GS1 AI (Application Identifier) & Element String Specification Reference

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The GS1 Application Identifier (AI) appears after the Function Code 1 (FNC1) in GS1-128, DataBar Expanded, GS1-DataMatrix and GS1-QRCode barcode symbols to encode certain types of information. Multiple AIs may be encoded in a single symbol to allow, for example, serial numbers, sell-by dates and other information to be automatically evaluated at the point of sale.

When generating GS1 Symbols, the following rules apply:

  • The FNC1 character is not visible and is only available within certain barcode types.
  • The AI is defined by the digits after the FNC1 character, which must be the first character in a GS1 barcode.
  • The Element String is the combination of the AI and its data field.
  • Multiple fixed length element strings may be included in a single barcode symbol without additional FNC1 characters, if variable length element strings (such as those with AIs 10, 21 or 92 as defined below) are included last. This is because the reading device understands the length of each fixed length element string. IDAutomation offers an Element String Testing Tool that may be used to check multiple fixed length element strings.
  • If additional element strings are encoded after a variable length element string, an additional FNC1 is required between them to define the end of the variable length element string.

The following chart provides examples of common GS1 element strings as defined by the GS1 Application Identifier Specification (v16 2016) and should be verified by a GS1 Member Organization before implementation.

Chart 1. Popular GS1 AIs.

 Purpose AI Data Field Format (Fixed or Variable)
 SSCC-18 00 18 numbers: 17 digits + MOD10 check digit
 GTIN-14 01 14 numbers: 13 digits + MOD10 check digit
 GTIN-14 of contained items 02 14 numbers: 13 digits + MOD10 check digit
 Future assignment 03 14 digits
 Future assignment 04 16 digits
 Batch or Lot Number 10 Variable, up to 20 digits
 Production Date 11 6 numbers: YYMMDD
 Due Date 12 6 numbers: YYMMDD
 Packaging Date 13 6 numbers: YYMMDD
 Future assignment 14 6 digits
 Best before Date 15 6 numbers: YYMMDD
 Sell By Date 16 6 numbers: YYMMDD
 Expiration Date 17 6 numbers: YYMMDD
 Future assignment 18 6 digits
 Future assignment 19 6 digits
 Variant 20 2 number digits
 Serial Number 21 Variable, up to 20 characters
 Count of items 30 Variable, up to 8 numbers
 Trade Item Count 37 Variable, up to 8 numbers
 USPS 91 20 numbers: 19 digits + MOD10 check digit USPS Delivery Confirmation Service
 Intra Company Internal 90-99 Variable, alpha numeric internal use data up to 30 characters
 USPS 99 USPS Intelligent Mail Container Barcode
 GDTI 253 Global Document Type Identifier – up to 30 characters
 GCN 255 Global Coupon Number – 12 digits + MOD10 check digit
 Weight or dimensions 310-369 7 numbers (First number indicates the decimal point position)
 PO Number 400 Variable, up to 30 characters
 GINC 401 Variable, Global Identification Number for Consignment – up to 30 characters
 GSIN 402 Variable, Global Shipment Identification Number – up to 17 numbers
 Routing Code 403 Variable, up to 30 characters
 Shipping related 410-415 13 numbers: 12 digits + MOD10 check digit (GLN)
 Ship to 420 Variable, up to 20 digits
 Origin 422 3 digit ISO country code
 Net Weight in Kilograms 3103 6 numbers: AI is 310(n), where (n) indicates the decimal position
 Net Weight in Pounds 3202 6 numbers: AI is 320(n), where (n) indicates the decimal position
 Price 3922 Variable, up to 15 numbers: AI is 392(n), where (n) indicates the decimal position
 Price in ISO Currency 3932 Variable, up to 15 numbers: AI is 393(n), where (n) indicates the decimal position
 GRAI 8003 Variable, Global Returnable Asset Identifier – up to 30 characters
 GIAI 8004 Global Individual Asset Identifier, often used in DOD UID Labels.
 CPID 8010 Variable, Component/Part Identifier – up to 30 characters.
 GSRN 8018 Variable, Global Service Relation Number – up to 18 characters.
 Coupon Extended Code 8100 6 numbers
 USA Coupon Codes 8110 Variable, up to 70 characters. The DataBar Coupon Symbol consists of the company prefix, offer code and other data as defined by the Joint Industry Coupon Committee and GS1.
 Extended Packaging URL 8200 Variable, up to 70 characters.

Below are a few examples of GS1 barcodes encoding element strings.

Chart 2. Element string example encoding two defined length element strings.

 Element String Element String
 AI GTIN Field AI Expiration Date Field (YYMMDD)
 01 234567890123457 17 991231
 Data To Encode: (01)3456789012345717991231

GS1-128:

GS1-128 AI Example 1
GS1 DataBar Expanded:

GS1 DataBar Expanded
(01)34567890123457
(17)991231

GS1 Data Matrix:

GS1-DataMatrix AI Example 1
(01)34567890123457
(17)991231

GS1 QR Code:

GS1-QRCode Example 1
(01)34567890123457
(17)991231

Chart 3. Element string example encoding one defined length element string and two variable length element strings. The addition of parentheses around the AI of 21 will insert an additional FNC1 within the barcode symbol with the exception of GS1 DataBar, which requires the ASCII 202 character (Ê) to be inserted as a delimiter after the data of a variable length element string.

 Variable Element String Variable Element String
 AI Batch Field AI Serial Number Field
 10 3456789 21 3456789012
 Data To Encode: (01)34567890123457103456789(21)3456789012

GS1-128:

GS1-128 Variable Length Element String Example

GS1 Data Matrix:

GS1-DataMatrix Variable Length Element String Example
(01)34567890123457
(10)3456789
(21)3456789012

 GS1 QR Code:

GS1-QRCode Example 1
(01)34567890123457
(10)3456789
(21)3456789012

GS1 DataBar Expanded:

GS1 DataBar Element String Example
(01)34567890123457
(10)3456789
(21)3456789012

NOTE: When using DataBar Expanded, the ASCII 202 character (Ê) must be inserted as a delimiter after the data of a variable length element string. For example: (01)34567890123457103456789Ê(21)3456789012

Additional information regarding GS1 Identification Keys.