Function | Function as media coupler
RF/TP media coupler/repeater | Order no. 5110 00 | 51103300
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of the appropriate RF domain are recorded in the group monitor of the ETS (excep-
tion: System broadcast telegrams). If other RF devices of another domain are to be
contacted with an RF data interface, then communication via media couplers is ne-
cessary. If the KNX topology is set up correctly, then such communication takes
place automatically via the KNX routing (precondition: media and backbone/line
couplers forward the telegrams according to their filter property).
Image 5: Example of a possible KNX topology with two RF lines and coupling via a
main TP line
In general, multiple media couplers can be used in various lines and areas of a
KNX topology. The ETS permits such a configuration. However, media
couplers in a shared KNX system can influence each other unfavourably. In
particular, during the commissioning of various bus devices using the ETS, ra-
dio telegrams may be superimposed, meaning that radio communication is
poor or even impossible. Suitable precautions can be taken to avoid such a
situation (spatial separation of the RF environments, logical filtering of specific
telegrams).
Media couplers cannot be used to network two or more KNX installations via
RF (no proxy function)!
RF areas or lines of a joint KNX installation or of directly adjacent KNX install-
ations in radio range may never have an identical domain address! The ETS
offers a function for random assignment of a domain address for RF lines, in
order to avoid this improper situation. When the random function is used, the
