KNX defines several physical communication media:
- Twisted pair wiring (inherited from the BatiBUS and EIB Instabus standards)
- Powerline networking (inherited from EIB and EHS – similar to that used by X10)
- Radio (KNX-RF)
- Ethernet (also known as EIBnet/IP or KNXnet/IP)
KNX is designed to be independent of any particular hardware platform. A KNX Device Network can be controlled by anything from an 8-bit microcontroller to a PC, according to the needs of a particular implementation. The most common form of installation is over twisted pair medium.
KNX is approved as an open standard to:
- International standard (ISO/IEC 14543-3)
- Canadian standard (CSA-ISO/IEC 14543-3)
- European Standard (CENELEC EN 50090 and CEN EN 13321-1)
- China Guo Biao (GB/T 20965)
KNX Association, as of 1 March 2014, had 339 members/manufacturers from 37 countries. Japan’s Fujitsu General was enlisted as member number 300.The complete list can be found here at knx.org
The KNX Association has partnership agreements with more than 30,000 installer companies in 100 countries and more than 60 technical universities as well as over 150 training centres.
The access to the KNX specification used to be restricted, however as from January 2016 the access is free assuming you have a free account on the knx association website.