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KNX RF integration

KNX RF, short for KNX Radio Frequency, is a wireless communication technology used in building automation systems. It is based on the international standard ISO/IEC 14543-3-10 and operates in the 868 MHz frequency band in Europe and 902 MHz in North America. KNX RF is designed for use in applications where wired communication is not feasible or desirable, such as in historic buildings or outdoor areas. It provides a reliable and secure wireless connection between KNX devices, allowing them to exchange data and control signals.

KNX RF Devices:

KNX RF devices are typically used in applications where it is not possible or practical to install wired KNX devices. For example, KNX RF devices can be used in historic buildings where it is not possible to run new wires, or in outdoor applications where it is not practical to bury cables.

KNX RF devices are available in a variety of form factors, including switches, dimmers, thermostats, and motion sensors. KNX RF devices can also be used to control devices that are not directly connected to the KNX network, such as IR devices or ZigBee devices.


KNX RF actuators are available in a variety of form factors, including plug-in modules, wall-mounted switches, and DIN-rail mounted devices. They can also be used with a variety of electrical devices, including lights, blinds, fans, and pumps.


KNX RF dimmers are a convenient and energy-efficient way to control the lighting in your home. They can help you to save energy by dimming the lights when they are not in use, and they can also make it easier to create the perfect lighting ambiance for any occasion.


KNX RF sensors come in various types, including temperature sensors, humidity sensors, motion detectors, and window/door contacts. These sensors collect data about their respective environmental conditions and transmit it wirelessly to the KNX network. The data can then be processed by a central controller or gateway, which can take appropriate actions based on the sensor readings.

Controllers / Gateway:

KNX RF controllers are devices that allow you to control KNX devices wirelessly. They are typically used in conjunction with a KNX gateway, which is a device that connects the KNX network to the Internet. KNX RF controllers can be used to control a variety of devices, including lights, thermostats, and blinds.


KNX RF keypad is a device that allows users to control KNX smart home systems wirelessly. It typically consists of a series of buttons or touch-sensitive areas that can be programmed to perform various functions, such as turning on/off lights, adjusting thermostats, or controlling blinds. KNX RF keypads are often used in conjunction with other KNX devices, such as sensors and actuators, to create a fully automated smart home system.

Programming Interface

The KNX RF USB interface allows you to connect your computer to a KNX network without the need for a separate power supply. It also provides a convenient way to program and configure KNX devices.

Now, lets understand the KNX RF (Radio Frequency) wireless connectivity for the automation system.

KNX RF (Radio Frequency):

Radio Frequency is one of the type of communication medium in the KNX standard for home and building automation. KNX RF allows for wireless communication between KNX devices like Gateways, Switches, Dimmers, Couplers, Interface, Sensors. KNX RF suitable in installations where wired connections are difficult or feasibility of wiring is not possible. The delay in RF system of KNX is very much low, human cannot noticed it even in time-critical sensors such as buttons. The RF system is very useful when you are extending old KNX based wired system OR you have not wiring for the centralized KNX system available in home or building. A wide range of flush mounted devices such as Switches, Dimmers, Blind or heating actuators, Gateways, Couplers, Keypads is available for this purpose. There is also an RF button interface for the integration of buttons or temperature sensors. Below are some KNX RF features.

Wireless Communication:

KNX RF enables wireless communication between KNX devices. KNX RF enabled devices exchange information and control signals without the need for physical wiring. KNX RF devices are typically battery-powered, making them suitable for applications where wiring is impractical or cost-prohibitive. They also have low power consumption, ensuring long battery life.

Radio Frequency Bands:

KNX RF operates on different bands by region. Operates on 868 MHz frequency band in the Europe and other regions where this frequency is allocated for short-range devices. In the United States, it operates in the 902-928 MHz frequency band. With SRD frequency band (Short Range Device), which also has a relatively small range due to its particularly low output power. It therefore has a high electromagnetic compatibility and does not interfere with other systems. KNX RF has a transmission power of 0.5-25 mW.

Mesh Networking and benefits:

KNX RF devices can create a mesh network, where each device acts as a node that can transmit and receive signals over RF. Mesh networking capability enhances the reliability and coverage of the wireless communication within the KNX system. Each transmitter has the LBT function ( Listen Before Talk). This avoids radio collisions as far as possible.


KNX RF devices are designed to communicate with other KNX devices, regardless of any communication medium used. Due to this compatibility KNX installations can include both wired and wireless components seamlessly.


KNX RF is suitable for various applications within building automation, like lighting control, curtain, heating, ventilation, air conditioning (HVAC), security systems, and more. It provides a wireless solution for projects where wired connections may be difficult.

Integration with KNX TP:

In many KNX installations, KNX RF is used in conjunction with KNX TP (Twisted Pair) for a hybrid wired and wireless solution. This integration allows for more flexibility in manner the specific needs of different areas within a building.

KNX RF Topology:

The KNX RF media coupler is the interface between wired and radio-based (RF) communication. The media coupler works like a conventional range/line/area coupler and also has filter settings. The corresponding filter tables are loaded by the ETS when programming the application. In this way, the media coupler forwards only the required telegrams between TP-RF and vice versa. This is also important with regard to the telegram traffic on the RF side. It is important to keep this as low as possible in order to minimize problems caused by telegram collisions.

RF Media Coupler AS Line Coupler:

Further lines can be set up with TP line couplers or RF media couplers Each line may only contain 1 media coupler (unless the media coupler is configured as a repeater)

RF Media Coupler AS Area Coupler:

If the media coupler is to work as an area coupler, a backbone with media type TP is absolutely necessary Each area may only contain 1 media coupler (unless the media coupler is configured as a repeater)

What to consider while setup of KNX RF?

  • Place the media coupler as centrally as possible in the reception area of all RF participants.
  • In small RF installations, RF devices as repeaters are preferable to several media couplers. Repeaters should be located in the reception area of each other. The repeater mode should only be activated for needed devices in order to keep the number of repeated RF telegrams as low as possible.
  • Multiple media couplers or RF lines should only be used if the radio ranges are congruent with each other or strictly separated. If the different RF lines only intersect with each other in the reception area, communication problems due to overlapping telegrams may occur.
  • Due to the nature of the protocol (LBT and lack of acknowledgement of receipt), we recommend using KNX RF as a supplement to TP systems for setting up room, island, and extension solutions. The practical maximum size depends on the building condition, the placement of the devices as well as the telegram volume.
  • Since the media coupler has the filter characteristics of a line coupler, the media coupler must usually also be reprogrammed after changes to other RF devices.

ETS and RF Tools

ETS works as the all-purpose tool, able to configure KNX-RF devices not only via TP/RF media couplers, but also directly thanks to the USB-RF. device. KNX RF devices are easily spotted in the Online Catalog, are added to the project like any other device.

Some KNX Partners working with KNX RF devices is the availability of specific Apps for RF device management: it is possible checking the signal strength between RF devices in a visual way, which allows the system integrator placing re-transmitters (when necessary) in the most optimal position, commission devices knowing the signal strength, etc.

KNX RF devices, as KNX TP devices, can offer different programming modes:

KNX RF S-Mode (System Mode) devices require a computer with the tool ETS to be configured.

  • Devices contain (individual) Group Objects
  • Devices are linked by manually assigning Group Addresses to Group Objects, via ETS

KNX RF E-Mode (Easy Mode) devices can be configured without the need of a computer (i.e. push buttons, specific controller…).

  • Devices contain E-Mode Channels
  • Devices are linked by automatically assigning Group Addresses to E-Mode Channels
  • Linking is based on connection codes, one per Group Object


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