发信人: james54321 (judo), 信区: PennySaver
标 题: Manufacture Coupon UPC 秘密 ZZ精简版 1
发信站: BBS 未名空间站 (Mon May 14 17:44:09 2007)

1： UPC
"UPC" stands for Universal Product Code. UPC bar codes were originally
created to help grocery stores speed up the checkout process and keep better
track of inventory, but the system quickly spread to all other retail
products because it was so successful.
You can see the manufacturer identification number in any standard 12-digit
UPC code
You can see that the UPC symbol printed on a package has two parts:

* The machine-readable bar code
* The human-readable 12-digit UPC number
for example, picture 1:

BYG Publishing's manufacturer identification number is the first six digits
of the UPC number -- 639382. The next five digits -- 00039 -- are the item
number. A person employed by the manufacturer, called the UPC coordinator,
is responsible for assigning item numbers to products, making sure the same
code is not used on more than one product, retiring codes as products are
removed from the product line, etc. In general, every item the manufacturer
sells, as well as every size package and every repackaging of the item,
needs a different item code. So a 12-ounce can of Coke needs a different
item number than a 16-ounce bottle of Coke, as does a 6-pack of 12-ounce
cans, a 12-pack, a 24-can case, and so on. It is the job of the UPC
coordinator to keep all of these numbers straight!

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 Teenager's Guide to the Real World" example shown
above:

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.

Each time the scanner scans an item, it performs this calculation. If the
check digit it calculates is different from the check digit it reads, the
scanner knows that something went wrong and the item needs to be rescanned.


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