Overview of GS1 Composite

A composite barcode consists of a one-dimensional barcode below a two-dimensional barcode with a separator pattern between them. The one-dimensional component encodes the primary item ID number using the GS1 system of identification numbers. The two-dimensional component encodes secondary data such as expiration date or batch number.

The one-dimensional part can be GS1-128 (UCC/EAN-128), EAN/JAN-8, EAN/JAN-13, GS1 DataBar Limited, UPC-A, or any member of the GS1 DataBar and GS1 DataBar Expanded families.

The two-dimensional component is always the CC-A, CC-B, or CC-C symbology. If the one-dimensional component is any symbology other than the GS1-128 (UCC/EAN-128), the label printing software must use CC-A for the two-dimensional part when the data is less than 57 characters; for data streams greater than 57 characters, it must use CC-B. Users can choose to use CC-C when the one-dimensional component is GS1-128 (UCC/EAN-128).

GS1-128 & CC-C

All composite symbologies have these characteristics:

The character set, for both components, includes upper and lower case letters, ten digits, 21 punctuation characters (! " % & ' ( ) * + , - . / : ; < = > ? _ <space character>), and FNC1.

The data stream also includes a "|" character, separating the primary data from the secondary data. Good quality label printing software will insert the "|" automatically. It appears as a separator pattern in the barcode, and does not appear at all in the human readable part. In the example below of an GS1 DataBar Limited with CC-B composite, there is a "|" in the data stream just before the "21" at the beginning of the secondary data. The "7" at the end of the primary data is a check digit and the "01" at the beginning is an implied application identifier. So the actual data stream is: 1501234567890|21abcdefghijklmnopqrstuv.

The one-dimensional component has the full data capacity of the underlying linear symbology. The capacity of the two-dimensional component is 56 characters for CC-A, 338 for CC-B, and 2,361 for CC-C.
The barcodes are bi-directionally readable.
The one-dimensional component has one check digit and the two-dimensional component uses Reed-Solomon codewords.
Both components contain a linkage flag indicating that they are part of a composite.