Gira 5110 00 Product Documentation page 17

Different RF domains in one KNX installation
Devices in different RF domains must be topologically divided into two different lines or
backbones, each with their own domain addresses. These different areas or lines must also
contain their own media couplers for the devices to be able to communicate with one another,
irrespective of the line. The logical connection between two or more KNX RF environments is
thus always made via media couplers and higher-level TP or IP lines (Figure 4).
KNX RF USB data interfaces, as used in the ETS, are also assigned to a domain address. In
consequence, only RF devices of the same domain can be commissioned directly by radio
telegram. Only group telegrams and physically addressed telegrams of the appropriate RF
domain are recorded in the group monitor of the ETS (exception: 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 necessary. 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).
Figure 4: Example of a possible KNX topology with two RF lines
i 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, radio 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).
i Media couplers cannot be used to network two or more KNX installations via RF (no proxy
function)!
Order No. 5110 00
and coupling via a TP main line (example)
Software "Media coupler / repeater"
Functional description
Page 17 of 57