Barcode frequent ask question

How does a barcode work?
Most people today have seen barcodes. They are printed on nearly every item in a grocery store. These are either UPC or EAN linear barcodes. However, there are over 300 other different types of barcodes (see the Specifications Page for more information) The next most popular linear barcode is Code 39 (also called Code 3 of 9). Also, there are 2D Barcodes (see the 2D Page for more information) that can store a large amount of information in a smaller space than linear barcodes.

Most linear barcodes are nothing more than "license plates" that identifies an item. The numbers and/or letters stored in the barcode are unique identifiers that, when read, can be used by a computer to look up additional information about the item. The price and description of the item is generally not stored in the barcode. The data is read from the barcode, sent to a computer, and the computer looks up the price and description of the item from the computer's database.

Barcodes are read by either scanning a point of light across the symbol or capturing a video image of the symbol and measuring the lengths white spaces and (black bars. The lengths and positions of the spaces and bars are analyzed by a computer program and the data is extracted. The relative widths of both the bars and spaces code the data stored in the barcode. The barcode reader detects these relative widths and decodes the data from the barcode. The difference between Optical Character Recognition or OCR and barcode is OCR reads text not designed to be read by a computer while barcode reads symbols designed to be read by a computer. That makes the software less complex for decoding barcode. Also, most barcode symbologies have built-in error detection to make the decoding almost 100% accurate. For more information about how barcodes are read, see the Barcode Readers Page.

Barcodes can be printed using most computer printers. The simpliest way to print a barcode with your computer printer is to use a barcode font. You install the font on your computer just like any other font, and you can switch to the barcode font the same way you switch to any standard font. Visit the Bar Code Fonts Page for a list of free and shareware barcode fonts. If you want to print a large quantity of barcodes with data from a database, you can use a barcode font and mail merge software to do it. However, a more industrial approach is to use barcode label printing software. Visit the Bar Code Label Printing Software Page for a list of these products.

A company can also order labels preprinted with barcode from vendors that specilize in printing barcodes. The advantage over printing labels yourself is the vendor has the responsibility to print a readable barcode rather than you. Pre-printed barcode labels have the disadvantage that a inventory of labels must be maintained. To find out more information about this option, visit our Pre-Printed Bar Code Label Page.

Finally, if the barcode is a UPC or EAN barcode, it is usually printed during the printing of the product's packaging. Generally, you will have to obtain a barcode film master from a vendor that specializes in this. However, some printing companies can also do the barcode film master.

How do I get a bar code number for my product?
When someone asks this question, they are talking about the UPC or EAN symbol found on most retail products around the world. Specifically, they are asking how to obtain a UPC or EAN company identification number which they can encode into a UPC-A or EAN-12 bar code symbol on their products. In the United States of America a company can obtain a unique six digit company identification number by becoming a member of GS1-US (formerly the Uniform Code Council (UCC)). In the rest of the world, contact GS1 (formerly EAN International (EAN)). GS1 maintains an excellent FAQ, standards information and a list of member organizations around the world, many of which have web sites. The GS1 site is a must visit if you need to put a bar code on your product.

You must apply for membership and you will be assigned a unique company identification number for use on all your products. Also, take a look at our UPC/EAN page which explains how to apply for a UPC/EAN number and gives technical formation about UPC/EAN. The fee for membership is not cheap and you will have to pay every year.

What you get for your money is a unique company identification number which is a 6 or 7-digit number. This is the first part of the product UPC/EAN code. The remaining 6 digits are assigned by you (not GS1) for a specific product. Each number must be unique for a particular product and product size. If you have an 8 oz. size and a 12 oz. size, for example, you need to assign two unique numbers.

If you want to bar code a book, you use the International Standard Book Number (ISBN). If you are bar coding a monthly publication, you use the the International Standard Serial Number (ISSN). See the Bookland EAN Page or the ISSN Page.

