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Barcode Font - Code 39 Full ASCII Description

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How to use Full ASCII encoding with the Standard Code 39 Barcode Font

According to the military standard for standard Code 39, you can't encode small letters, symbols or control characters. The standard provides combination of precedence codes with standard characters to make the full 128 character ASCII set. Nice words, but what does it mean?

If you wanted to encode J.Francis in a barcode, there is no way for Code 39 to do it with the standard character set. You could just convert the name to all capital letters like this J.FRANCIS. You might find yourself in a situation where you don't want all caps in your database, or that you're using the barcode to trigger a search function that is case sensitive. Standard Code 39 allows lower case entry, by the combination of 2 symbols. Encoding J.Francis would look like this:

*J.F+r+a+n+c+i+s*  (this includes the stop and start asterisk)

As you might infer from the example above, lower case letters are simply the standard capital letter preceeded by a + sign. You can also encode brackets, upcaps, slashes, etc. Any key that is on your keyboard. Here's a list of all the symbols you can encode using the precedence codes:

Full Ascii Codes - Code 39 Standard
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Check your scanner

In order for your barcode scanner to interpret pairs of characters as the equivalent ASCII character in the table above, the reader must be in "Full ASCII" mode. Without this setting, the scanner will read both characters separately. To see how to program your barcode scanner, click here.

Important Usage

One of the most often questions we've handled is how to combine the barcode to fill in multiple fields on a data entry form. By using the Full Ascii character set, specifically the control codes, you can encode multiple fields of data, and enter them with one scan. Look at the following simple example:

Full Ascii Code 39 Example 1

Above is a simple data entry form for a scrap yard.  The operator would normally enter the material type in the top left field, hit the TAB key, then key in the weight of the shipment in the top right field. He then presses ENTER to record the transaction on the order ticket, and the information is transferred to the list box under the input boxes. To automate this process, he could scan the material code, then hit TAB and enter the weight. A more effecient way to perform the operation would be to make the code on the material box contain all the information for the transaction line.

Lets say that the next item in the shipment is a box of Zinc that weighs 55 pounds. The input to the computer should be "Zinc"<TAB>"55"<ENTER>. We can encode this using the Full ASCII character set of the Code 39 Standard barcode font. Using the chart above, we can see that <TAB> is represented as $I and the Enter key is a Carriage Return, represented as a $M. The string that should be encoded in the barcode is as follows:


The barcode would look like this: Example Control Codes in Code 39 Barcode

Since this looks rather strange, it probably makes sense to use the "Bold" font to eliminate the actual characters, then add the information so it makes sense to the person looking at the barcode. Something like this:

Bold Code 39 Barcode Font Example with Meaningful Human Readable Characters

Before the $M executes, the data entry screen would look as follows (but you wouldn't see it as it wouldn't stop before the Carriage Return was sent:

Full Ascii Code 39 Example 2

And finally, by just scanning a single barcode, you've eliminated all the key entry, or scanning of 2 seperate barcodes. The results are the same, with much less effort and chance for error on the part of the operator:

Full Ascii Code 39 Example 2

As part of this application, when you press the "PRINT" button on the bottom right side of the form, the order prints out and is handed to the customer. Each line contains a barcode for entry by the office clerk into Quickbooks. All the information is included in the barcode, including multiple tabs.

If you have any questions on how to use our fonts to accomplish exactly what you need to, don't hesitate to contact us by using this link: CLICK HERE!

When Not to Use Code 39

One of the arguments against the use of the Code 39 symbology barcodes is that ASCII characters take up too much space compared to Code 128 or other compact symbologies. With today's technology in laser printers and high density barcode scanners, this arguement goes away. Generally, you can just shrink the size if the font (and the barcode) so that it fits. The biggest argument for using Code 3 of 9 barcodes is that the characters are fixed bar-line relationships. This means that regardless of the other characters in the barcode, an "A" will always have the same number and thickness of white and black bars. It can therefore be represented in a barcode font. Code 128, UPC and other compact symbologies can't - they require complex calculations to generate the code, each character affecting the others and the total appearance of the barcode.

This is the compelling reason to "KEEP IT SIMPLE" by using Code 39 or Code 3 of 9 barcode fonts from Carolina Barcode!