1D Barcodes
Nov 29, 2018

The one-dimensional bar code refers to the bar code and the empty arrangement rule. The code system of the commonly used 1d barcodes includes: EAN 13,  code 39, UPC A, Interleaved 2 of 5 code128,  code 93, ISBN , and Codabar etc.

Barcodes originated in the 1940s and were used in the 1970s and got popularized in the 1980s. Barcode technology is an automatic identification technology widely used in computer applications and practice, which is widely used in business, postal, library management, warehousing, industrial production process control, transportation, etc. It has fast input speed and high accuracy. The advantages of low cost and high reliability play an important role in today's automatic identification technology.

A bar code is a tag consisting of a set of regularly arranged bars, spaces, and corresponding characters. A "bar" refers to a portion with a low reflectance to light, and "empty" refers to a portion with a high reflectance to light, and these bars and spaces constitute a portion. The data expresses certain information and can be read by a specific device and converted into binary and decimal information compatible with the computer. Usually for each item, its encoding is unique. For ordinary one-dimensional barcodes, the correspondence between barcodes and product information is also established through the database. When the barcode data is transmitted to the computer, it is used by the computer. The application operates and processes the data. Therefore, the ordinary one-dimensional bar code is only used as identification information in the course of use, and its meaning is realized by extracting corresponding information in the database of the computer system. One-dimensional barcodes are simple to make, and the code system is easier to obtain and falsify by criminals. Second, one-dimensional barcodes are almost impossible to represent Chinese characters and image information.

Since objects of different colors have different wavelengths of visible light, white objects can reflect visible light of various wavelengths, and black objects absorb visible light of various wavelengths. Therefore, when the light emitted by the bar code scanner light passes through the aperture and the convex lens 1, When irradiated onto the black and white bar code, the reflected light is focused by the convex lens 2, and then irradiated onto the photoelectric converter, so that the photoelectric converter receives the reflected light signals different in intensity from the white bars and the black bars, and converts them into corresponding The electrical signal is output to the amplification shaping circuit. The width of the white strip and the black strip are different, and the duration of the corresponding electrical signal is also different. However, the electrical signal corresponding to the bar code and the space of the bar code output by the photoelectric converter is generally only about 10 mV, and cannot be directly used. Therefore, the electric signal output from the photoelectric converter is first sent to the amplifier for amplification. The amplified electrical signal is still an analog electrical signal. In order to avoid the error signal caused by defects and stains in the barcode, an shaping circuit is needed after the amplifying circuit to convert the analog signal into a digital electrical signal so that the computer system can accurately interpret the signal. .

The pulsed digital signal of the shaping circuit is translated into digital and character information by the decoder. It identifies the code system and scanning direction of the bar code symbol by identifying the start and end characters; it determines the number of bars and spaces by measuring the number of pulse digital electrical signals 0, 1. Determine the width of the strip and the space by measuring the duration of the 0 and 1 signals. In this way, the number of bars and spaces of the bar code symbols to be read and the corresponding width and the code system used are obtained. According to the coding rules corresponding to the code system, the bar symbols can be replaced with corresponding numbers and character information. The interface circuit is sent to the computer system for data processing and management, and the whole process of one-dimensional bar code reading is completed.

All kinds of barcode scanner can decode 1D barcodes which include laser barcode scanner ,linear image barcode scanner ,and it is most used in logistics ,supermarket merchandise labels and health care industries.with the developing of 2D barcodes , it replace 1D barcodes in some industries such as logistics bill . for now logistic bills use QR code to record more info than 1D barcodes,which it contains consignee,shipper ,address ,contacts etc .it is very quick to pick up goods ,the man just need to scan the QR code in the bill ,then everything he will know this cargo where to delivery and the contact details .

But the 1D barcodes still in dominant position in the markets ,so still need 1D barcode scanners to decode it , syble is a China supplier of barcode scanner which ship to clients over the world .


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