When Do I Need To Put A Bar Code On My Products?
When your distributor or store that will sell your product requires it. There is no law that says you must bar code a product. However, many national retail chains and most grocery stores require all products they sell to have a bar code that is unique for the specific product. The stores require this "source marking" because it is easier for the company that makes the product to mark it rather than the store. If you don't have a bar code on the product, these stores will not sell the product.

What is GS1, GS1-US, etc.?
GS1 is the new name for EAN International. Also, GS1-US is the new name for the UCC or Uniform Code Council.

Do I have to join and pay GS1-US (in the USA) even if I just have one product to sell?
The answer is yes and no. First the yes answer. You will have to join GS1-US and pay a yearly membership fee to use the company prefix they assign to you. However, if you became a member before August 28, 2002, you do not have to pay the annual fee. You should read the class action settlement.

Now the No answer. According to George Laurer, the inventor of UPC, if a company joined the Uniform Code Council (now GS1-US) prior to August 28, 2002, the Uniform Code Council's membership and licence agreement did not contain any prohibition against subdividing the numbers. There are four companies in the United States that are issuing single UPC numbers are Simply Barcodes (,, and This appears to have been a side consequence of the class action settlement reached December 15, 2003 in the Superior Court in and for the state of Washington, county of Spokane. See some information here.

In addition, GS1-US has a program where companies can buy a few numbers, but it is not a good deal. You can read George Laurer's commentary about "Variable Length Prefix" (smaller subsets of UPC for small companies) here.

If you still don't want to pay the fee to either the GS1-US or the three private companies, talk to your distributor or the store chains you will be selling your product to. See if they will accept your product without barcode. Most large chains will not, but it is worth a try.

Do I have to join and pay GS1 for internal uses like inventory or other non-retail uses?
No you do not have to join the GS1 or GS1-US or pay anyone to use barcodes for internal use. In fact, you should consider some other type of barcode like Code 39 or Code 128 rather than use UPC or EAN. The reason to choose a different barcode symbology is UPC and EAN are fixed length codes. The data must be exactly 13-digits long and contain only numbers. If you have an existing inventory system with part numbers, for example, they are probably longer than 13 characters and they probably include letters. Code 39 and Code 128 both handle both letters and numbers. They also can be as long or as short as you want. Finally, both are easier to print. You can get a TrueType Code 39 font, for example, and print barcodes using Word or Excel.

If you must use UPC or EAN for the internal application, then you need to use one of the prefixes that the GS1 has set aside for internal use. See the table, and look for the prefixes that say "Restricted distribution (MO defined)"

A company is offering to sell me a single product number. Is this legitimate?
According to George Laurer, the inventor of UPC, if a company joined the Uniform Code Council prior to August 28, 2002, the Uniform Code Council's membership and licence agreement did not contain any prohibition against subdividing the numbers. There are four companies in the United States that are covered under the pre-August 28, 2002 UCC agreement and are subdividing their numbers. These companies are Simply Barcodes (,, and This appears to have been a side consequence of the class action settlement reached December 15, 2003 in the Superior Court in and for the state of Washington, county of Spokane. See some information here.

In addition, the UCC has a program where companies can buy a few numbers, but it is not a good deal. You can read George Laurer's commentary about "Variable Length Prefix" (smaller subsets of UPC for small companies) here.

If I Change The Size Or Formula Of My Product, Do I Need To Change The Barcode?
Stores use the product's barcode to determine the type and cost of a product being sold. Some use the barcode to maintain inventory and to reorder. Let's say that a soft drink with a particular UPC barcode is sold in 16oz sizes. The manufacturer discontinues 16 oz sizes and change the size to 15 oz. Since stores often print a short description that includes size on the customer receipt, not changing the UPC could result in an incorrect size being printed on the receipt and an angry customer. If you can assure that the descriptive databases of all the stores that sell your product will be updated with the new description, you might get away with not changing the UPC barcode. However, this assurance is almost impossible these days with international sales. The safest is to change the barcode.

