Code 128 / GS1-128 Barcode FAQ & Tutorial

INDEX:

• Code 128 Barcode Symbology Overview
• Code 128 Standards
  • AIAG
  • ISBT-128
  • SSCC-18
  • USPS GS1-128 (EAN128)
  • USPS Container Barcode
  • USPS-L-3216 24 Digit Tray Label
  • GS1-128 Barcodes (EAN128 & UCC128)
    • Encoding the AI / FNC1 character
    • Examples of encoding GS1-128
    • Decoding AIs and FNC1 Codes
    • Symbol Size
    • MOD 10 Check Digits
• Printing Code 128 Barcodes
• Encoding Tabs and Return Functions in Code 128 Barcodes

  ------- Code 128 Products ------- Barcode Fonts .NET Windows Forms Control ActiveX Control ASP.NET Server Control ASP Server for IIS Barcode Label Software Crystal Reports Java Class, Applet & Servlet FileMaker Image Generator Microsoft Access Native JavaScript Online Generator Oracle Reports Reporting Services Windows Mobile XML Webservice Barcode Scanners Barcode Printers

• Reading and Scanning
• The Character Set
• Manual Check Digit Character Calculation Examples
• If a scanner is needed, IDAutomation also provides barcode scanner kits.

The Code 128 barcode is a high-density linear symbology that encodes text, numbers, numerous functions and the entire 128 ASCII character set (from ASCII 0 to ASCII 128.) It is commonly used for several implementations; and is also referred to as ISBT-128, GS1-128, UCC-128, EAN-128 and USS Code 128.

Code 128 contains 106 different printed barcode patterns. Each printed barcode may have one of three different meanings depending upon which of the character sets are being used, with the availability of three different Code 128 start characters to program the initial character set. Functions are also provided in the barcode symbology to switch between character sets and encode Application Identifiers. The Code 128 barcode may be complex to use because of the different character sets, which is the primary reason IDAutomation provides the Code 128 auto function, "Code128( )", in several of the Font Tools, Components and Applications.

The complete Code 128 barcode consists of a start character, data digits, a modulo 103 check digit and a stop character.

Start Character	Data Digits	Check Character	Stop Character
Ì	CODE-128	O	Î

The above Code 128 barcode symbol was created with the IDAutomation Barcode Image Generator.

Several standards exist that dictate how Code 128 barcodes should be generated for certain implementations; a few of these include:

• GS1-128 (previously known as UCC-128 and EAN-128) is defined by GS1 and used to create several types of barcode symbols that include Application Identifiers. Application Identifiers (AIs) define the purpose of the data in the symbol and how it is to be used.
• ISBT-128 is specifically designed for printing blood product barcode labels. It was developed by the International Society of Blood Transfusion (ISBT) and the Working Party on Automation and Data Processing (WPADP).
• USS Code 128 (Uniform Symbology Specification Code 128) is the published specification for the Code 128 barcode.
• ISS Code 128 (International Symbology Specification Code 128) is the USS Code 128 barcode symbology with a new feature that allows the encoding of extended ASCII characters for non-English languages.
• The Global Trade Item Number (GTIN), or previously known as EAN14, is the product identification structure in the GS1 (EAN/UCC) system. The GTIN is a 14 digit fixed length numeric string, including the indicator digit (or logistic variant), the EAN/UCC company prefix, item reference and check digit. When using the GS1-128 barcode symbology, the data will need to be appended with the Fnc1 character and an Application Identifier of 01. The GTIN should always be stored in databases as a 14-digit number. When the GTIN is represented in UPC-A, UPC-E, GTIN-8 and GTIN-13, as 8, 12, or 13 digits, it should be stored as a 14-digit number by appending zeros to the beginning of the data.
• SSCC-18 is a serialized shipping label specification.

Several Barcode Integration Guides are available that suggest various barcode printing options. These integration options should be examined to determine whether to use barcode components, applications or fonts for the printing of barcodes. A few of the Barcode Integration Guides offered include the following:

• Access
• Crystal Reports
• Excel
• FileMaker
• Open Office & Star Office
• Oracle Reports
• Reporting Services
• C++
• C# .NET
• Visual Basic 6 and VB.NET
• Web Barcode Implementation

Featured Product:

The IDAutomation Universal Barcode Font Advantage Package is a unique product that excels at generating barcode 128 on multiple operating systems and locales, including Double Byte versions of Windows. This package overcomes the obstacles that sometimes occur when printing Code 128 as a barcode font outside of the Unites States.

