Communication protocol (standard) used by the wireless format sensor (see “Connection”).
This parameter directly affects compatibility - the equipment with which the sensor is used must support the same protocol, otherwise normal operation will not be possible. As for specific options, modern sensors can use both common standards
Wi-Fi and
Bluetooth, as well as specialized protocols - most often
Z-Wave,
Zigbee,
Jeweler or
Fibra. Sensors can also operate at
their own frequency. Here is a more detailed description of each of these standards:
- Wi-Fi. A technology used primarily for building wireless computer networks, and more recently also for direct communication between individual devices. For communications, the 2.4 GHz or 5 GHz band is most often used. In the case of wireless sensors, one of the advantages of Wi-Fi is that it is a widely accepted standard; thanks to this, many sensors with this type of communication can work without special equipment - they are able to connect to ordinary wireless routers or even individual devices such as laptops and tablets (some models even allow sending notifications via the Internet, through the same router). However, this versatility also has a downside: Wi-Fi does not have ad
...ditional optimization for working with wireless sensors. As a result, such communication is inferior to specialized protocols in terms of overall reliability, special functionality and energy efficiency. So this type of communication is typical mainly for devices designed for simple conditions of use - such as climate temperature/humidity sensors for smart home systems.
— Bluetooth. Another commonly used wireless communication standard. Operates in the 2.4 GHz band; Unlike Wi-Fi, it is used only for direct communication between devices. It is also poorly suited for professional use (in particular, the response delay can reach 2–3 seconds), and therefore is found mainly in household sensors designed for communication to smartphones/tablets or smart home systems. The most commonly used protocol for communication is Bluetooth LE, supported by Bluetooth modules version 4.0 and higher: it is specially designed for miniature devices with small built-in batteries, allows data transfer with very low energy costs and at the same time provides a range of up to 100 m.
- Z-Wave. Communication protocol developed specifically for automation and remote control systems. Provides for the transmission of the simplest and shortest control commands with minimal delays; Communication uses a range of up to 1 GHz, making such communication virtually immune to interference from Wi-Fi and Bluetooth devices located nearby. Another interesting feature of Z-Wave is the use of a MESH type topology. The signal from a sensor in such a network can be transmitted to the control device either directly or through any number of intermediate nodes, and the optimal route is determined taking into account the current situation: for example, if one of the nodes on the shortest signal path fails, the information will go “to bypass", through other repeaters within range. However, it is worth noting that MESH relay significantly increases energy consumption, so Z-Wave nodes powered by batteries/accumulators do not perform it.
- Zigbee. Another communication protocol created for automation systems (including smart home), alarms, industrial control, etc. Optimized for secure data transfer at low speeds and with minimal power consumption acceptable for miniature battery-powered devices. Just like the Z-Wave described above, it uses a MESH network topology, with the ability to transmit a signal through several nodes and automatically select the optimal route taking into account the current situation in the network. It is distinguished by good protection and noise immunity, as well as a high response speed (recovery from sleep mode takes about 15 milliseconds), due to which it is quite widely used in modern wireless sensors.
— Jeweler. Ajax Systems' own development, a communication protocol created specifically for protection systems - this is its fundamental difference from the standards described above. The creators declared such advantages as long range (up to 2000 m), high response speed (0.15 ms), low power consumption (up to 7 years of continuous operation in some sensor models), support for several frequencies (with automatic switching when the level of interference or jamming attempt), an advanced system of protection against failures and interference (with high-quality encryption, precise detection of the type of attack and the sensor being hacked, as well as notification of jamming), as well as the ability to operate up to 150 devices on one hub. Among the obvious disadvantages, one can note only its limited use: Jeweler is supported only by devices from Ajax Systems (at least for now). However, special integration modules are produced that allow connecting such sensors to wired and wireless control panels from other manufacturers.
— Fibra. The Fibra wired communication protocol was created by Ajax System specifically for protection systems. The technology inherits the wireless capabilities of the related Jeweler protocol (see above), but all devices are connected using a traditional four-wire cable. One Fibra line up to 2000 m long can connect one sensor or several dozen (together with sirens and keyboards in any combination). The digital architecture when using the Fibra communication protocol is built in the proprietary Ajax PRO application. The transmitted data is protected using floating key encryption, and Fibra communication is organized according to the TDMA principle: each device is allocated a short period of time to exchange data with the hub. The rest of the time, communication modules remain inactive, which significantly reduces power consumption and helps avoid conflicts even when several sensors are triggered simultaneously. Fibra is supported in hardware only by devices from Ajax Systems, however, there are special integration modules that allow you to connect such sensors to wired control panels from other manufacturers.
— Natural frequency. In the context of protection sensors, this parameter refers to the natural frequency at which wireless data exchange is ensured between parts of the protection system. Its specific value is determined by the device manufacturer, but the most common options are 433 - 434 MHz and 868 MHz. Using a natural frequency improves the reliability and protection of the protection system because it reduces the likelihood of interference from other wireless devices operating at similar frequencies. When choosing based on this parameter, it is important to consider equipment compatibility, standards and licensing requirements (in order to avoid potential violations of the law).Operating time of the self-powered sensor on one set of batteries or battery charge (see "Power"). Note that this indicator is quite approximate — it is usually indicated either for an perfect or for a certain “average” mode of operation. The real battery life also depends on a number of practical nuances: the frequency of operations, the communication range, the level of interference, etc., up to the air temperature. So in fact, the operating time may differ from the claimed one, and in the other direction. Nevertheless, according to this characteristic, it is quite possible to both evaluate the overall battery life of the sensor and compare different models with each other: the difference in the indicated operating time usually fully corresponds to the difference in real battery life.
Note that modern sensors have very low power consumption, so their operating time is calculated in months.