How Do I Get A List Of All The Product Codes And Their Respective Manufacturers?
If someone is opening up a hardware store, for example, it would save a lot of work to have a database of all the product numbers of the products carried by the store with their descriptions. The store, of course, would still have to enter the selling price for each product. The second reason for wanting a list of product codes is to identify the company that made the product.

There is now a complete, free on-line database that allows anyone to type in a UPC or EAN number and get the company name and address for the product. It is a project developed by GS1 and is called GEPIR. The number contained in the UPC or EAN barcode is now called the Global Trade Item Number or GTIN. You can go directly to the UPC and EAN search page by clicking here. Please note that sometimes GEPIR is down. If you get a "page not available", try later. Currently, the database contains some product descriptions. Searchin "trade item ownership" will returns the company name and address. Some records may contain the telephone number of the company. The web service is based on XML, so it is possible to integrate an application program with this database. That means that it will be possible for a small store to scan the barcode on a product, access GEPIR over the internet, and download product and manufacturer information over the internet to build a local database of products in the store for free. GEPIR is under continuous development and will soon also provide product images, dimensions, carton sizes, tracking and tracing data. This database is open to consumers as well as companies (unlike UCCNet, a project of the GS1-US).

There are other sources available too. There is a new resource for searching EAN barcode numbers at You can search for EAN codes or browse through the database of over 500.000 EANs. There is a site which provides product descriptions. It's called the Universal Product Code Database, an on-line database for Universal Product Codes (UPC). You now can purchase a UPC database from Gregg London. The UPC Database Project is another public UPC database from Glenn J. Schworak. The site also has links to other UPC databases. Swiss companies and EAN/UPC codes can be looked up at EAN Switzerland.

If you are opening a store, you should ask your suppliers if they have their UPC product codes in a database you can download. If you have to build your database by hand, the best structure is to have a database entry system that allows you to scan the UPC on a product and then key in the description. That way you make use of the UPC bar code for at least some of the data entry.

1SYNC (former UCCNet) is a project of GS1-US to synchronize data between trading partners. Unfortunately, there is no "public access" to the data being stored. If you are Wal-Mart or Home Depot, you can synchronize data from suppliers. If you are a small one or two lane Grocery store, you will NOT be able to obtain the databases from Pepsi - as an example.

Does the barcode number indicate the country of origin of a product?
No it doesn't. The 3-digit prefix code indicates which GS1 numbering organization has allocated the block of numbers to the company. Once the company has been assigned the block of numbers, they self assign each individual number in the block to a given product. For example, a company may have it's headquarters in South Africa. The GS1 organization in South Africa has the code "600", but all the products of the company may be manufactured in England. The English-made products would still have the "600" prefix code. The prefix code is a way to have 70-plus GS1 member organizations issuing numbers without having to worry about duplicate numbers. The 3-digit prefix indicates the country of the GS1 organization that issued the block of numbers, not the country of origin of the product. GS1 (the international organization that administers UPC and EAN) has a clear statement that the prefix DOES NOT indicate the country of origin of the product. A list of country codes can be found on the UPC & EAN Page.

My product has an EAN barcode. Do I need a UPC barcode to sell in the USA?
As of January 1, 2005, all retail barcode systems are required to read both EAN and UPC. You no longer have to use UPC in the USA. Please see the white paper that explains this change. You do not have to use UPC.

My product has a UPC barcode. Do I need an EAN barcode to sell outside the USA?

UPC barcodes were always readable by EAN scanners outside the USA. As of January 1, 2005, all retail barcode systems worldwide are required to read both EAN and UPC. Please see the white paper that explains this. You do not have to use EAN

Does the barcode number contain the product price, age, or store it was purchased from?
Most barcodes found on products are UPC or EAN barcode. These barcodes only can store numbers and the data is always 13-digits long. The product barcode is nothing more than a unique number that identified the type of product For example, all 12oz boxes of corn flakes from the same manufacturer will have the same bar coded number. In general, the product barcode does not contain product price, age or store it was purchased from. When the barcode is scanned, the number is looked up in a database which contains a description and price for the product.

