UCC/EAN128^[2] encodes structured data proposed by various industry standard organizations and authorized by UCC/EAN organization. Each data type is identified with a numeric value, called Application Identifier (AI). Multiple AIs and data values can be concatenated together into one barcode, such as:

(01)19421123450011(15)991231(10)101234

The data above contains multiple AIs and values:

01 is the AI for SCC-14 case codes. The value is 19421123450011.

15 is the AI for Sell by Date. The value is 991231 which indicates that the Best Sell Date is December 31, 1999.

10 is the AI for Batch Number. The value can have variable length. Here the value is 101234.

The AI value determines the meaning and the length of the data part. Many of them encode a predefined length of data. For example, the SCC14 requires exact 14 digits and the Sell By Date requires exact 6 digits in YYMMDD format. The AI also defines how to make up to the required length. In most cases, leading zeros are inserted to the data.

When the data length can be derived from the AI, it is not necessary to add field separator (FNC1) in the barcode to separate two adjacent fields. However, if the first field has a variable data length, such a field separator is required. And in many applications it is often desirable to have a field separator between two fixed-length fields. The Code128 symbol character FNC1 is served as the field separator.

To understand each data field, the Monterey Barcode Creator requires you to enter the data in a special format. The AI must be enclosed with parentheses. From the AI, Monterey Barcode Creator knows whether a field has a fixed length or a variable length. For all variable-length fields, Monterey Barcode Creator inserts field separator unless it is located at the end of the symbol.

The Monterey Barcode Creator also performs data validation on the AI and the data, if the AI is known to the program.

If the AI is not listed in the table above, Monterey Barcode Creator can not know whether its data length is fixed or variable. Thus, the Monterey Barcode Creator treats the data as if its data length is variable and insert the field separator FNC1 when this field does not end the symbol.

For example, suppose that you set Message to (01) 19421123450011(99)123456(15)051210. The Monterey Barcode Creator understands that 01 AI requires fixed-length 14 digits data and AI 15 requires fixed-length 14 digits data. However, Monterey Barcode Creator does not understand the AI 99 and treats this field as if it has a variable length. The Monterey Barcode Creator inserts a field separator at the end of this field (before AI 15).

Assuming that AI 99 requires a fixed data length and you'd like to reduce the overall barcode size, you can tell Monterey Barcode Creator that the field has a fixed data length by appending a tilde character ~ at the end of the field. For example, you can assign the value below:

(01)94211234500122(99)123456~(15)051210

When the Monterey Barcode Creator sees the ~, it treats the current field as fixed-length.

On the other side, if a known AI has a fixed data length but you'd like to have a field separator at the end of the field, you can do so by adding an exclamation character at the end of field, such as:

(01)94211234500122!(99)123456(15)051210

It forces a field separator to appear after the SCC14 number even AI 01 has a fixed data length and the field separator is not required. Sometimes this field separator is desirable because it is easier for the application to parse the input.

See the table below for a comparision of results produced by different inputs. The[ GS] is the scanner output for FNC1 character.

Barcode	Data input/Scanner output
	(01)94211234500122(99)123456~(15)051210 01942112345001229912345615051210
	(01)94211234500122!(99)123456(15)051210 0194211234500122[ GS]99123456[ GS]15051210
	(01)94211234500122(99)123456(15)051210 019421123450012299123456[ GS]15051210

SCC-14 (AI=01) and SSCC-18 (AI=00) require the data to end with a check digit. When the property UccEanOptionalCheckDigit is TRUE, and Monterey Barcode Creator finds that the data length is exactly one less than the required length, it calculates the check digit and appends it at the end of the data. The check digit also appears in the human readable text. For example, the SCC-14 code (01)94211234500122 can be entered as (01)9421123450012.

To create the barcode correctly, you must enclose the AI with parentheses ( ). The Monterey Barcode Creator only accepts numeric AI values. It reports an error when encountering a non-numeric character in the AI part. If AI does not appear in the known list (see the table above), and you do not want the data treated as variable length, you should tell so by appending a tilde character at the end of the field.

Some times, it is desirable to have the data separated by spaces in the human readable text. For example, you may like to see the human readable text (8101)0 5432112000(21)123456 instead of (8101)0543211200(21)123456. You can create the desirable human readable text by entering the message exactly like the one you'd like the human readable to be. Monterey Barcode Creator ignores the spaces during the encoding, but preserves them in the human readable text, as the one below illustrates:

Monterey Barcode Creator performs the following validations during the encoding process:

If your application does not pass the validation, you can not use UCC/EAN-128 to encode the data. Nevertheless, since UCC/EAN-128 encoding is based on Code128 symbology, you can encode the data directly with Code128. Here are several hints you may consider when converting the EAN-128 data into a Code128 input:

For example, Code128 with message ~18101054321120021123456 produces the exact barcode as the one using UCC/EAN-128 with message (8101)0 54321 1200(21)123456.

Some non-standard applications do not encode the FNC1 in the starting message. When this is the case, remove ~1 at the beginning of the input.