independent self-checking features which improves printing and scanning reliability. This combination allows all participants in the supply chain to use a common, standard solution for their individual tracking and tracing needs.
AIs are prefixes which indicate the meaning and format of the data which follows.
They may be used for, amongst other things, item identification, measurements, quantities, traceability, dates, transaction references and location numbers. Version E, the zero suppressed version, is a six digit code used for marking small packages. Version D, the variable length version, is not commonly used for package marking. It is used in limited special applications. Both Version A and E may include either a 2 digit or a 5 digit supplemental encodation.