How do I bar code books, magazines, CDs, and DVDs?
If you have a ISBN number for your book, you don't have to get a separate number from the UCC or EAN. You use the ISBN (International Standard Book Number). You can also read the barcode on the book and extract the ISBN from the barcode. Find out more by visiting BarCode 1's Bookland EAN page.

If you have a ISSN number for your magazine, you don't have to get a separate number from the UCC or EAN. You use the ISSN (International Standard Serial Number). You can also read the barcode on the magazine and extract the ISSN from the barcode. Find out more by visiting BarCode 1's ISSN page.

If the stores you plan to sell your CD through do not require a barcode, don't worry about putting a barcode on your CD. The store will put a barcode label with an internal number on the CD. However, many store chains do require a UPC-A or EAN-13 barcode before they will accept the product for sale. If you are self-publishing a single CD, you can purchase a single product number from Simply Barcodes (,, and

If your CD is a talking book, it is within the scope of ISBN, according to the latest Users Manual at ISBN International. An ISBN is less expensive than joining the UCC and you don't have to continue to pay an annual fee, like you do now with UCC membership. Once you get your ISBN, you follow the process outlined at the Book Industry Study Group web site.

Can barcodes be read upside down?
Yes. Each barcode (whether it is UPC, EAN, Code 39, etc.) includes a start and stop character. Depending which is encountered first will tell the scanner what direction it is reading the barcode. With that information, the decoder can properly read the symbol.

Can I Print The UPC Bar Code In A Color Ink or On Colored Paper?
It is risky. Color ink and/or colored paper will reduce the contrast between the bars and spaces. Also remember that many scanners use red light. If you print the bars using any shade of red, the same amount of light will reflect off the red bars as the white spaces. Also, printing black bars on a colored paper will also reduce the light reflecting off the spaces and reduce the contrast. Other colored inks will also reduce the contrast ratio between the bars and spaces and greatly increase the probability of an unreadable barcode. If the black bars and white spaces are too glossy, the symbol also may not read. A real no-no is printing black bars on a silver can.

Many large chains now fine or disqualify vendors who supply products with bar codes that do not scan. If you print the UPC symbol with color ink, you run the risk that the symbol will not scan. That could result in you losing a big customer.

Can I reduce the size of a UPC/EAN barcode to fit a smaller space?
It is very risky to reduce the size of a UPC symbol. The nominal size of a UPC symbol is 1.469" wide x 1.02" high. The minimum recommended size is 80% of the nominal size or 1.175" wide x .816" high. The maximum recommended size is 200% of the nominal size or 2.938" wide x 2.04" high. Larger UPC's scan better. Smaller UPC's do not scan as well or not at all.

Ink spread can also decrease the flexibility of size reduction of a bar code. If a bar code is reduced too much, an attempt to silk screen print it will blur the bars together. This is one of the reasons why it is recommended to keep the bar code within the minimum of 80% of the nominal size.

If you must reduce the size of a UPC symbol, consider using GS1 Databar.

Many large chains now fine or disqualify vendors who supply products with bar codes that do not scan. If you reduce the UPC symbol below the maximum recommended, you run the risk that the symbol will not scan. That could result in you losing a big customer.

How can I identify what type of barcode is being used? Can you identify a barcode for me?
First, don't send me a picture of it! Most pictures I receive simply are not good enough to do any identification. I will not identify any barcodes sent to me. You generally cannot identify the type of barcode by looking at it.

It really is not important any more to know the type of barcode in order to read the barcode. Most modern scanners will automatically detect the type of barcode and read it correctly. This is called auto-discrimination. If you really want to know the symbology used, you will need to buy a barcode verifier (between $800-$1500). You might also contact the source of the barcode and ask.

