What is a GS1-128 barcode, and how is it structured?

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The GS1-128 is an application standard that not only encodes data but also provides a method of defining the meaning of the data. By using Application Identifiers (AI) it provides information about the structure and the meaning of the encoded data.

Application Identifiers are mostly used in industry-specific barcode symbologies. Manufacturers, distributors, suppliers and carriers in a number of industries use the GS1-128 barcode to mark pallets with transport and pallet labels. It is used in supply chains worldwide as part of GS1’s global standards.

An Application Identifier is a 2 to 4-character prefix used to identify the meaning and the format of the data that follows. AI’s have been defined by GS1 for identification, traceability data, dates, quantity, measurements, locations, bank account data and many other types of information.

The GS1-128 barcode by itself was developed to provide a global standard for exchanging data between different companies. AI’s are listed on GS1’s website, but you can download a nicely formatted PDF with them here. (AI List in PDF format).

GS1-128 table.pdf

The GS1-128 barcode is made up of these components:

  1. Code 128 start character (START-A, START-B or START-C)
  2. Code 128 FNC1 character (FNC1 is a flagging character)
  3. Application Identifier (AI)
  4. Encoded Data
  5. Symbol Check digit
  6. Stop Character.

GS1-128 Barcode Shipping Label

Although you could use a GS1-128 barcode for anything an AI exists for, in global trade the standard will be used primarily for shipping goods. The primary purpose of using GS1-128 shipping labels is to match a shipment with data being exchanged via EDI (if you don't know what EDI is, here is a great information source). GS1-128 can contain information that provides traceability. In addition, it makes inventory management easier and provides more efficient handling when transporting.

GS1-128 usually contains more information than a standard EAN/UPC code about what’s on the pallet. For example, it might include SSCC, GTIN, GSRN, GIAI, expiry dates, and batch numbers.

GS1-128 shipping labels are commonly broken down into pre-defined zones. Each zone normally contains either text or barcode information. Zones can be merged or left empty.

The bottom zone (Zone I) is commonly used to host the SSCC-18 barcode, which is a supplier assigned license plate and normally tied to an EDI document referencing all the carton contents. In addition to using the SSCC-18 barcode, many retailers use a Destination barcode in Zone G.

To be compliant with the GS1 General Specifications, all the barcodes on the label should be GS1-128 symbols. An Application Identifier is used to specify the data format and purpose for each zone. Fields such as a Purchase Order, Ship To location and sometimes also item information are on many GS1-128 Shipping Labels.

Since data being received and transmitted by EDI are essential components of a GS1-128 Shipping Label, a company’s EDI solution will determine which GS1-128 Solution is needed.

An example: creating a GS1-128 barcode for the shipment of Belgian “pralines” (chocolates filled with fresh cream)

  1. In Barcode Producer, select GS1-128
  2. Enter New, add AI 00 which is the AI for Serial Shipping Container Code
  3. Enter that code in the next field
  4. Enter New, add AI 17 which is the AI for an expiration date
  5. Enter the 6-digit YYMMDD expiration date
  6. Enter New, add AI 310y which is the AI for net product weight.

Enter the product net weight in kg. And presto, you’ve just created a perfect GS1-128 barcode. Enjoy!

Barcode Producer for Mac/PC creates perfect barcodes for retail packages, labels, books, packages, and everything else.

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