bar code magic

How do manufacturers use original/unique bar codes…Say I have a new widget…a combination hair curler/flashlight…what bar code design do I put on the box, so it’s unique (assuming it has to be unique)?

There are many, many bar code schemes.

Most of us are familiar with UPC, but that’s not generally used for a company’s own accounting purposes.

One of the common other bar codes is called "Code 39’ or “Code 3 of 9,” which is what my employer uses for inventory accounting. In that scheme, each digit in your widget translates to 9 bars (both light and dark), three of which are wide bars.

The postal service uses something (I think) called “Code 25” or “Code 2 of 5” for bar-coding ZIP codes. In that scheme, the bars are all the same width, but the height varies. Each digit in the 12-digit ZIP is denoted by 5 bars, 2 of which are long bars. The entire ZIP is enclosed by long bars.

That is, presumably a company has their own system of assigning part numbers that. That company-assigned part number is then translated digit-by-digit into a bar code.

A barcode is nothing more than a machine readable arrangement of bars that are an encoded number (encoded as bars, not encrypted). It’s the number the barcode represents that is unique, and probably standardized, as in a UPC.

There’s an endless variety of standardized numbering schemes: UPC, HHT, i 2 of 5, UCC128. Some are industry standardized, some are internal to a company. How you use the numbers is up to you, though because certain numbers are standard (like UPCs, i 2 of 5s, and UCC128s), they’re a required piece of product identification for most manufacturers/retailers, whose information systems are set up to track inventory by them. At the company where I work, we’re in the process of labelling all products with i 2 of 5s (case level identification) in addition to UPCs (product level identification) because about half of our customers require it.

I design packaging. Your bar code, as I am assuming you are using it here, is unique ( I have done some internal, inventory labels) To obtain a UNIVERSAL PRODUCT CODE for your Widget , apply to the UNIVERSAL CODE COUNCIL ( it aint the government GASP! GASP! gimmee a min.) It is a voluntary group you don’t HAVE to have a UPC!!! They gonna give you a number for your company , the first half of the UPC is your company, the second half you assign, BIG WIDGET is 2233, purple widget is 22331 . The retailers puter reads those numbers and tells the cash register how much to charge the customer.UPC is not a PRICE code some retailers have their own bar codes in addition that they add, depending on heir puter. Basically UPC is a code assignened by UCC that reads as ACME CO–BIG WIDGET. Most everybody in USA has agreed to go along with this no body is makin them. Oddly enough the scanners don’t read the bars, they read the spaces between wide and narrow bars. Gets kinda tricky when your talkin hundredths of an inch and the ink spreads 50/1000 of an inch, then you got sretch on a rubber plate wrapped around a cylender. And rubber shrinks Xx/1000 of an inch per inch when it cools. No prob I got charts. Here’s a place I have refered folks to, usually they come back sayin, "wELL, i Guess i just let you handle it" I THINK!! hope i got all the ww’s in there , forgot how to do a link here, been away a while.

“Pardon me while I have a strange interlude.”-Marx

Yeah you can pretty much use whatever system you want. The only real standards are the way the scanner translates the stripes into a number. What the numbers mean is up to you.

My company makes software to generate barcodes. You buy a barcode printer, set it up on your PC and you’re ready to go. You can make unique barcodes for each of your pets, relatives and potted plants.

William Poundstone gives a pretty in-depth account of how UPC bar codes work in his book Big Secrets.

There are two thin bars at the beginning, the middle, and the end that act as frames for the groups of numbers.

Following the beginning frame are two lines that indicate what department the product is rung up under. (For instance, if the lines say “3” the register rings it up under “drugs”.)

Then comes several digits indicating the manufacturer. (As mr john already described.)

After the middle frame bars come several digits indicating which of the manufacturer’s products the item is. (BTW, the bar pattern is reversed on the right hand side of the symbol. i.e. White for black, black for white)

Finally, after the item code and before the ending frame bars is a “check digit”. There is an algorithm that takes the previous numbers and comes up with a single digit. (Poundstone explains the algorithm, which is a little longer than I feel like typing in.) The purpose of the “check digit” is to see if the UPC has been tampered with. If you take a marker and change the width of one of the lines, the “check digit” will no longer be correct.