What are the advantages and disadvantages of barcode?
There are two basic advantages to barcode over manual data entry: Speed, and Accuracy. For 12 characters of data, keyboard entry takes 6 seconds. Scanning a 12 character barcode takes .3 seconds. The error rate for typing is one substitution error in every 300 characters types. Error rated for barcode range from 1 substitution error in every 15,000 to 36 trillion characters scanned (depending on the type of barcode). A data entry error will translate into additional costs for a business which ranges from the cost of rekeying the data to shipping the wrong product to the wrong customer. Saving from these two advantages will usually pay for the cost of a barcode system in under two years.

The only disadvantage is that data must be coded in the barcode. This can be an additional cost, however the key to an effective barcode system is to generate the barcode as close to the source of the data as possible. That means that the source of a product should be bar coding data that others in the supply chain will use.

Where Can I Find Market Research & Statistics On Cost Savings, Labor Saving, Accuracy, Etc. For Barcode Systems?
The best source of current statistical information about barcode and other Auto ID systems is Venture Development Corporation. There are white papers and press releases at their site that can be downloaded for free. Other studies you will need to pay for.

The BarCode-1 Market Research Page includes information gathered from visitors who answered are questionnaire.

Based on 1283 respondent end users, about 80% of users found that barcode equipment ROI was less than two years (45% found that ROI was less than 1 year). Quickest payback occurred for companies with between 500 and 999 employees. The study also found that 50% found direct dollar savings to be more than $25,000 (1986 dollars) a year and nearly 25% found direct dollar savings to be $100,000 (1986 dollars) per year. Indirect savings was found to be about the same as direct savings.

The simple fact is that barcode data entry if far faster and more accurate than key entry. For 12 characters, key entry takes 6 seconds, while barcode takes less than .5 seconds. Error rate for key entry is typically 1 substitution error for every 300 characters. Barcode error rate depends on the type of barcode and varies between 1 substitution error in 15,000 to 36 trillion characters entered. For UPC (11-character symbol) one analysis by David Savir suggests 1 substitution error in 15,000 UPC barcodes scanned. The chances that the misread product number would match a number (for the wrong item) comes out to 1 chance in 100 million UPC symbols scanned. Interleaved 2 of 5 has the worst error rate. For an I2 of 5 symbol of at least 10 or more characters has an almost 100% chance of being read in error. Code 39 has a substitution error rate of 1 character in 3 million characters.

Won't RFID tags make barcodes obsolete?
RFID (Radio Frequency Identification) tags will never take the place of barcodes. All RFID tags contain a radio transmitter, receiver and a microcomputer. Barcodes are made up of ink. The relative cost of RFID tags compared to barcode is the primary reason why they will never replace barcode.

To make RFID tags worth the additional cost, they must be used more than just at the check-out register. That means embedding the tag in the merchandise rather than just in the packaging (because the packaging gets thrown away by the customer). Since the item will always contain a working RFID tag, it could be read for a variety of purposes. For example, an RFID tag in a pair of shoes could be used to track an individual as they shop at a shopping mall. If one paid for the shoes with a credit card, the unique ID of the shoes could be matched to an identity. The potential for the loss of privacy is the second reason why RFID tags will not replace barcode.

What barcode will let me store the most information in the smallest space?

The popular linear or 1D barcode that that will store the most numbers and letters in the smallest space is Code 128. However, any 2-D barcode will store far more information per square inch than any linear barcode

How small can I make a Code 39 or Code 128 barcode?
The smallest x-dimension possible with current printing and reading technology is 5 mil. The safe limit is 7.5 mil. There are Javascript programs for calculation the length of both a Code 39 and Code 128 symbol here at BarCode-1.

Code 93 is not as widely used but would provide an even higher density than either Code 39 or Code 128.

