Basic knowledge of barcode scanner

Barcode scanners are usually called barcode scanners/readers. They are devices used to read the information contained in barcodes. They can be divided into one-dimensional and two-dimensional barcode scanners. The structure of a barcode scanner usually consists of the following parts: light source, receiving device, photoelectric conversion component, decoding circuit, and computer interface. The basic working principle of the scanning gun is: the light emitted by the light source illuminates the bar code symbol through the optical system. The reflected light is imaged on the photoelectric converter through the optical system, and interpreted as a digital signal that the computer can directly accept by the decoder. Except for the classification of one and two-dimensional barcode scanners. It can also be classified as: CCD, full-angle laser and laser handheld barcode scanner. The following article explains the basic knowledge of the scanner and some of the daily use problems.

1. How to use a barcode scanner to scan?
First check the power supply of the barcode scanner: external power supply or PC host power supply. If it is powered by a PC host, check the interface mode of the barcode scanner, such as USB port, keyboard port, serial port, etc. If it is a USB port, you can directly plug it into the host. If it is an RS-232 port or a serial port, you need to turn off the host, and then Connect the cable of the barcode scanner, and then turn on the PC. Then read the manual of the barcode scanner, and set by scanning the barcode on the user manual. After the setting is completed, you can scan and upload the data to the computer.
2. What is depth of field?
Depth of field refers to the distance between the closest point and the farthest point of the barcode barcode scanner can scan.
3. What is the difference between RS-232 port and keyboard port?
The main difference between commonly used interfaces is the way they send data to the terminal. The keyboard port is a device that connects the keyboard and the terminal. When the keyboard port is used, the barcode symbol is regarded as the data sent by the keyboard by the terminal. At the same time, the keyboard port of the terminal can continue to function. RS-232 is used to connect the serial port of the host or terminal to send serial data to the computer. Because serial communication requires a certain protocol, the device using RS-232 must specify the baud rate (data transfer rate) and data bits And the parity bit.
4. How to know the symbology of scanned barcodes?
You can refer to the user manual of the barcode scanner. In the parameter part of the barcode output or add the prefix and suffix part, this function will add a prefix character before the barcode character, which represents the type of barcode read. Confirm, such as: "b" stands for 39 code, "c" stands for UPC code, etc. The specific situation depends on whether the scanner provides this support.
5. How to upgrade the decoding software of the barcode reader?
Contact the corresponding manufacturer to find the upgrade program or send it back to the manufacturer for upgrade
6. What is the maximum length of the barcode scanner cable?
The RS-232 length standard established by the Federation of Electronics Industries is 15 meters long. Typical RS-232 cable lengths for HHP barcode readers are 2.75 meters and 4.7 meters; the cable length for light pen simulation is 2.1 meters or 4.5 meters; HHLC cable The length is 2.1, 4.5 or 6.7 meters; the length of the OCIA cable is determined by the type of terminal and can be customized to the factory; the length of the keyboard cable is usually 2.7 meters, and the 4.7-meter keyboard cable needs an external power supply.
7. Several reasons why the barcode scanner cannot read the barcode:
1) The function of reading this bar code is not turned on. (There are many barcode rules, the general barcode scanner can only recognize several common barcodes unless specifically required).
2) The bar code does not meet the specifications, such as lack of necessary blank areas, the contrast between bars and spaces is too low, and the width and narrow ratio of bars and spaces is inappropriate.
3) In direct sunlight, the photosensitive device enters the saturation zone.
4) The surface of the barcode is covered with transparent material, and the reflectivity is too high. Although the barcode can be seen by the eyes, the reading condition of the collector is strict and cannot be read.
5) The connection line is loose and there is no power supply, so it cannot scan.
6) Hardware failure, contact your dealer for repair.