A basic idiots guide to Barcodes provided by a company who have been supplying barcode labels for 25+ years and as a way to help others when they have to order bar code labels and do not know the jargon being used.
Mr Woodland and Silver, who were teaching at Drexel University in Philadelphia, b
work that led to the bar code after the head of a supermarket chain asked for help
a better way to keep track of inventory. A former Boy Scout, Woodland wondered
Code could be used to track inventory, and began drawing lines of different thickn
sand during a visit to Miami in 1948. The code that eventually emerged is now kno
Universal Product Code, and Woodland won the National Medal of Technology in
LITTLE BIT OF HISTORY
Joseph Norman Woodland
What is a Barcode?
A barcode is an optical machine readable
representation of data, which shows data about the
object to which it attaches.
Originally barcodes represented data by varying the
widths and spacings of parallel lines, and therefore
were referred to as linear or one-dimensional (1D).
Later they evolved into rectangles, dots,hexagons and
other geometric patterns in two dimensions (2D).
So how does it work ?
A barcode reader uses a photo sensor to convert the barcode into an electrical signal as it moves across a
barcode. The scanner then measures the relative widths of the bars and spaces, translates the different
patterns back into regular characters, and sends them on to a computer or portable terminal.
Every barcode begins with a special start character and ends with a special stop character. These codes
help the reader detect the barcode and figure out whether it is being scanned forward or backward.
Some barcodes may include a checksum
character just before the stop character.
A checksum is calculated when the barcode is
printed using the characters in the barcode.
The reader performs the same calculation and
compares its answer to the checksum it reads at
the end of the barcode. If the two don't match,
the reader assumes that something is wrong,
throws out the data, and tries again.
A Barcode is simply machine readable language. The barcode is a set of lines and spaces that represents a
set of characters. These characters can be alphabetic or numeric depending on the type of barcode used.
Below are some individual letters and characters.
Elements of the Barcode
X dimension: The width of the narrowest bar or space is referred to as the X dimension, usually given in
mils (thousandths of an inch). The X dimension dictates the width of all other bars and spaces, and
ultimately the length of the bar code.
Left & Right Light Margins (Quiet Zones): These are the areas before and after a code that must be left
clear to enable the scanner to correctly read the barcode, it has a direct relationship to the “X dimension”,
the wider the X dimension the wider the left/right light margin requirement.
Barcode Symbology Density: This is the rate of information that can be stored in the barcodes, a Code
128 barcode has a higher symbology density than a Code39 or Codabar barcode.
Human Readable: The data represented
by the bars and spaces printed as text for
people to read.
ALWAYS - Remember that the data
contained in the eye readable may not
reflect the data contained with the
barcode itself – ALWAYS SCAN TO
CHECK – NEVER ASSUME!!!!!!
Barcode Ratio: This is the ratio of wide to
narrow elements and helps to configure the
width of the final code, the bigger the ratio the
wider the final barcode. – NEVER AMEND
THE RATIO WITHIN SOFTWARE – THIS
CAUSES ERROR READS.
A barcode that encodes data only in one dimension.
Data is encoded in the widths of the bars and spaces and no data is encoded in the lengths of the bars.
The EAN or UPC barcode symbology found on many retail products is a common linear barcode that you
may be familiar with.
The need for ever increasing amounts of information in smaller spaces has lead to more compact and
higher data density symbologies found in two-dimensional or stacked barcodes.
A two-dimensional symbology is either:
”matrixed “ as in the data matrix code
"stacked” as in the PDF417 code.
Each type allows more information to be stored in a smaller amount of space.
EAN 13 & EAN 8
European Article Numbering international retail product code
EAN-13 or EAN-8 are two different versions of EAN bar codes, which can encode 13 and 8 digit numbers.
The EAN-8 code was introduced for use on small packages where an EAN-13 barcode would be too large.
All other countries aside from the United States utilize the EAN bar code for identification on retail goods.
USA use the UPC code for the same purposes, but this is only 12 digits long.
A General purpose code in very wide use world-wide.
The Code39 character set includes the digits 0-9, the letters A-Z (upper case only), and the following
symbols: space, minus (-), plus (+), period (.), dollar sign ($), slash (/), and percent (%).
A special start/stop character is placed at the beginning and end of each barcode.
(also known as "USS Code 39", "Code 3/9", "Code 3 of 9", "USD-3", "Alpha39", "Type 39", "Code 93”)
The code itself does not carry a check digit like the the Code 128 barcode and can often be identified
by an asterix at the start and end of the eye readable.
The barcode may be of any length, although more than 25 characters really begins to push the bounds.
It has a lower character density than the Code128 making it rather a wide code in comparison.
This code is steadily being replaced in many of it uses by the Code 128 barcode which has better
capabilities and a higher character density.
Very capable code, excellent density, high reliability; in very wide use world-wide
The Code128 provides excellent density for all-numeric data and good density for alphanumeric data.
It is often selected over Code 39 in new applications because of its symbology density and because it offers a
much larger selection of characters.
The Code 128 character set includes the digits 0-9, the letters A-Z (upper and lower case), and all standard
ASCII symbols and control codes. The codes are divided into three subsets A, B, and C. There are three
separate start codes to indicate which subset will be used; in addition, each subset includes control
characters to switch to another subset in the middle of a barcode. Subset A includes the standard ASCII
symbols, digits, upper case letters, and control codes. Subset B includes standard ASCII symbols, digits,
upper and lower case letters. Subset C compresses two numeric digits into each character, providing
A Code 128 barcode will have six sections:
Quiet Zone - Start Character - Encoded Data - Check Character - Stop Character - Quiet Zone
It has a medium to high character density making it widely used within the NHS, Records
Management, and Asset tracking markets.