There are other code formats that can store even more info in a small space. 2-dimensional symbologies can store a great amount of alphanumeric info in a very small space. The tradeoff is that these 2-D symbologies require more expensive scanners.

It is possible to print such a barcode using a laser or inkjet printer. Best bet would be to use a 600 dpi model. A 300 dpi model will be right on the edge for a 7.5 mil barcode (only about 2 dots across).

What are the codes that look like a grid of hexagons or squares? What are 2-D barcodes?
These codes are called 2-dimensional barcodes, matrix codes, or stacked codes. There are a number of these codes that are gaining in popularity. They are Code 49, 16K, Code One, PDF417, Maxicode, Vericode, and Datacode. The best bet for widespread adoption is PDF417 for "paper databases", Maxicode for shipping information, and Datacode for micromarking applications like integrated circuits. Take a look at the BarCode-1 2-D Page.

Where can I get the specification for a particular barcode?
There are many different barcodes. UPC is one, Code 39 is another, and 2 of 5 is a third. Each are entirely different codes. There are more than 300 different types of barcodes. There is a list of specification sources for the more popular ones on Barcode-1.

How do I print a space, carriage return, tab or function key using barcode?
For Code 128, look at the Code 128 table The value under Code A that says "SP" is a space. The ASCII value is 32

For Code 39, try using the tilde ("~") instead of a normal space. Some fonts also define a space character with an underscore ("_"). You can also try setting the true type fonts as graphics in the printer driver settings. This will will print a space as a barcode space, and not as white space. Remember, if you are using a code 39 type font, you'll need to put an "*" at the beginning and end of the data. That's because the "*" is the start and stop character for code 39.

Carriage return and Tab
For Code 128, look at the Code 128 table The value under Code A that says "CR" is a carriage return. The ASCII value is 109. The value under Code A that says "HT" is a horizontal tab. The ASCII value is 105

Code 39 has no carriage return or tab. If your barcode scanner is a programmable keyboard wedge, you can usually program the wedge to add a carriage return or tab to the scanned data. You can also modify your application program. For example, if you are reading in a 6-digit number, you can program a Visual Basic routine to skip to the next field when 6 digits are inputted. Finally, you can use the "+" sign in Code 39 as a carriage return or tab and add it to the data you are encoding. Then the wedge or software can translate the "+" into a CR of HT when read.

Function Keys
Barcodes cannot encode keyboard function keys. The reason is that function keys (F1, F5, etc.) are unique to the hardware and are not an ASCII code. For a PC keyboard, function keys transmitted as keyboard scan codes and have no equivalent ASCII control codes that can be coded as a barcode. However, there is a work around. Many keyboard wedge scanners can be programmed to substitute a function key each time they scan a specified character. Since a keyboard wedge reader use the same data transmission standards as a keyboard, they can send a scan code representing a function key. For example, if the application will never need a plus sign (+) in the barcode, the keyboard wedge replace plus signs with F5 keys. If "12345+" was scanned, it would produce the data stream "12345" followed by the F5 key. This same approach may be used even with bar code readers attached to a serial port if a "soft wedge" is used. This "soft wedge" is a program that takes data from a serial port and treats it as if it had come in through the keyboard. Some of these programs also allow character substitution.

How Can I Keep A Barcode From Being Copied?
A readable copy of a barcode can be made using modern copy machines. However, one can prevent the barcode from being copied by using a special over laminate that only allows infra red light to pass through. The barcode in printed, for example, on a security badge and the infra-red transparent laminate is placed over the barcode. If someone attempts to remove the laminate, it destroys the barcode. The barcode must be read using an infra-red scanner.