This has been brought to you by the Department of More Information than You Needed to Know. Thank you.

Wow, I get to contradict William Poundstone.

I’m not certain what he’s referring to, but the description provided by Mr. KnowItAll is slightly off. The barcode in a UPC represents a twelve digit number. As a manufacturer, my company labels all of its products with UPCs, and we determine that twelve-digit number entirely, except as I’ll describe below. There are no numbers at the beginning or end of a UPC indicating retailer specific information; all of our products are sold to the end-user according to the UPC we provide, and that UPC is a simple serial number.

The first six digits are a manufacturer identifier, and are allocated by the Uniform Code Council upon application. The next five digits are allocated by the company issuing the UPC to a particular product. The twelfth digit is a check-digit, calculated as follows:

Take the odd digits (first, third, fifth, etc.) up to the eleventh and sum them. Sum the even digits. Add those two sums, and subtract the total from next multiple of ten. The remainder is the check-digit.

In theory, my employer should issue a unique UPC to every product. In practice, many products we make carry the same UPC because of our customer’s demands. Large retailers determine what will be on the store shelves for periods of time, typically six months (at least in our category). If a product is selling poorly, a buyer will try to replace it midstream with another one, usually a variation in color. However, because the buyer is locked into a six month planogram in their system, they can’t change it on paper, so they’ll have us change the product but leave the same UPC, which is the number their system uses to track inventory and sales.

This is a major headache for us, because it means we can’t track our products by UPC, since the UPC isn’t unique for all products. We have our own identification number, but our customer orders the product via EDI by the UPC, so what a UPC refers to is dependent on the latest (usually verbal) agreement between the buyer and our salesperson. Given the choice between a headache and a sale, though…

Staples is one of the worst retailers for this practice. We’ve not only swapped colors, we’ve arranged to sell several products at the same time under the same UPC because the buyer’s planogram allows for one UPC and they want a color assortment. The buyer satisfies her planogram requirements, and we scramble to track it all.

Your explanation of check-digits does not sound quite right. if you add the two sums, isn’t this the same as adding all of the digits? I think you might mean subtract one of the sums from the other. Also check digits are used by banks for account numbers. Some check digit algorithms allow a mis-read or dropped digit to be calculated from the remaining digits.

So could you change the barcode on something in the store so it umm came out cheaper?

Look out Handy. thats why those check numbers are there, if things don’t “add up” right the computer will reject the scan.
I suspect Mr Know It All, in quoting Poundstone, might be refering to in house bar codes. One company I am familiar with that uses their own code is Payless Cashways, a lumberyard ( homecenter) There is a relativly rabid change in popularity of consumer hardware, no. of bolts in a pack etc. by using their own code they can avoid some of the hassle hansel was stateing re staples(best alliteration I could come up with on short) notice. (I gotta look that upagainhow to do that)

“Pardon me while I have a strange interlude.”-Marx

hansel, I wonder if all the products your company produce get rung up under the same department.

Just looking around the apartment here…

Pulled about a 1/2 dozen random books by different publishers. The first digit on all of them is “7”.

Grabbed some random groceries out of the cabinet. All but one started with a “4”. The one that didn’t start with a “4” had a 5 digit number under it instead of 6 digits. Looking closely at the bar code itself, the first four lines were identical to the rest. I suspect the bar code starts with a “4” as well, but was not printed numerically under the code. (BTW – Each two lines represent one digit, except for the “framing bars” described earlier.)

Curiously, a few other items I found only had one 6 digit number on them: a can of Mountain Dew, my aftershave, and my antiperspirant. I’m not sure what to make of that.

I meant to check the formula for the check digit at work today, since it’s programmed into several spreadsheets and our database, but forgot. Monday. You’re right, though: a simple sum is the same as the odd/even digit summing. Part of my job for a year was assigning UPCs, but it was a matter of assigning the next in a five digit series on a spreadsheet and seeing what the checkdigit was. I know the odd-even selection is correct, but I think there’s multiplication in there as well.

