Structure of Field 11
Field 11 is defined by the Gateway Interface Specification as a user-defined field with a variable length (up to a maximum of 80 characters). Since Gateway does not modify this field, it allows the POS and Simplify to communicate with each other with no concern for how Gateway might affect the data.
For added flexibility, this field contains two data areas, a Command Area for non-tokenized data and a Token Area for tokenized data (“TAG Length Data Structure”). The following is a generic format of this field.
|Command Area||The format of fields in the Command Area depends on the Transaction Type (and Message Type for Transaction Type = 36). The Maximum Length of this area is currently 11 characters See Use of Command Area for details.||0||VAR|
|Field Separator||The character ‘?’ is used to separate the Command Area from the Token Area||VAR||1|
|Token Area||The Token Area contains Tokenized fields in the format “TLLDDD…” where
T = Token
LL = Length of Data
DDD… = Data (Length = LL)