Using Barcodes With Other Programs And On The Internet

Can barcodes be used with Word, Access, Excel, or Clipper for scanning and printing?
Yes. It's pretty easy. You need to get a scanner that has a "keyboard wedge interface" and a built-in decoder or a "software wedge" and a scanner with serial output. A wedge interface works like a really fast typist on a keyboard so it's easy to connect and use. Some wedge readers are programmable, so that after the scan, a "return" or tab will be produced to move the cursor to the next field

To print barcodes you can use just a TT font. There is some problems with TTF barcode printing. The fonts may not print properly for very small or very large point sizes. If you want to print a barcode in a report or document (from Word or Access for example), the easiest True Type barcode font to use is Code 39. You have to pre-pend and post-pend the "*" to the data you want to print as barcode and then just change the font to Code 39. You can also do this for printing labels from Word. You can find free and shareware barcode TT fonts here.

If you need to print using Access 2000, try "*" & [FieldNameWithValue] & "*". If you need to print using Clarion, the format is loc:barcode='*'&left(clip(KAT:ID_NUMBER))&'*'.

A better solution for print labels, is a stand alone program to print the labels. Many of these programs can connect to Access via ODBC and will let you print labels from a database. For example you can list all the parts that you have in a database and have the label program pull the part numbers from Access and print them on a label printer rather than typing them by hand each time you want to print. You can find free and shareware stand alone programs here.

Some people have had problems moving an ActiveX barcode control into a table in Word. The control appears outside the table. The solution is as follows. Right-click on the control, choose Format...object. On the Position tab, uncheck the "Float over text" check box. You should be able to move the control in to a table cell. You can find ActiveX controls on our Plug-ins page.

Finally, if you are developing your own Access-based program, there are OCX and dll tools that allow you to add barcode printing to your program.

How do I calculate the Mod 10 check digit or the necessary Check Digit for a given code?
More information about calculating a Mod 10 check digit can be found at the bottom of the Interleaved 2 of 5 Page. Please note that each barcode symbology that uses a modulo check digit has a method defined by its specification. Code 39 does not normally need a check digit, but there is a check digit system defined in the specification. See the Code 39 specification page. Code 128 uses Mod 103.

Can barcodes be used in a web environment?
Yes they can...both for printing barcodes and reading barcodes. For printing barcodes through a web page, see the BarCode-1 Web Apps page. If you have control of all the computers that will be printing the barcode, you can use a ttf barcode font to print the barcode too. Just download the ttf barcode font to each computer and then use the HTML code to sent the font. The sample html code looks like this : <FONT FACE="3 of 9 code" SIZE=5>*12345*</FONT>

To read a barcode into a web form, just use a wedge barcode reader. This type of reader (most barcode readers these days are wedge readers) plugs in between the keyboard and computer. When you scan the barcode, it is as if you typed the data. You can use some Javascript to set the focus to the input box too. The code looks like this:

For the page body tag use something like: <BODY onLoad = "document.forms.ShipForm.IDNUM.focus()">

Then name the FORM tag like: <FORM ACTION="http://yourdomain.cgi" METHOD="POST" NAME="ShipForm">

And finally name the input box tag like: <INPUT TYPE="text" NAME="IDNUM" SIZE="14" MAXLENGTH="14" VALUE="">

This JavaScript will work for IE4+. It has not been tested with Netscape or other browsers.

Can I use a Palm Pilot, iPAQ or other PDA to scan bar codes?
Yes. If you already have a Palm Pilot, look at the Portable Technologies site. The company makes a barcode reader interface for the Palm.

Also, Grabba International Pty Ltd makes scanners that connect Palm, iPAQ and other PDAs. They also offer RFID, mag stripe and other auto ID devices for PDAs.

Another alternative is to buy a PPT8000 Palm Computer. These versions, made/modified by Symbol Technologies, come with a built-in laser bar code scanner. Also, a nice retail application and inventory application is available from Stevens Creek Software. Peninsula also sells the SPT1500 and SPT 1700.

Where can I find parts to build a barcode scanner?
I only know of a few companies that provide components for bar code scanners. Agilent is one. They have everything from opto-electric sub assemblies to ICs for decoding the barcodes. Opticon also have similar sub assemblies. Finally Symbol Technologies sells scan engines for laser scanners.

