KNX Stack – Medium RF

Radio Frequency RF is the wireless solution in the KNX standard. KNX RF was, until recently, only used with the Easy Mode like the Easy Push Button Mode. With the introduction of the ETS5 there will be S-Mode Support for KNX RF.

With the new ETS5, released in October 2015, wireless devices can be configured in the same professional manner as TP-connected products. This important step in the evolution of the KNX standard has been carried out under the working title “KNX RF +”, while the official name is now KNX RF S-Mode. S mode stands for system mode and means the configuration with the ETS software of the KNX Association. KNX RF uses frequency shift keying (FSK) for the data modulation frequency with a center frequency of 868.3 MHz. With data rates of 16384 baud, a similar number of frames can be transmitted as with TP. The physical layer of KNX-RF corresponds to the Wireless M-Bus (DIN EN 13757-4, S mode).

The new KNX-RF standard distinguishes between (real) bidirectional and semi-directional devices, which are bi-directional and unidirectional in normal operation. The HF transceiver of these semi-directional devices does not always have to be switched on, so these devices come with very low power consumption and are suitable for battery-powered applications.