The most common method of reading code 128 barcodes is with a linear barcode scanner. Most of the barcode scanners recommended by IDAutomation perform keyboard emulation and receive power from the USB port, so no external power supply is required. When a barcode is scanned using keyboard emulation, the data scanned appears at the cursor as if it had been typed from the keyboard.

Most barcode scanners have the ability to read Code 128 barcodes by default, such as the IDAutomation USB Barcode Scanner. This scanner dependably reads the IDAutomation Code 128 Barcode Font and Universal Barcode Font when printed as small as 6 points, which is an X dimension of 4 mils.

The Code 128 barcode symbology is used to create GS1-128 (formerly UCC128 or EAN128) barcodes such as the GS1-128 symbols and data structure for SSCC18 and SCC14. Every GS1-128 barcode begins with a Start C character followed by a (FNC1) "Function Code One" and an Application Identifier (AI) number. The AI defines the specific purpose for the data encoded. When encoding AIs for use in POS systems, IDAutomation recommends using the DataBar Expanded barcode type. Below are some of the requirements for GS1-128 and how to implement them in IDAutomation products.

• Symbol Size:
  According to GS1-128 specifications, the height of the barcode should be 15% of the length or 0.50 inch (1.3 CM), whichever is greater. The X dimension may range from 10 mils (.025 cm) to 40 mils (.1 cm). When the X dimension used is between 10 and 16 mils, the symbol should be 0.50" tall. When the X dimension used is between 16 and 40 mils, the symbol should be 1.25" tall. The X dimension of 10 mils (0.10") is recommended for use with most hand-held scanners. The IDAutomation Code 128 Barcode Font IDAutomationC128M and Universal Barcode Font IDAutomation Uni M are specifically designed for this purpose. They are exactly 0.50" tall with an X dimension of 10 mils when printed at 12 points.
• GS1 FNC1 and the Application Identifier (AI):
  When a barcode begins with the FNC1, the digits following it represent the Application Identifier (AI), which defines data fields in the symbol. The AI is represented with parentheses around it as in the example to the right, which is a barcode encoding an AI of 8100 with data of 712345 and an AI of 21 with the data of 12345678. FNC1 characters and AIs may be easily encoded in IDAutomation products according to the following:
  • Parentheses Method: IDAutomation products with build dates May 2009 or later include functionality that allows users to easily add application identifiers by adding the parentheses where needed when ApplyTilde is enabled in Code 128. To encode (8100)712345(21)12345678 with this method, (8100)712345(21)12345678 would be used. This may be tested with the Free Online Barcode Generator or from the bcgen.com command line, for example:
    http://bcgen.com/demo/linear-dbgs.aspx?D=(8100)712345(21)12345678&PT=T
  • Tilde Method: All IDAutomation products support the inclusion of the AI as a tilde command when ApplyTilde is enabled in Code 128. When using this method, the parentheses are not included in the data encoded; instead the tilde character plus 3 digits are used to represent the AI. Use the following extended ASCII character as the FNC1 for the correct number of digits in the AI:
    ~212 = 2 digit AI             ~213 = 3 digit AI           ~214 = 4 digit AI
    ~215 = 5 digit AI             ~216 = 6 digit AI           ~217 = 7 digit AI
    Example: to encode (8100)712345(21)12345678 with the Tilde Method, ~2148100712345~2122112345678 would be used. Additional examples are included in Fig 1.
  • Direct ASCII Method: This method is somewhat easier to implement, however, there are compatibility limitations. Several IDAutomation products support the inclusion of the AI with ASCII 202 (the Ê character) in Code 128 auto. When using this method, ApplyTilde does not have to be enabled and the parentheses are not included in the data encoded. To make the human-readable digits accurate, use the associated ASCII character listed below as the FNC1 for the correct number of digits in the AI.
    NOTE: The following are character examples from the 1250 ISO Latin 1 character set used in Europe & the USA. When using the MAC or systems outside of the USA, the appropriate character must be used that represents the proper ASCII location. When in doubt, use the Tilde Method.
    ASCII212: Ô = 2 digits             ASCII213: Õ = 3 digits       ASCII214: Ö = 4 digits
    ASCII215: × = 5 digits              ASCII216: Ø = 6 digits       ASCII217: Ù = 7 digits
    Example: to encode (8100)712345(21)12345678 with the ASCII Method, Ê8100712345Ê2112345678 or Ö8100712345Ô2112345678 would be used.
    ASCII Method Compatibility Limitations: This method is not compatible with the following:
    • Web based products such as the Online Barcode Generator, Barcode Server for IIS, Web Server Control and Java Servlet.
    • Systems that are not operating in the 1250 ISO Latin 1 character set used in Europe & the USA. When using systems outside of the USA, the appropriate character must be used that represents the proper ASCII location.
    • MAC systems and FileMaker products; because they use the MAC Roman character set.
  • Symbol Size Reduction: The methods represented above insert FNC1 codes into the symbol. If symbol size needs to be minimized, multiple AIs may be included in a single barcode without encoding additional FNC1 codes, provided that variable length AIs are included last. The parentheses may not correctly appear in the text interpretation of the symbol when using this method of encoding, however they may be easily included by inserting a custom text field near the symbol if required.
• FNC2:
  The FNC2 character may be inserted as ASCII 197 in IDAutomation barcode products, for example: ~19780-128-4991 encodes [FNC2]80-128-4991. The IDAutomation SC5USB Barcode Scanner may be programmed to hold the barcode starting with the FNC2 in memory and only transmit data after scanning a second barcode, which allows a continuous text string to be encoded in two barcodes.
• MOD 10 Check Digits:
  A GS1 MOD 10 check digit is often required when implementing GS1-128 barcodes for various specifications; the AI is usually not included in the MOD 10 calculation. If a MOD 10 check digit is needed, it may be either pre-calculated or calculated in the barcode component at the time it is created. To enable IDAutomation barcode products to calculate the MOD 10 when the barcode is created, the ApplyTilde property must be enabled and the format ~m?? must be used where ?? is a 2 digit number representing the number of characters preceding the tilde on which to base the Mod 10 calculation. For example, entering the data of ~2140000801234999999999~m17 creates a barcode encoding the FNC1 character followed by an AI of (00) and the number of 008012349999999997. This MOD 10 calculation may be checked online with the IDAutomation Online Barcode Font Encoder by entering the number of 00801234999999999 in the "Data To Encode" field and choosing the "MOD 10" option.

