Interleaved 2 of 5 | ITF-14 Barcode FAQ & Tutorial

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Interleaved 2 of 5 Barcode Overview

Interleaved 2 of 5 ITF fonts with Bearer BarsInterleaved 2 of 5 (ITF) is a numeric only barcode used to encode pairs of numbers into a self-checking, high-density barcode format. In this symbology, every two digits are interleaved with each other to create a single symbol. If a number string containing an odd number of digits needs to be encoded, a leading zero must be added to produce an even number of digits in the Interleaved 2 of 5 barcode. In many cases, the Code 128 barcode offers an advantage over the ITF barcode because it encodes even and odd numbers of digits, as well as letters and symbols, with nearly equal density.

The symbology of the character set consists of barcode symbols representing numeric characters 00 to 99, the space character and start/stop characters. The complete printed barcode consists of a leading quiet zone, a start pattern, interleaved symbols representing data, an optional MOD 10 check character, a stop pattern, a trailing quiet zone and an optional bearer bar pattern surrounding the entire symbol.

The IDAutomation Interleaved 2 of 5 Barcode Font Package provides 4 different font formats (as shown in the graphic to the right) to meet various requirements. These formats are, in the order they appear:

  • Standard
  • Standard Human Readable
  • Bearer Bar
  • Bearer Bar Human Readable

The bearer bar versions are provided to meet certain specifications such GS1 ITF-14. Some of these specifications state that only horizontal bearer bars along the top and bottom of the barcode symbol are necessary, the bearer bar versions provided in this package completely surround the barcode which meet or exceed any bearer bar requirement.

USS Interleaved 2 of 5 (Uniform Symbology Specification Interleaved 2 of 5) is the published specification for Interleaved 2 of 5. All IDAutomation products support the published specification. Several standards exist that dictate how ITF barcodes should be generated for certain implementations; a few of these include ITF-14, EAN-14, SCC-14, GTIN, VCA OPC and DUN14.

ITF-14

ITF-14 is the GS1 System’s only use of Interleaved 2 of 5 and it is only used to encode the GTIN as a 14 digit number. It is commonly used on shipping boxes and containers.

Bar Height:
The minimum recommended bar height for an ITF-14 Barcode is 32mm (1.25″) when used in General Distribution Scanning environments (automated scanning). For all other scanning applications, the height should be as high as possible. In no case shall the bar height be less than 13mm (.5″). While 13mm (.5″) is the minimum height for barcodes not being scanned in an automated scanning environment, every effort should be made to increase the bar height to 32mm (1.25″) as possible.

Bar Width (X Dimension):
The X Dimension is the width of the smallest bar in the symbol. In automated scanning environments, the X Dimension should be 0.495mm – 1.02mm (20 to 40mils). For all other scanning applications, the acceptable range is 0.250mm to 0.495mm (10-20mils).

Bar Width Ratio (N Dimension):
Bar width ratio (also known as the Narrow to Wide ratio or the N Dimension) is the difference of bar widths between the wide bars and the narrow bars in an ITF-14 Barcode. The acceptable range is 2.25:1 to 3:1. The IDAutomation Interleaved 2 of 5 Barcode Fonts have an N dimension of 2.75:1.

When using the IDAutomation Interleaved 2 of 5 Barcode Fonts, the following chart provides the recommended font name and size to use.

 EnvironmentFont NamePoint SizeX DimensionHeight
 Automated ScanningIDAutomationI25XL28.495mm (20 mils)38mm (1.5″)
 General ScanningIDAutomationI25L14.25mm (10 mils)14mm (.55″)

Bearer Bar and Checksum Options

Barcode example created with bearer bar fonts.The purpose of “Bearer Bars” and the checksum is to reduce the possibility of misreads or short scans that may occur when a skewed scanning beam enters or exits the barcode symbol through its top or bottom edge. Bearer Bars should be a constant minimum thickness of twice the width of the narrow bar, placed directly against the top and bottom of the symbol bars. The bearer bars should completely surround the symbol, including the Quiet Zones, which are a minimum of 10 times the X dimension, which is the width of the narrow bar of the barcode. Many mandates for i2of5 require Bearer Bars and a MOD 10 Checksum. Some specifications state that only horizontal bearer bars along the top and bottom are necessary, however, it is better to use bearer bars that completely surround the barcode because it meets or exceeds any bearer bar requirement.

IDAutomation provides several sets of ITF bearer bar fonts (which completely surround the barcode) in the Interleaved 2 of 5 Barcode Fonts. In addition, IDAutomation provides many Font Encoders, Components and Applications that easily support Bearer Bars and checksum calculations.

