Failure to Create an Open Specification
While there is no hard and fast rule what constitutes as 'open', it is worth noting that despite the KNX association's marketing claims the KNX specification is not open in the same sense as, for example, a HTTP protocol specification is open:
- The text of the KNX specification must be acquired for a fee.
- KNX association as the copyright owner does not grant a license to redistribute the content of the specification.
- KNX association as the copyright owner does not freely distribute the content of the specification themselves.
The factors above create a barrier to adoption of the KNX specification. It is difficult to discuss, evaluate, provide feedback and innovate around a specification that is not freely available to all interested parties. This is in contrast to most Internet protocol specifications for example, and can be argued limits the wide-spread adoption of KNX.
On counter-balance, the license restrictions and copyright of the KNX specification does not exclude a creation of an Open Source or Open Hardware implementations which can be documented freely. If that initial investment is made, KNX could be considered de facto open.
Proprietary Toolset
A more critical factor than the lack of open specification, is the proprietary nature of the KNX toolset. KNX installations must be commissioned with an ETS tool which is a proprietary, Windows-only software package available only under restrictive license and fees. There does not appear to be an alternative, open toolset for KNX. Whether it is possible to create a replacement of the proprietary ETS tool remains an open question.
Incompleteness and Stagnation
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Over-Reaching
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