There also is also software available (code 39 and Interleaved 2 of 5 for free) that allows a "dumb wand" (just a light source and photodetector) to be plugged into a serial port. The decoding occurs within the computer.

What is the least expensive barcode scanner and where can I find it?
The least expensive barcode scanner is CCD scanner (about RM 180). The most expensive (but most versatile) is the laser scanner (RM 450 up). These scanners come with a PS/2 keyboard wedge. If you want to connect the scanners to USB (for example a laptop), you will need to purchase a PS/2 to USB adapter.

Can I Read A Barcode Image Off An LCD Or CRT Screen?
Believe it or not, yes! I did not believe it until I tried it. You need to use a CCD barcode scanner, not a laser scanner. You also have to play with the font size and get a size that is big enough.

The reason a CCD scanner will work and a laser scanner will not is as follows. A CCD scanner has a video camera that takes a picture of the entire barcode. A laser scanner scans a beam of laser light across the barcode and picks up light reflected by the white areas of the barcode. The “white” areas of a barcode on a computer display are not reflecting light but rather are emitting light. Therefore, a laser beam cannot be scanned across the barcode and the laser scanner cannot pick up reflected light from the “white” areas. In fact, the laser light will be equally reflected by the surface of the computer screen and the laser scanner will not detect any barcode on the screen.

If the scanner charges me the wrong price, doesn't the law say I get the item free?
There is no state or Federal law in the United States that requires this. Stores normally will give the customer the lower price, but there is no law that forces them.

Improper pricing is not the result of barcode scanner errors. It is a result of improper or out-of-date shelf prices or signs. Barcodes do not contain the price of an item. The barcode contains a unique number that indicated to the store's computer what the item is. The computer contains a database that matches this item number to the price for the item. This price is sent back to the point-of-sale terminal. If a sale ends, there sometimes is a delay between when the sale sign is taken down and the database is updated. When these mistakes occur, usually the database is correctly updated, but the store forgets to take down the sale sign. This results in the customer being charged more for the item than they expected.

Laws dealing with this situation usually fall within the state's department of weights and measures and usually only require a store to have policies of what they will do in such situations. For example, see Arizona's law section 41-2081(M)(2). Often, a state's department of weights and measures will do a test at a store. If the errors exceed a certain percentage, the store may be find.

Is there a hidden 666 in bar code?
NO! What people really mean is "does UPC found on grocery products have a hidden 666 (mentioned in Revelation 13:16 in the New Testament)?" People have thought that the three guard bars used to specify the start, middle and end of a UPC bar code looked like the bar code sequence for a "6" found in the UPC symbol table. You can find a copy of the symbol table on the UPC/EAN page. These guard bars are not "6" and carry no information. Even if you don't believe that guard bars carry no information and insist on applying the code table, you have to determine whether the digit is on the left side or the right side of the symbol. That's because the sequence of bars and spaces are different depending on whether the digit is on the left of the symbol or the right of the symbol. The LEFT guard bar would have to be smallest space, smallest bar, smallest space, WIDEST BAR in order to be a "6". The guard bar on the left is actually space of undetermined wide (left side digit must always start with a space element), smallest bar, smallest space, smallest bar. That sequence of bars and spaces is undefined and is not a "6" even using the table. The middle guard bar is not on the left or the right ('cause it is used to divide the symbol), so it is undefined by the table.

UPC is just one bar code symbology out of over 300 others. The bar code on the backs of some driver licenses, for example, is not UPC and has no guard bars at all. A much better "marks of the beast" than barcode would be finger prints, DNA typing, or plain automatic face recognition. These are all "source marking" (marks put on during manufacturing) and are far more cost-effective. "No Hidden Sixes in the UPC Barcode" by Robert Harris of Southern California College / Vanguard University is another good explanation.