Printing ITF Barcodes

Several Barcode Integration Guides are available that suggest one or more barcode printing options. These integration options should be examined to determine whether to use barcode components, applications or barcode fonts for the printing of Interleaved 2 of 5 barcodes. A few of the Barcode Integration Guides offered include the following:

Featured Product:

The IDAutomation Universal Barcode Font is a unique product that excels at generating ITF barcodes on multiple operating systems and locales, including Double Byte versions of Windows. This product overcomes the obstacles that sometimes occur when printing the Interleaved 2of5 barcode font outside of the USA. It also provides three different narrow to wide ratios: 2, 2.5 and 3.

Reading & Scanning

The most common method of reading barcodes is with a barcode scanner. Most of the barcode scanners recommended by IDAutomation perform keyboard emulation and receive power from the USB port, so that 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 in from the keyboard.

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

The ITF Barcode Font Character Set

The character set referenced here is unique to the IDAutomation Interleaved 2 of 5 Barcode Font. IDAutomation provides several font encoders, macros and source code samples that may be used royalty-free with this font to automatically format the data being encoded to the barcode fonts. Therefore, references to this character set may not be necessary.

To manually create a barcode encoding the number 772233 with the chart below, use the following process:

  1. Include the START character: Ë
  2. Include the data characters from the char columns that represent 2 numbers from the ITF code column. For example, the numbers of 77 22 33 is represented in characters: n7B
  3. Include the STOP character: Ì
  4. Combine the resulting text string with the barcode font: Ën7BÌ

The “ITF Code” column lists the character that the scanner will read for the associated symbol. The columns ASCII, Char and Unicode designate the location in either ASCII or Unicode where the barcode symbol for the character resides in the barcode fonts. When the Latin-1 codepage is not being used, it is suggested to use the Universal Barcode Font Advantage, which creates the ITF barcode as a font in any codepage and operating system in the same way.

ITF Barcode Character Set Chart

 ITF CodeASCII *Unicode *Char  ITF CodeASCII *Unicode *Char
 na00320020space5100840054T
 0000330021!5200850055U
 01003400225300860056V
 0200350023#5400870057W
 0300360024$5500880058X
 0400370025%5600890059Y
 0500380026&570090005AZ
 0600390027580091005B[
 0700400028(590092005C\
 0800410029)600093005D]
 090042002A*610094005E^
 100043002B+620095005F_
 110044002C,6300960060`
 120045002D6400970061a
 130046002E.6500980062b
 140047002F/6600990063c
 150048003006701000064d
 160049003116801010065e
 170050003226901020066f
 180051003337001030067g
 190052003447101040068h
 200053003557201050069i
 21005400366730106006Aj
 22005500377740107006Bk
 23005600388750108006Cl
 24005700399760109006Dm
 250058003A:770110006En
 260059003B;780111006Fo
 270060003C<7901120070p
 280061003D=8001130071q
 290062003E>8101140072r
 300063003F?8201150073s
 3100640040@8301160074t
 3200650041A8401170075u
 3300660042B8501180076v
 3400670043C8601190077w
 3500680044D8701200078x
 3600690045E8801210079y
 3700700046F890122007Az
 3800710047G900123007B{
 3900720048H910124007C|
 4000730049I920125007D}
 410074004AJ930126007E~
 420075004BK94019700C5Å
 430076004CL95019800C6Æ
 440077004DM96019900C7Ç
 450078004EN97020000C8È
 460079004FO98020100C9É
 4700800050P99020200CAÊ
 4800810051QSTART020300CBË
 4900820052RSTOP020400CCÌ
 5000830053S

* Some ASCII and Unicode values in this chart are unique to IDAutomation Interleaved 2 of 5 Barcode Fonts. The specification for Interleaved 2of5 does not specify the actual location of ASCII and Unicode values for the symbols in a font.

MOD 10 Check Character Calculation Examples

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

Generating Standard MOD 10 Check Digits:

Since Interleaved 2 of 5 requires an even number of digits to “interleave” numbers, the data encoded must be an odd number of digits when using a check character, thus resulting in the required even number of digits.

The standard method of obtaining the check character (referred to as USS Interleaved 2 of 5 MOD 10) is obtained by performing the following calculation:

  1. Add up the odd numbers in the code.
  2. Multiply the sum of the odd numbers in the code by 3.
  3. Add up the even numbers.
  4. Determine the number that when added to the sum, will produce a multiple of 10.

For example, the check digit for 123456789 is 5 because (3*(1+3+5+7+9))+(2+4+6+8) = 95. The next multiple of 10 after 95 is 100, therefore the check digit would be 5, because 95 + 5 =100.

Identcode & Leitcode Checksum Calculations:

The calculation for Identcode and Leitcode applications is similar to USS Interleaved 2 of 5 MOD 10, except that even numbers are multiplied by 9 and odd numbers by 4. For example, the check digit for 12345678901 would be “6” because (4*(1+3+5+7+9+1))+(9*(2+4+6+8+0)=284 and 284 + 6 = 290.

The following examples create a barcode with IDAutomation Interleaved 2 of 5 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 Mac, it is suggested to use the Universal Barcode Font, which creates ITF and many other barcode types from a single font in any codepage and operating system.