Barcode Technology - Code 39 Barcode               Hide the description

Code 39 (also known as Alpha39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3) is a variable length,

discrete barcode symbology.

Valid characters:  0123456789[Space]ABCDEFGHIJKLMNOPQRSTUVWXYZ-.$/+%

Code 39 is one of the many barcode formats currently in use.

A Barcode is a method of representing data in a visual, machine-readable form.

The barcode formats has two categories:

One-dimensional (1D) --- Barcodes represented data by varying the widths and spacings of parallel lines.

Two-dimensional (2D) --- Using rectangles, dots, hexagons and other geometric patterns to represented data.

Code 39 can be to produced in different proportions: 2,0:1 and 3,0:1. This is the proportion between the thin and the

thick lines of the code. As higher the proportion, the wider is the printed barcode with same contents, but even better is readability.

The * character of Code 39:

The * character presented below is not a true encodable character, but is the start and stop symbol for Code 39. The asymmetry of the symbol allows the reader to determine the direction of the barcode being scanned. This code is traditionally mapped to the * character in barcode fonts and will often appear with the human-readable representation alongside the barcode.

In order to create this code do not have to enter the stars: If the text line shows *1234* you just have to enter 1234 because the stars are a fixed part of Code 39.

Check digit:

Since Code 39 is self-checking, a check digit normally isn't necessary. However, in applications that require an extremely high level of accuracy a modulo 43 checksum digit may be added.
To calculate the optional checksum digit, follow the following steps.
Take the value (0 through 42) of each character in the bar code. The start and stop characters are not included in the checksum calculation.
Sum the value of each of the values of each of the characters described in step 1.
Divide the result from step 2 by 43.
The remainder from the division in step 3 is the checksum character that will be appended to the data message before the stop character.

Drawback:

Possibly the most serious drawback of Code 39 is its low data density: It requires more space to encode data in Code 39 than, for example, in Code 128. This means that very small goods cannot be labeled with a Code 39 based barcode. However, Code 39 is still used by some postal services (although the Universal Postal Union recommends using Code 128 in all cases), and can be decoded with virtually any barcode reader. One advantage of Code 39 is that since there is no need to generate a check digit, it can easily be integrated into an existing printing system by adding a barcode font to the system or printer and then printing the raw data in that font.

Human Readable:

Most barcodes display their corresponding values below them, which makes it possible to human read and manually  enter the barcode values into the equivalent system when the barcode label is worn out and cannot be read by the barcode scanner.

Advantages:

If you want to reduce costs and save time, using barcodes is a good choice. Whether you are a company or a non-commercial organization, to improve efficiency and reduce overhead, barcodes are a valuable and viable option, which is economical and reliable.

Using Barcode system eliminates the possibility of human error. The error rate of manually entering data is
significantly higher than that of scan barcodes. Barcode scanning is fast and reliable, and it takes much less time than manual data entry. Especially when using a QR code, hundreds of characters can be read and entered into your system instantly.

History:

Code 39 was developed by Dr. David Allais and Ray Stevens of Intermec in 1974. Their original design included two wide bars and one wide space in each character, resulting in 40 possible characters. Setting aside one of these characters as a start and stop pattern left 39 characters, which was the origin of the name Code 39. Four punctuation characters were later added, using no wide bars and three wide spaces, expanding the character set to 43 characters.

FAQ About Code 39 Barcode

What is the historical origin of the Code 39 barcode?

Code 39 barcode is a barcode with no fixed length and can represent 43 characters, including uppercase Latin letters, numbers and some special characters.

The Code 39 barcode was developed by Dr. David Allier of Intermec in 1974 and was initially adopted by the U.S. Department of Defense as a military barcode.

The Code 39 barcode was the first alphanumeric barcode and was later widely used in industrial fields.

Because it could handle letters, CODE 39 was indispensable in the industrial field at the time and was used in factory automation industries such as automobiles and electronics.

Code 39 has only two unit widths, namely wide unit and narrow unit. The width of the wide unit is 1 to 3 times that of the narrow unit. Generally, 2 times, 2.5 times or 3 times are used. Each barcode character of Code 39 consists of nine units, three of which are wide units and the rest are narrow units, hence the name Code 39.

Code39 is one of the most widely used barcode formats. Code39 is defined in the ISO/IEC 16388:2007 standard.

LOGMARS stands for Logistics Applications of Automated Marking and Reading Symbols. It is defined by code 39 military standard MIL-STD-1189B.

What are the advantages and disadvantages of Code 39 barcodes?

Advantage:

Ability to encode data of any length. The limitations are the length of the printed matter and the recognition range of the barcode reader.

Supports a wide range of devices. At present, almost all barcode reading devices can read Code39 codes, and the same is true for printers.

Simple to Generate. Simple development techniques can quickly generate corresponding coded images.

Shortcoming:

The coding density is low and cannot represent complex characters such as Chinese. A check code is needed to improve reliability.

Comparison of Code128 barcode and Code39 barcode

Both Code128 barcodes and Code39 barcodes are widely used in corporate internal management, production processes, and logistics control systems. The difference is that the Code128 barcode represents more characters than the Code39 barcode, and the coding density per unit length is higher. When Code39 encoding cannot be accommodated in the unit length or the encoded characters exceed the limits of Code39, Code128 can be selected for encoding. So Code128 barcode is more flexible than Code39 barcode.

Code 128 barcodes can encode the full 128 ASCII character set, while Code 39 barcodes can only encode 39 characters.

The density of the Code 128 barcode is higher than that of the Code 39 barcode, which means that for the same length of barcode, Code 128 can represent more information.

Code 128 barcodes contain check digits, while Code 39 barcodes do not, which means Code 128 barcodes are more reliable.

Code39 and Code128 are representatives of one-dimensional barcodes, and they are also widely used in the industry. For product numbers, serial numbers, network card addresses and IMEI numbers on mobile phones, cameras or 3C products, Code39 and Code128 are mostly used. A barcode encoding method.

The difference between Code 39 barcode and Code 39ext

The Code 39Ext barcode is an extended version of the Code 39 barcode and can represent 128 characters from ASCII values 0 to 127.

Code 39 barcodes can only encode 43 characters, including numbers, uppercase letters, spaces, and some symbols.
Code 39ext can encode 128 characters, including lowercase letters and some special symbols.

The encoding rule of Code 39ext is to add an escape character before each character, for example, %U represents the lowercase letter u.

Code 39 encoding rules

Every fifth line represents a character.

Thick lines represent 1, thin lines represent 0.

A wide gap between lines represents 1, and a narrow gap represents 0.

Five lines plus four gaps between them is a nine-digit binary code, and three of these nine digits must be 1, so it is called 39 codes.

A * at the beginning and end of the barcode marks the beginning and end.

Will Code 39 barcodes be phased out?

Code 39 barcode is a commonly used one-dimensional barcode format. It can encode data of any length and supports a wide range of devices. However, it also has some shortcomings, such as low encoding efficiency and inability to represent Chinese. At present, the Code 39 barcode has not been eliminated, but with the development of two-dimensional barcodes, it may be gradually replaced.

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