check digit
Digit Check
Code 39 is the simplest of alpha-numeric barcodes to use that does not require a check digit to be calculated. Although there is a Mod43 Check digit that is required by standard for LOGMARS and HBIC barcodes. The Code 39 barcode is also known as 3 of 9 Barcode, Code 3 of 9 and Bar Code 39.
Disregard the first and last bar, they mark the beginning and end of the bar code. Each digit in a bar code is made up of 2 tall and 3 short bars, starting with the second bar read 5 bars as 7,4,2,1,0. which ever numbers has the tall bars add them to get the first digit of the bar code. 7 and 4 is 0.
The first 2D Bar codes where used on Railroad Cars. Check the related link
check digit
Digit Check
The last digit of the postal barcode is a check digit, calculated based on all the other digits to facilitate validation of the scanned code and thus prevent misreads.
Code 39 is the simplest of alpha-numeric barcodes to use that does not require a check digit to be calculated. Although there is a Mod43 Check digit that is required by standard for LOGMARS and HBIC barcodes. The Code 39 barcode is also known as 3 of 9 Barcode, Code 3 of 9 and Bar Code 39.
Disregard the first and last bar, they mark the beginning and end of the bar code. Each digit in a bar code is made up of 2 tall and 3 short bars, starting with the second bar read 5 bars as 7,4,2,1,0. which ever numbers has the tall bars add them to get the first digit of the bar code. 7 and 4 is 0.
it calculates the checkdigit based on the number read. if the check digit calculated matches with the one read then barcodes has been read correctly.
vin number or vehicle number
Assuming you mean the 13 digit bar code and by "combinations" the mathematical permutations, then there are 1012 different bar codes - the 13th digit is a check digit based on the other 12. On the 8 digit bar code there are 107 different bar codes - the 8th digit is a check digit based on the other 7. "Combination" has a specific meaning in maths: Permutations are sets arranged in order whereas Combinations are sets where order does not matter. So for the six sets: {1, 2, 3}, {2, 3, 1}, {3, 1, 2}, {1, 3, 2}, {2, 1, 3}, {3, 2 1} they are different permutations of the digits 1, 2 & 3 (as the order changes each time) but the same combination (as each set contains one 1, one 2 and one 3 in some order). The same is true of the six numbers: 123, 231, 312, 132, 213, 321 They are different permutations of the three digits 1, 2 & 3 but the same combination of them - each number contains one 1, one 2 and one 3.
The first 2D Bar codes where used on Railroad Cars. Check the related link
bar codes work by when the scanner scans the bar code, its looks through the numbers and recognises the item and the price. this is because when the product is made its bar code is made to recognise the item and it is put a price on. they use computer technology to do all of this.----Basically its till scanners or laser readers consist of a light source and a photo diode that are placed next to each other in the scanner housing (or hand held scanner). To read a bar code, you pass the item across the scanner in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source (the bar-code white and black lines) and generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is an exact duplicate of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse Code dots and dashes are decoded. It then interprets the wave form in to a numeric code.i.e.The last digit of the UPC code is called a check digit. This digit lets the scanner determine if it scanned the number correctly or not. Here is how the check digit is calculated for the other 11 digits, using the code 63938200039 from "The Answers.com world of wonder " (made up name )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 = 32Multiply that number by 3.32 * 3 = 96Add together the value of all of the digits in even positions (digits 2, 4, 6, 8 and 10).3 + 3 + 2 + 0 + 3 = 11Add this sum to the value in step 2.96 + 11 = 107Take 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 = 110The check digit is therefore 3.Once the computer (the till or the computer the scanner is attached to) is satisfied that the check digit is right it searches for the code, 63938200039 in its database and when found returns the price, description etc . The same system is used for most products that carry a bar-code from retailers to warehousing to manufacturing to UPS sending parcels world wide.In the case of a retailer the code, in this case 63938200039 starts life being punched in to the computer which drives the tills. The code is added and a description, price etc is attached to that number. In a retail outlet the company use their own internal code to start the process i.e. 1234 = 750ml bottle of pepsi (or any-other drink) attached to that internal code is the bar-code given to the retailer by the supplier. This is because a product carrying a bar-code can have different information attached by the manufacturer. as an example pepsi in our case on the shelf as a special offer attached to the label. The customer saves 5 labels and sends to the company and gets a free pepsi glass the bar code of a normal (no offer bottle ) may have 63938200039 as its code. The offer bottle will have to have a different bar code because technically there has been a change in some way to the "normal" product so the new code could be 63938200044. The manufacturer tells the retailer of the new code and in the till system now has item;1234 - Pepsi 750ml bottle - 639382000391234 - Pepsi 750ml bottle - 63938200044The database will now recognise either bar-code as Pepsi 750ml Bottle. This is why on occasion when you arrive at a till in a store they scan the barcode and the till cannot recognise it. The till operator calls for someone to check this - Then it is frequently found that a batch of products has not had its barcode number ntered to teh system.
Download an app for your smartphone that has a bar code scanner. It will help you check prices when you're at the store and see if you've overpaying. Some bar codes even have extra information and coupon deals written into them when you scan them.
bar codes work by when the scanner scans the bar code, its looks through the numbers and recognises the item and the price. this is because when the product is made its bar code is made to recognise the item and it is put a price on. they use computer technology to do all of this.----Basically its till scanners or laser readers consist of a light source and a photo diode that are placed next to each other in the scanner housing (or hand held scanner). To read a bar code, you pass the item across the scanner in a steady even motion. The photo diode measures the intensity of the light reflected back from the light source (the bar-code white and black lines) and generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is an exact duplicate of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse code dots and dashes are decoded. It then interprets the wave form in to a numeric code.i.e.The last digit of the UPC code is called a check digit. This digit lets the scanner determine if it scanned the number correctly or not. Here is how the check digit is calculated for the other 11 digits, using the code 63938200039 from "The Answers.com world of wonder " (made up name )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 = 32Multiply that number by 3.32 * 3 = 96Add together the value of all of the digits in even positions (digits 2, 4, 6, 8 and 10).3 + 3 + 2 + 0 + 3 = 11Add this sum to the value in step 2.96 + 11 = 107Take 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 = 110The check digit is therefore 3.Once the computer (the till or the computer the scanner is attached to) is satisfied that the check digit is right it searches for the code, 63938200039 in its database and when found returns the price, description etc . The same system is used for most products that carry a bar-code from retailers to warehousing to manufacturing to UPS sending parcels world wide.In the case of a retailer the code, in this case 63938200039 starts life being punched in to the computer which drives the tills. The code is added and a description, price etc is attached to that number. In a retail outlet the company use their own internal code to start the process i.e. 1234 = 750ml bottle of pepsi (or any-other drink) attached to that internal code is the bar-code given to the retailer by the supplier. This is because a product carrying a bar-code can have different information attached by the manufacturer. as an example pepsi in our case on the shelf as a special offer attached to the label. The customer saves 5 labels and sends to the company and gets a free pepsi glass the bar code of a normal (no offer bottle ) may have 63938200039 as its code. The offer bottle will have to have a different bar code because technically there has been a change in some way to the "normal" product so the new code could be 63938200044. The manufacturer tells the retailer of the new code and in the till system now has item;1234 - Pepsi 750ml bottle - 639382000391234 - Pepsi 750ml bottle - 63938200044The database will now recognise either bar-code as Pepsi 750ml Bottle. This is why on occasion when you arrive at a till in a store they scan the barcode and the till cannot recognise it. The till operator calls for someone to check this - Then it is frequently found that a batch of products has not had its barcode number ntered to teh system.