This code is the most commonly used by AC Labels and is used by many of our customers that once used
Interleaved 2 of 5
Compact numeric code, widely used in industry, air cargo
The Interleaved 2 of 5 is a code that ONLY encodes the ten digits 0 through 9.
The name Interleaved 2 of 5 is derived from the method used to encode two characters.
The "Interleaved" part of the name comes from the fact that a digit is encoded in the bars and the next digit
is encoded in the spaces. The encoded digits are merged together or "Interleaved”.
The Interleaved 2 of 5 code can only carry numbers and due to its construction on interleaving it
can only carry an even number of digits.
Older code often used in library systems, sometimes in blood banks
The Codabar can encode the digits 0 through 9, six symbols (-:.$/+), and
the start/stop characters A, B, C, D.
The start/stop characters must be used in pairs and may not appear
elsewhere in the barcode. Codabar is used in libraries, blood banks, the
overnight package delivery industry, and a variety of other information
processing applications. There is no checksum defined as part of the
Codabar standard, but some industries (libraries, for example) have adopted
their own checksum standards.
This Code can only be used to carry Numeric data and a few special
characters, and can only be used in conjunction with smaller Modulus
algorithms where the check digits can only be a numeric value of 0-9.
This code is slowly being used less and less but is still prevalent within the
NHS blood bank and haematology department labelling.
Excellent for encoding large amounts of data
The PDF417 is a two-dimensional barcode which can store up to about 1,800 printable ASCII characters
or 1,100 binary characters per symbol.
Every codeword contains four bars and four spaces (where the 4 in the name comes from). The total
width of a codeword is 17 times the width of the narrowest allowed vertical bar (the X dimension). This is
where the 17 in the name comes from
The symbol is rectangular; the shape of the symbol can be adjusted to some extent by setting the width
and allowing the height to grow with the data.
The capacity of PDF-417 can be helpful in applications where the data must travel with the labelled item,
where a host database is not always available for quick look-up.
Uses: Hazardous materials labeling, storing technical specifications and calibration data on electronic
instruments; encoding fingerprints and photographs on the backs of US drivers' licenses.
Please Note: PDF-417 symbols require a 2-D scanner; or a standard CCD (Charge Coupled Device) or
laser scanner and will also require special decoding software, a normal wand scanner will not work.
2D Barcode / Data Matrix
Dot-Matrix / Data Matrix
Can hold large amounts of data, especially suited for making
very small codes
The 2D Barcode / Data Matrix is a two-dimensional barcode which can store from 1 to about 2,000
characters. The symbol is square and can range from 0.001 inch per side up to 14 inches per side.
Uses: Data Matrix is being used to encode product and serial number information on electrical rating
plates; to mark surgical instruments in Japan; to identify lenses, circuit boards, and other items during
manufacturing. The main sectors for use are for track and trace, anti-counterfeit, and banking solutions
Dot Matrix symbols require a
2-D scanner; they cannot be
read using an ordinary linear
barcode scanner. A number
of scanners are on the
market using both laser and
CCD (Charge Coupled
(abbreviated from Quick Response Code) is the trademark for a
type of matrix barcode first designed for the automotive industry in
Can hold large amounts of data, especially suited for making
very small codes
Recently, the QR Code system has become popular outside the automotive industry due to its fast
readability and greater storage capacity compared to standard linear codes.
The code consists of black modules (square dots) arranged in a square grid on a white background.
Uses: Particularly used in promotional marketing and website linkages.
In June 2011, the Royal Dutch Mint issued the world's first official coin with a QR code to celebrate the
centennial of its current building and premises. The coin was able to be scanned by a smartphone and
link to a special website with contents about the historical event and design of the coin.
This was the first time a QR code was used on currency.
A check digit is simply the result of a calculation made from the data within in a
ADSR7 / Mod 10 / Mod11 / Mod16 / Mod23 / Mod26
Standard Modulus Check Digits
1. The checksum is a Modulo 10 calculation:
2. Add the values of the digits in the odd-numbered positions: 1, 3, 5, 7 etc.
3. Multiply this result by 3.
4. Add the values of the digits in the even-numbered positions: 1, 4, 6, etc.
Sum the results
5. The check character is the smallest number which, when added to the result in
step 4, produces a multiple of 10.
Example: Assume the barcode data = 5463789
(odd positions) = 5 + 6 + 7 + 9 = 27
27 * 3 = 81
(even positions) = 4 + 3 + 8 = 15
81 + 15 = 96
96 + 4 = 100 (nearest equal or higher multiple of 10)
therefore X = 4 (checksum)
ACCEPTABLE NON ACCEPTABLE
Always Ensure that coloured barcodes and backgrounds
meet requirement for scanning acceptability.
Benefits of Barcoding
• Represent unique identity of a product.
• Accuracy of data input. (Error free)
• Aid effective management of resources
• Saves labour By avoiding manual inputting system.
• Real time data collection.
• More accurate despatch.
Applications of Barcode
• HOSPITALS: Barcodes can allow for the organization of large amounts
of data. They are widely used in the healthcare and hospital settings,
ranging from patient identification (to access patient data, including
medical history, drug allergies, etc.) to medication management.
• RETAIL: Speeding up checkouts and ordering.
• OFFICE: Recording transactions.
• HEALTH: Ensuring correct dosage and treatment.
• TRAVEL: Making ticketing more efficient, ensuring safety and speedier
• LIBRARIES: Logging borrowers and books
Thank you for viewing this presentation and please feel
free to call us if you need any further advice or information
AC Labels Ltd
Unit 14 Parker Center,
Tel: +44 (0) 1332 890602