Fig. 1: Examples of Encoding GS1-128 (UCC/EAN-128) with IDAutomation Products

NOTE: When encoding AIs for use in POS systems, IDAutomation recommends using the DataBar Expanded barcode type.

Additional Examples:

* Many barcode scanners do not decode FNC1 codes. However, when the "format" option of the IDAutomation SC5USB Barcode Scanner is set to "UCC/EAN-128," FNC1 codes are decoded as ]C1 for the first FNC1 and ASCII 29 (The <GS> character) for additional FNC1 codes as required by GS1. IDAutomation's Barcode Scanner ASCII String Decoder may be used to view the <GS> character.

GS1 renamed several barcode standards built on Code 128 such as EAN-128 and UCC-128 to GS1-128. The name change does not change the barcode standards; therefore, documentation referring to EAN-128 and UCC-128 is the same as GS1-128. GS1 also recently renamed the RSS Symbology to GS1 DataBar to avoid confusion with RSS feed technology.

Most scanners with built-in decoders do not decode FNC1 codes in GS1-128 (UCC/EAN-128) barcodes. However, when the "format" option of the IDAutomation SC5USB Barcode Scanner is set to "UCC/EAN-128," the scanner decodes FNC1 AI codes according to the UCC/EAN Application Identifier Standard. According to this standard, the first FNC1 should be translated to the three text characters of ]C1, and next FNC1 codes should be translated to a field separator ASCII code 29 (The <GS> character) as demonstrated in Fig. 2.

