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With the improvement of people’s lives and the acceleration of their pace of life, people have put forward higher requirements on the living environment, methods, and rhythm. The emergence of barcode scanners undoubtedly brought great convenience to people in many aspects, such as: Warehouse management, cash register, records, etc., save people a lot of trouble. However, the traditional barcode scanner always has a cable to connect to the data terminal (PC), which makes the range of movement of the scanner is very limited, and the activities are very limited, and the number of scanners connected to a data terminal is also very limited. , Which makes the data terminal equipment resources very wasteful, these and so on have given the scanning gun a revolutionary challenge. The emergence of wireless scanning guns has supplemented a series of weaknesses of traditional wired scanning guns.
Based on daily needs, the company developed a wireless scanning gun and its networking system using a wireless data transmission module independently developed by the company.
There are roughly two communication methods for wireless scanners: one-to-one communication and one-to-many communication.
One, one-to-one communication
The so-called one-to-one communication means that one sending end corresponds to one receiving end, and the two data terminals are in one-to-one correspondence, so that multiple one-to-one communications can be formed. Because the wireless module developed by our company has the functions of autonomous channel preemption and avoidance , So it will not involve the problem of co-channel interference, because only one is sending data at any time. Another solution is to use a polling method to name each wireless sender point by point to send data (this solution is for wireless modules that do not have autonomous preemption and avoidance functions).
Figure 1 shows a one-to-one wireless scanning system with only one scanning gun and one data receiving terminal. This solution is simple and reliable, without any communication protocol, but the system capacity is small, only suitable for small occasions with only one scanning gun.
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figure 1
As shown in Figure 2, there are multiple one-to-one scanning systems. This system requires the module to have autonomous channel occupation and avoidance functions, and the wireless device on the scanning end and the wireless device on the receiving end must have an address correspondence to identify the source and the source of the data. take over. Each data receiving end only receives the data sent by the wireless scanning gun of its corresponding address. This system is more complicated than the system shown in Figure 1, but each wireless scanning gun and its corresponding data terminal is an independent unit. If a group of units fails, it will not have a negative impact on the other units.
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figure 2
Figure 3 shows multiple one-to-one scanning systems in the polling mode. This communication mode is designed for wireless modules without autonomous channel preemption and avoidance functions. This system is better than the system shown in Figure 2. There is one more polling controller, and its data transmission method is the same, except that the timing of the wireless scanning gun to send data wirelessly is different. As long as the wireless of the system shown in Figure 2 detects that no other wireless devices with the same signal are sending data, the wireless The device sends the stored data. However, the system shown in Figure 3 sends data when the polling controller polls whoever is polled, and does not involve the problem of channel occupation.
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image 3
Two, one-to-many communication
The so-called one-to-many communication method means that multiple wireless devices are sending data and only one receiving end is receiving. This kind of system can also be divided into two ways according to the functional characteristics of the wireless module. One is self-preemption signal transmission, and the other is the receiving end polling and controlling the sending end to send, and finally all are received by a receiving end. As shown in Figure 4:
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Figure 4
Three, the characteristics of the wireless scanning system
1. Easy to install, simple, low cost, easy to maintain
2. Data adopts verification, high reliability
3. It is convenient to drive, flexible, and has a large range of activities without being restricted by connecting wires.
4. The appropriate system can be selected according to the occasion
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