KNX is an open standard that conforms to EN 50090 and ISO/IEC 14543. See KNX corresponds to the former European Installation Bus (EIB) and is backward-compatible.

With KNX technology, advanced multiple disciplines and simple solutions can be implemented to satisfy individual requirements in room and building automation in a flexible way. The ETS, a vendor-independent tool is available for commissioning.

KNX can use twisted pair cables, radio frequency (RF) or data transmission networks in connection with the Internet Protocol for communication between the devices. KNX has links and interfaces for connection to Ethernet/IP, RF, lighting control with DALI and building automation and control systems.


The following figure shows the structure of the KNX network:

  • KNX: KNX devices, e.g., third-party KNX
  • PX KNX: Automation station PXC001.D or PXC001-E.D and PX KNX firmware


A KNX network consists of lines. Up to 64 devices can be connected to each line.


Up to 15 lines can be connected to a main line via line couplers (LC). This is called an area.

Backbone line

The topology can be expanded by means of a backbone line. Up to 15 areas can be connected to the backbone line via backbone couplers (BC). Technically, these are the same devices as line couplers.

Line/Backbone couplers

Couplers separate the areas and lines. Couplers keep the bus traffic within bounds. Datagrams that are only needed on one line should not create a load on the entire network and hence have to be confined to that line. Respective filter tables are created (ETS) when setting up the project/network.

Engineering Tool Software (ETS)

The KNX Engineering Tool Software (ETS) is used to create KNX projects. A bus interface is required to commission the devices with ETS.

System Devices


The PX KNX system controller maps KNX devices to BACnet objects. PX KNX also supports different system functions, such as grouping, scheduling, alarming, trending, etc.

The system controller must be positioned correctly in relation to the topology and the load on the bus caused by the devices and connections (group addresses).

Bus power supply

Each line and each area must include a bus power supply.