Mr. KnowItAll, no information need be encoded in the barcode itself beyond the number it represents, since that number is associated in the retailer’s system with the department, price, etc. A UPC is a simple serial number. None of our customers have ever requested specific numbers, just that certain products carry the same UPC as others from us, for the reasons I mention above. With any computerized system (and I don’t believe UPCs were in use before the systems that processed them), it’s far easier and more powerful to treat the UPC as a data key, rather than cramming important information right on the label.

OK, I see what you’re getting at, hansel. However, I don’t see how you got the idea that the retailers had a say on the UPC codes from my posts. I’ve reread them, and I don’t think I said that. If I alluded that way, I apologize. You are of course absolutely right. The manufacturer is who selects the number.

BTW, according to Poundstone, the check digit is calculated thusly:

  1. Add together the odd digits.
  2. Add together the even digits.
  3. Multiply the sum of the odd digits by 3
  4. Add this product to the sum of the even digits
  5. Subtract the result from the next higher multiple of 10

So the number 011141 26230 comes out this way:

  1. 0+1+4+2+2+0=9
  2. 1+1+1+5+3=12
  3. 9x3=27
  4. 27+12=39
  5. 40-39=1 (the check digit)

Does this jibe with your recollection, hansel?

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To be is to do. -Voltaire
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On further investigation, I checked a couple UPC (again). What I found:

  1. Can of Kroger brand ground mustard. Check digit calculation as specified above works. Also, the bar pattern matches the number pattern (i.e. identical numbers’ bars matched each other on one side of code and reversed on the other side).

  2. Copy of Big Secrets by William Poundstone and published by Quill. Bar code pattern seems to alternate between reversals, even on the same side of the code. Also, the check digit calculation doesn’t work. (Ironic, huh.)

Obviously, there is still more to this than we know thus far.

mr. john, so cut a bar code from a cheaper product & stick it over the one on the product. should work? hoping the clerk doesn’t notice :-0

The multiplication by three is the part I left out. Yes, that sounds correct.

The reason I mentioned retailers specifying details about the UPC is that, if a retailer wants a department code in the UPC, they’ll have to get the manufacturer to label the product with a barcode including that department code, and I never received any such requests when I was handing the things out.

It wouldn’t be such a big deal for a manufacturer like the one I work for to label products according to a customer’s request (we do it all the time with other labels), but for things like canned goods, labels are printed up to a year in advance (thus, the ingredients say “may contain…” because the company hasn’t committed itself to a new ingredient, or the label switch overlaps the recipe switch somehow).

Well OK, sure, but look at it this way:

Everyone uses the same product code format as determined by the Uniform Product Code Council. This is good business. If your company’s products have a UPC symbol on them, the major retailers will be more likely to carry your product. Is it that much more of a stretch to assume that your company’s 6 digit number will have a first digit that is in keeping with the uniformity of how UPCs are used?

(I should have stated this before: the department code digit is uniform for all products. All ordinary grocery items use “0”, all drugs and health items use “3”, and so on. The retailers don’t have a say in this either. They just conform to the UPCCs guidelines.)

I’d have to check whether or not the merchant number component of a UPC is allocated according to some categorization scheme (like a dewey decimal system for goods). I’ve never heard that, and it doesn’t seem to me to be advantageous in any way. UPCs are used with computerized systems, which treat the UPC as a data key: this UPC is for this product in our database, which is in this category, has this price, etc. UPCs aren’t useful unless you’re using them in conjunction with a computerized system, which isn’t going to bother with small potatoes like ‘this digit is the department code’.

My employer manufactures injection molded plastic storage goods. Our merchant number is 762016, so all our UPCs start with a “7” as well.

Here’s a link that could prove helpful for info on UPC and bar codes in general:

BTW, the UPCC has changed its name to the Uniform Code Council (or UCC).

The “check digit” is actually a “modulo check digit” on UPCs.

The department code I referred to earlier is called a “number system character”.

The “frame bars” are called “Start/Stop characters or patterns”.

The link is provided by Tharo Systems, which makes barcode equipment.