Fig. 2: Decoding FNC-1 Codes with the IDAutomation SC5 USB Barcode Scanner

String used to create the barcode using IDAutomation products: Ê8100712345Ê2112345678
Barcode Created:		The image to the left may be easily created using the Free Online Barcode Creator.
Decoded result from the IDAutomation SC5 USB Scanner:
]C1	8100712345	<GS>*	2112345678

* The <GS> character is a group separator function, which is ASCII value 29. This character cannot be viewed or printed and therefore it may not appear to be present, unless an application is used such as IDAutomation's Barcode Scanner ASCII String Decoder. If the SC5 USB Barcode Scanner is being used, the GS character can be reassigned to any ASCII character by changing the "field separator code" referred to in the manual. For example, this may be changed to the "|" character to make troubleshooting easier. After making that change, the scanner would decode the symbol in Fig. 2 as follows:
]C18100712345|2112345678. To program this change with the SC5 USB Barcode Scanner, perform the following:

1. On the Code 128 programming page, scan Program.
2. Scan Field Separator Code.
3. Field separator codes are programmed into the scanner as a hexadecimal BASE-16 number. The pipe character "|" is ASCII 7C. From the Manual's flip out page, scan 7, scan C and scan Finish.
4. On the Code 128 page, scan Exit.

The United States Postal Service (USPS) uses Code 128 barcodes for many special services such as delivery confirmation; which is formatted as follows:

1. Start C character
2. FNC1 character
3. 2 digit AI (Application Identifier, which is usually 91)
4. 2 digit service code
5. 9 digit customer ID
6. 8 digit sequential package ID
7. Mod 10 check digit
8. Mod 103 symbology check digit
9. Stop character

The start, stop and mod 103 check digits are automatically added in all of IDAutomation barcode products. To create the required Code128 barcode, use Code 128 Auto with ApplyTilde enabled and add in the appropriate ASCII 202 and AI’s (as documented in the GS1-128 section of this FAQ). A MOD 10 Check Digit is also required at the end of the data encoded. This may be easily generated in IDAutomation products with the ~m command as demonstrated in Fig 3.

When printed at 16 points, the IDAutomationC128L font will produce the exact dimensions for GS1-128 (UCC/EAN Code128) required by the USPS special services, which is a height of .75" and an X dimension of .013". For more information, refer to the USPS specifications. More information about formatting GS1-128 barcodes with IDAutomation products is provided in the GS1-128 section of this FAQ.

Fig. 3: Example of Encoding USPS Barcodes

In the example below, the ASCII 202 character (Ê) may be used in place of ~??? for products that do not support ApplyTilde.

* USPS Characters Below the Barcode
The human-readable characters below the barcode may be easily generated with IDAutomation products by utilizing the SpliceText option with the Sans Serif Bold or equivalent type font.

In the event the human-readable characters below the barcode need to be created from code, the Sans Serif Bold font should be used and spaces should be inserted between every 4 digits. The following Visual Basic VBA code accomplishes this purpose:
Mid(DataToEncode, 1, 4) & " " & Mid(DataToEncode, 5, 4) & " " & Mid(DataToEncode, 9, 4) & " " & Mid(DataToEncode, 13, 4) & " " & Mid(DataToEncode, 17, 4) & " " & Mid(DataToEncode, 21, 2)

Several other combinations are possible. For more information, refer to the USPS barcode specifications. The USPS has also standardized a newer 4-state barcode type defined as the Intelligent Mail Barcode, which encodes delivery and tracking information in a single symbol.

The three character sets listed below are for the Code 128 barcode. In the columns A, B and C, are listed the character or function the barcode scanner will read for the associated symbol. The "ASCII" and "Unicode" columns designate the location where the barcode symbol for the character resides. The column "Char" lists the character that resides at the ASCII location, which is used to print the corresponding symbol. The ASCII location for the space character, stop character and character values 94-105 are applicable only to IDAutomation products including the Code 128 Barcode Fonts. The ISO specification for Code 128 does not specify the location of ASCII and Unicode values for these symbols.

* It is necessary to print the Code 128 space character from ASCII 194 instead of ASCII 32 because some applications do not print a symbol instead of a space character. The ASCII location for the space character, stop character and character values 94-105 are applicable only to IDAutomation barcode products including the Barcode 128 Fonts. Additionally, the characters listed for values 00 and 94-105 are from the Latin-1 codepage. When the Latin-1 codepage is not being used, or when using a Macintosh, it is suggested to use the Universal Barcode Font Advantage™, which creates Code 128 barcodes as a font in any codepage and operating system.

