Application Identifier (GS1)

An Application Identifier (GS1) (AI) is a 2,3 or 4 digit number, that indicates the meaning (or status) of the data, which immediately follows the Application Identifier (GS1). It is only used with GS1 data carriers, such as GS1-128 and CS1 DataMatrix bar codes. 

This supporting information is also known by these names:
ContextAlias
shortnameAI
alsoknownasApplication Identifier