GS1 uses a system of Application Identifiers (AI) to capture additional information in barcodes.
These numbers are used to identify the different data attributes which can then be split into their individual components by the scanning software.
You can spot AIs as the numbers that appear in brackets next to barcodes such as the GS1-128 and GS1 DataMatrix.
Below is a list of some of the the most common identifiers:
| AI | Description | Data Format | ||
|---|---|---|---|---|
| 01 | Global Trade Item Number (GTIN) | 14 digits - numeric | ||
| 10 | Batch/Lot Number | 1-20 - alphanumeric | ||
| 11 | Production Date | 6 digits: YYMMDD | ||
| 17 | Expiration Date | 6 digits - YYMMDD | ||
| 21 | Serial Number | 1-20 - alphanumeric | ||
| 00 | Serial Shipping Container Code | 18 digits - numeric |
Each Application Identifier has a specified format, including how long the data field is and what characters can be encoded. For example, GTIN and dates are predefined (fixed) numerical lengths whereas the Serial Number, Batch/Lot and Consumer Product Variant are non-predefined (variable) lengths.
When entering AI, it’s important to know that predefined fields such as the GTIN and dates, should ideally be captured before non-predefined fields.
Below is a GS1-128 barcode with the defined length AIs (GTIN and use by date) encoded before the non-predefined AI (batch).
There are occaisions where two non-predefined length data elements are required to be encoded in a barcode. To ensure that machines reading barcodes clearly distinguish the beginning and end of non-predefined components, the FNC1 character should be used as a data separator.
Section 3 of the General Specifications has a full list of Appliation Identifiers, including details of the AI which require the FNC1: