Early alarm systems mainly used wired telephone systems to report cases after they occurred. The police department dispatched personnel to the scene to conduct investigations, analyze and study the case, and organize the resolution of the case. This kind of work procedure is mostly for post processing. Due to the insufficient network of the wired telephone system at that time, the phenomenon of “busy lines” often occurred, so it also delayed a lot of the best time to solve the case.

With the development of communication technology, wireless positioning technology, and computer management technology, a wireless network alarm system that uses low-frequency wireless information positioning and transmits information to computers for processing has been launched internationally. Therefore, wireless network alarm systems can quickly determine the location and basic nature of the case at the first time of the incident, which has gained valuable time for preventing the expansion and development of the case in advance, and is therefore widely popular in the market.

1 Composition of the network alarm system

Traditional alarm systems are composed of three parts: front-end detectors, detection signal transmission, and alarm control panels.

Nowadays, the network alarm system combines the detector and alarm control panel as the front-end part, and the transmission part from the alarm control panel to the alarm receiving centre is called the transmission part, while the alarm receiving centre is called the back-end management platform part.

2 The shortcomings of the traditional PSTN communication method

For the large-scale regional network alarm system, the traditional PSTN communication method has become increasingly inadequate. Due to the need to establish an actual voice dialing physical connection before communication, the time is relatively long, and it takes more than 10 seconds, or even nearly 20 seconds, to complete a report. There is a risk that alarm signals cannot be delivered to the alarm receiving centre in a timely manner, especially for users who cross multiple regions and large-scale PSTN networks, the risk will be even greater. In addition to slow speed, PSTN based network alarm system has other inherent drawbacks, and traditional telephone alarms are one-way communication, with the alarm receiving centre only passively receiving information reported by the front-end alarm control panel.

3 The advantages of network alarm

In addition to receiving information reported by the front-end, the alarm receiving centre can also access front-end devices. The traditional PSTN alarm method, if there is a fault in the line, the alarm receiving centre cannot know whether the front-end alarm control panel is online or disconnected, and it is difficult for the alarm receiving centre to detect. Once the network alarm transmission fails, the alarm receiving centre will immediately display it. Moreover, the traditional PSTN alarm method often receives unknown information from the alarm receiving centre, which is related to line noise and faults. However, network alarm methods can greatly improve transmission quality and the reliability of alarm systems.

4 The functions of the wireless network alarm system

The most essential requirement for network alarm system is to be able to quickly and in real-time report to the alarm receiving centre after an alarm occurs. Therefore, wireless alarm devices should also take this as the foundation and leverage their advantages in wireless alarm. In places with wired PSTN or IP networks, wireless transmission can serve as a backup network alarm transmission method. In places without PSTN and IP networks, wireless transmission must be used as an important network alarm transmission method.

The functions of the wireless network alarm system can be summarized as follows:

(1) Monitoring of PSTN and IP networks: When the wireless alarm device is connected to the wired alarm control panel, it should be able to detect the status of the wired transmission network without interfering with the original wired transmission network. Once it is found that the wired network cannot be used normally, it will automatically take over the original wired alarm channel and switch to wireless alarm mode. Of course, if there is no PSTN or IP network at all, switch directly to wireless alarm mode to complete the alarm function.

(2) Sending of alarm information: The wireless alarm module itself can send alarm signals, such as sending a disconnection alarm when a telephone line fault is detected. The wireless alarm module can also receive alarm information from the connected alarm host and send it out in real time.

(3) The sending format of alarm information: To ensure compatibility with the existing alarm receiving centre, the sending format of wireless alarm devices must comply with the requirements of the alarm receiving centre.

(4) Embedded installation: As the network alarm system has been built, the wireless network alarm system must be compatible with various alarm control panels that are already on the network, and the wireless transmission module must also be embedded into the alarm control panel.

5 The popularization of the wireless network alarm system

Advanced technology has always been constantly evolving. In intrusion alarm systems, IP wired network alarm methods are flourishing, 4G and 5G wireless communication technology will open up a new era of wireless network alarm. In addition to wired PSTN and IP networks, 4G and 5G wireless communication technologies will undoubtedly become the focus of attention in the security industry. Due to the convenience of installation and maintenance, the wireless network alarm system currently occupies an increasing share in the entire intrusion alarm system. It has gradually been widely used in home security and small commercial alarm systems.