KNX Association cvba was founded in May 1999 by members of EIBA, EHSA and BCI, the associations behind the European Installation Bus, the European Home Systems and BatiBUS, and is governed by Belgian law. It owns and maintains the KNX standard, published internationally as ISO/IEC 14543-3 and in Europe as EN 50090, with KNXnet/IP as ISO 22510, and develops ETS, the engineering tool every KNX installation is configured with. Its manufacturer members, more than 500, have more than 8,000 certified devices, and more than 75,000 KNX Partners in over 190 countries are trained installers and integrators. Products are certified after testing at KNX accredited test labs.
OT Fabric is not affiliated with KNX Association. This profile is independent and based on the organization's own published pages, linked next to each fact. KNX is the authority on its terms and fees.
Each question is separate, because "open" and "free" mean different things here. A yes always means open or free to someone who is not a member.
Published examples as listed on the organization's pages on 30 Oct 2026. Where a page does not say whether a fee recurs, we do not guess.
| Tier | Published fee | Who can join | Votes | Working groups | Source |
|---|---|---|---|---|---|
| Shareholder | €2,500 to €12,500 a year | Companies, by number of staff, approved by the KNX Executive Board.Plus one share of about EUR 1,500, or ten shares above 100 staff, refunded on resignation depending on the year's result. Renews yearly. | Unknown | Unknown | support.knx.org |
| Licensee | €1,000 to €2,000 a year | Companies that pay a royalty instead of shares.1 % of KNX sales at the end of the year, with a minimum of EUR 1,000 below 100 staff and EUR 2,000 above; five-year term. | Unknown | Unknown | support.knx.org |
| Interested Party | €1,000 to €2,000 a year | Companies, without shares: EUR 1,000 below 100 staff, EUR 2,000 above. | Unknown | Unknown | support.knx.org |
| Scientific Partner | €500 | Universities, technical institutes and research bodies.A one-off fee. | Unknown | Unknown | support.knx.org |
On the IP side KNX has an unusually strong open field: four mature, independent stacks, Calimero, knxd, xknx and KNXUltimate, carry KNXnet/IP into Home Assistant, openHAB, Node-RED and many gateways, and the public specification is free with a MyKNX account.
Devices are a different story. Certification and a manufacturer code need membership, which sets the open device stacks, thelsing's knx and its OpenKNX fork, apart from certified commercial stacks such as TAPKO's; open libraries mostly reach the bus through certified IP interfaces and routers.
go-knx implements KNXnet/IP and KNX Secure from public sources, has no manufacturer code of its own, is not KNX certified and makes no conformance claim; it uses the word KNX descriptively, as a registered trademark of KNX Association cvba.
Independent open-source work on the same protocols. Listing them here does not mean they are certified by or associated with KNX.
KNX over KNXnet/IP: frames, cEMI and 209 datapoint subtypes, discovery, tunnelling over UDP and TCP, routing, group communication, device management, busmonitor and a KNXnet/IP server with virtual devices, with KNX IP Secure, KNX Data Secure and ETS keyrings. Pure Go, no dependencies, no cgo.
go get github.com/otfabric/go-knxDiscover and diagnose KNXnet/IP interfaces, monitor group telegrams, read and switch group objects, watch routing and busmonitor traffic, read interface properties, use KNX Secure with ETS keyrings, encode and decode datapoint types and frames, and run a simulated KNXnet/IP server. Passive by default.
Four independent KNX implementations in containers behind one contract: Calimero server and tools, knxd, xknx and KNXUltimate, with a raw probe for negative tests, across tunnelling, routing, datapoint types, TCP, device management and KNX Secure.
Verified on 30 Oct 2026; due for a re-check by 28 Apr 2027 (180 days). Found something out of date? Report a correction or edit the data on GitHub.