IDAutomation provides several font tools, plug-ins and source code samples that are free to use with IDAutomation barcode fonts, which will automatically format the start, stop and check characters to the barcode fonts. Therefore, the manual calculations described here are rarely necessary.

The following examples create a barcode with the IDAutomation Code 128 Barcode Fonts in the Latin-1 codepage, which is the default setting in the USA. When the Latin-1 codepage is not being used, or when using a Macintosh, it is suggested to use the Universal Barcode Font Advantage™, which creates the Code 128 barcode as a font in any codepage and operating system.

The following process is used to determine the value of the check character:

1. Reference the character set table to obtain the value of the start character and all data characters.
2. Assign a weight to each data character (not the start character, just the data characters.) The weighting starts at 1 and increases by one for each data character.
3. Multiply the character values by their weights for the data characters.
4. Add these together including the start character, divide by 103 and obtain the remainder.
5. Use the character set table to locate the character that has the value of the remainder, use this as the check character.

Calculation Example for Character Set A or B:

The following table is an example of how to obtain the check character for the data "biz" using Code 128 character set B.

1. Calculate the Total: 104 + (66*1) + (73*2) + (90*3) = 586
2. Calculate the Checksum: 586 divided by 103 = 5 remainder of 71. Therefore, the check digit equals a value of 71. The character to print for the value of 71 is "g" or ASCII 103.

To print the data "biz" as a barcode, the text of ÌbizgÎ is combined with the Code 128 Barcode Fonts.

Calculation Example for Character Set C:

The following table is an example of how to obtain the check character for the number "667390" using character set C.

1. Separate the numbers into pairs and choose the appropriate character from the character set table that represents the number pair.
2. Calculate the Total: 105 + (66*1) + (73*2) + (90*3) = 587
3. Calculate the Checksum: 587 divided by 103 = 5 remainder of 72. Therefore, the check digit equals a value of 72. The character to print for the value of 72 is ASCII 104.

To print the data "667390" as a barcode, the text of ÍbizhÎ is combined with the Code 128 Barcode Fonts.

Calculation Example for Multiple Character Sets:

The following table is an example of how to encode the data "biz" using Code 128 character set B with a switch to character set A for a carriage return function.

1. Calculate the Total: 104 + (66*1) + (73*2) + (90*3) + (101*4) + (77*5) = 1375
2. Calculate the Checksum: 1375 divided by 103 = 13 remainder of 36. The check digit equals a value of 36. The character to print for the value of 36 is "D" or ASCII 68.

Encoding functions such as returns and tabs may make data entry tasks easier. Functions are easily encoded with the appropriate ASCII function code. Normally, these characters are not visible unless an application is used such as IDAutomation's Barcode Scanner ASCII String Decoder, which displays these hidden functions as tags.

Automatic Encoding with Code 128 Auto:

Functions may be directly encoded in IDAutomation products by enabling "ApplyTilde" in Code128 Auto, and using the format ~??? to specify the ASCII code of the function. For example, Code~009Bar~013 will encode
Code[TAB]Bar[RETURN].

When ApplyTilde is not available, the programming code syntax for the ASCII function code may be used in the formula for the DataToEncode. For example, the following formulas combine two fields in a single barcode with a tab function separator:
Crystal Reports: IDAutomation_Code128 ({Table1.DataField1} & Chr(9) & {Table1.C128})
Microsoft Access: =( [Table1.Field1] & Chr(9) & [Table1.Field2] )
VB .NET: DataToEncode =DataString1 & Chr(9) & DataString2
Java: DataToEncode =DataString1 + (char)9 + DataString2;

Encoding Functions with Set A:

Caution should be used in character set A because any lowercase letter will create a function according to the chart. Use the letter "i" for a tab and "m" for a return. Other functions may be determined by looking up the column for Code A in the character set chart. For example, the following character string in character set A encodes the data "JOHN[tab]SMITH[tab]128-288-6794[return]":
JOHNiSMITHi128-288-6794m

If assistance is needed, please contact IDAutomation.

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