What Is Barcode And How It Work’s?

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Barcode are numeric codes accompanied by vertical lines that are machine-readable. They’re basically used for identification and tracking purposes. My company, J.M. Field Marketing, uses this technology to manage and keep track of client inventory.

What Is Barcode?

There are two types of barcodes – linear and 2D. The most visually recognizable, the UPC (Universal Product Code), is a linear barcode made up of two parts: the barcode and the 12-digit UPC number. The first six numbers of Barcode is the manufacturer’s identification number. The next five digits represent the item’s number. The last number is called a check digit which enables the scanner to determine if Barcode was scanned correctly or not.

UPC(Universal Product Code) Barcode was earlier invented to keep better track of inventory of grocery items. Later it got spread to other products too.
Now to get permission to use Barcode by any company, it has to apply to UCC(from where UPC originated). Then UCC gives them a 6 digit manufacturer code.

Any UPC is of 12 digit and consist of 2 parts

  1. human readable numbers
  2. machine readable barcode.

Out of these 12 digits first 6 are for determining manufacturer. Next 5 are to determine item. The last digit is check digit. The check digit works as follows:-

  1. Add together the value of all of the digits in odd positions (digits 1, 3, 5, 7, 9 and 11). 6 + 9 + 8 + 0 + 0 + 9 = 32
  2. Multiply that number by 3. 32 * 3 = 96
  3. Add together the value of all of the digits in even positions (digits 2, 4, 6, 8 and 10). 3 + 3 + 2 + 0 + 3 = 11
  4. Add this sum to the value in step 2. 96 + 11 = 107
  5. Take the number in Step 4. To create the check digit, determine the number that, when added to the number in step 4, is a multiple of 10. 107 + 3 = 110 The check digit is therefore 3.

This check digit is used by machine to check whether the item scanned is proper or not.

How Do Barcode Scanner Work’s? |Barcode Decoded

Let’s start from something which you would already be knowing. All Barcode look similar – atleast when viewed from distance. They have the same alternating black and white lines (always). Plus there is one more similarity – there are exactly 95 lines of those.

So let’s build on from here. There are 95 columns evenly spaced. Some columns appear thicker when a group of columns are of same color, both black and white. See the top of the barcode below


Next, when the laser light falls on this set of parallel lines the white lines reflect most of the light while black lines don’t. Now a computer can understand only two numbers – either 0 or 1. So it treats dark lines as 1s and white lines as os – ya it is not so intuitive, but it is so.

Time to go into more detail now.

The first line reflects none of the light (or very less light) – Hence assigned the digit 1. The next line reflects almost all light – hence assigned 0. In the same manner all columns are assigned the numbers. Total assignations  – 95. Note that these numbers are different from the one actually put below. After this, these 95 numbers are grouped in 15 different sections. 12 of these sections are used for the actual visible numbers and remaining 3 act as guards – Left Guard, Center Guard and Right Guard. You can see that in each bar code the left, the right and the center sections are similar.

The patterns for the left side code are shown below –
The pattern for the right side is similar except that it has an even number of 1s. This helps the computer to figure out which side is left/right, in case the product has been turned upside down! There is one more check for this. All the codes for the left side begin with a 0 while those for the right side begin with a 1, leaving the guards.

Each of the above 6 vacant spaces on either side represents the numbers you see on the Barcode

Okay now we have got the numbers, what do they actually mean?

1. The very first number decides the type of product – Standard, weighted items, pharmacy, coupons etc.

2. The next 5 sets of numbers tell who the manufacturer of the product is.

3. The next 5 sets of numbers tell the product code.

4. Finally the final digit is called Modulo check character. It is used for error checking. It is an important number, and its functioning is explained below.

To get the Modulo check character:

Add all the digits at odd places. There are 11 digits (leaving the Modulo number)

So for the above figure it is 

0+6+0+2+1+5 = 14 : Multiply it by 3  to get 42

Now add the even digits: 3 +0+0+9+4 = 16

Add both: 42 + 16 = 58.

Now the modulo check number is obtained by subtracting this from the next higher multiple of 10. Here 60 – 58 = 2 –> The Modulo number.

This is how the scanner verifies that the code is correct or not.

Now do Barcodes have information on price?

Yes, but not directly. After scanning the barcodes, the scanner sends
the code to a central computer and from there it fetches the price. By this the price of the product can be changed accordingly at the central Point of Sale computer.

Here Is  a video to help more in understanding:

Hope You Like Our Short Post On How Barcode Work’s and what is it Explained briefly. Do leave a comment what you want to know about next




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Comments 7

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  1. Wow that’s very interesting. I knew there was meaning to this but could never figure out all of the details. Thanks for sharing.

  2. I had read somewhere that the reason some companies prefer 2D barcodes over linear barcodes has to do with it taking up less space. I guess 2D barcodes would be more ideal for companies that use smaller packaging.

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