Transmission characteristics and feature analysis of security wireless modules

The wireless module is a module that uses wireless technology for wireless transmission. It is widely used in computer wireless networks, wireless communications, wireless control and other fields. What are its characteristics and features?

1. Micro-transmission power. Different transmission intervals have different transmission powers, ranging from 10mW to 100mW. The PTZ generally uses a 220V civilian AC power supply, which is converted into a usable DC power supply internally. The wireless data transmission modules of the JZ871 and JZ872 series generally use a 3~5V DC voltage, which has very low power consumption, so it has the characteristics of power saving.

2. ISM band operating frequency, no need to apply for frequency points. Carrier frequency 429-438MHz.

3. High anti-interference ability and low bit error rate. Based on the GFSK modulation method, an efficient communication protocol is adopted. When the channel bit error rate is 10-2, the actual bit error rate can be obtained. 10-5~10-6. The transmission protocol of the PTZ is generally very simple, and the data packet is very short. At the same time, the last Byte is generally the check bit, which has the ability to correct errors. In view of the intermittent communication and small data packet transmission characteristics of the PTZ, the application of wireless modules has good maneuverability.

4. Long transmission interval. The open interval ranges from 300 meters to 10 kilometers. In the case of internal testing of JZ878, the open interval can reach a transmission interval of 8~20km. In actual buildings, it can penetrate at least multiple 12-story reinforced concrete buildings, which can well meet the working environment and requirements of the PTZ.

5. Transparent data transmission. What is sent is what is received. The PTZ control has its own protocol, and the wireless module does not make any modifications or analysis to the transmitted data packets, so the communication between the PTZ and the console does not need to modify any code due to the existence of the wireless data transmission module. When the hardware communication is unobstructed, the software can be executed correctly without any modification.

6. Multi-channel, multi-rate. Provides 16 channels, which can be expanded to 32 channels according to user needs to meet the needs of users for multiple communication combinations. The actual monitoring system uses different numbers of PTZs. If there are more than 100 PTZs and the number of PTZs controlled at the same time is relatively large, the PTZs can be grouped and each group uses different channels for communication to avoid data packet conflicts and ensure the timeliness of communication. The wireless module can provide a variety of communication baud rates from 1200bps to 38400bps, and the wireless transmission rate is proportional to the interface baud rate to meet the needs of customer equipment for multiple baud rates. The baud rate of the PTZ is generally 9600, but other baud rates are also used. The rate range of the wireless module can fully meet the requirements of the PTZ.

7. Provide three interface modes: RS232/485/TTL. The working PTZ generally does not want to be rearranged. At this time, the wireless module needs to adapt to this situation. The current interface mode of the PTZ is generally RS232 or 485, or both are supported, so the wireless module can adapt to the interface mode of the PTZ well and can work without changing the hardware of the PTZ.

8. Intelligent data control, users do not need to compile redundant programs. Maximize the reusability of most serial port operation codes. For the software of the monitoring system, the wireless transmission method is exactly the same as the original wired transmission method. You only need to add a wireless module to the hardware and remove all wired lines and equipment. The operation is also very simple. Basically, you just need to connect the wireless module to the host and slave computers.

9. High reliability, small size and light weight. It uses a high-performance single-chip processor ATMega8L, with few peripheral circuits, high reliability and low failure rate. The size of the wireless module is similar to a matchbox. Such a size will not cause difficulties in the transformation of the original system. Even some capable PTZ manufacturers can embed the wireless data transmission module into the PTZ, making the product more competitive.

10. Watchdog real-time monitoring. In the case of power failure, power surge, external interference, and system debugging, the wireless module will not have any problems. It can work as long as it is powered on. It is safe, reliable and stable.

In summary, due to the characteristics and features of the wireless module, the software control part of the PTZ can be put into use without modification, and no special processing is required on the hardware. You only need to connect the communication line to the wireless module. In the RS232 interface mode, the GND, RXD, TXD of the PTZ and the control end need to be connected to the corresponding interface of the wireless module. In the RS485 mode, you only need to connect A, B to A, B of the wireless module. Even if one end uses 485 and the other end uses 232, normal communication can still be achieved. Finally, set up the wireless module correctly and connect it to the power supply, and it can be put into use. It can be applied to the installation of new systems, as well as the modification and upgrade of existing systems.