Frequently Asked Questions about the CERN Open Hardware Licence


CERN OHL v1.1

Q: We like to publish one of our HW design to the open source. Therefore we are looking for an “open hardware license” to be used. In this process we found the CERN OHL v1.1 which could be a good choice.
In the “Guide to the CERN OHL v1.1” is pointed out that one should include “Licensed under CERN v1.1” on the silkscreen. To this paragraph I got the following question:
  • Is this a MUST ? (The prints are already produced and for further productions we do not have much empty space on the board)
  • What is the legal consequence if this is missing?
  • Does a licensee necessarily need to add the notice on the silkscreen?

A: The Guide is here to provide guidance and assistance as to how to apply the CERN OHL.
Indeed, space can be an issue. The idea behind this recommendation is to have it known that the hardware one would come across is licensed under CERN OHL. However, under CERN OHL v.1.1, the Documentation must accompany the hardware that is being distributed (article 4.1) and in the Documentation, the licence notice must appear, and must not be removed by licensees (article 3.1).
So to summarise, adding the licence notice is not a requirement, but as licensor, it is one of the best ways to make it known that the hardware is Open (Source) Hardware since it may well get ‘separated’ from the Documentation in its life. The licensee does not have to add the notice on the silkscreen, however if the licensor has put it there, he may not remove it.


CERN OHL v1.2

Q: What are the main differences between v1.2 and v1.1?

A: Version 1.2 is lighter on the users of the licence. Now licensees who modified a design no longer have the obligation to notify the changes to upstream licensors. In addition to that, in order to guarantee that recipients of CERN OHL-licensed hardware get access to the design documents of a specific piece of hardware, version 1.2 includes the notion of Documentation Location. Another difference between the two versions is that Intergovernmental Organizations such as CERN are not singled out regarding their rights anymore. This means that they are as any other licensor or licensee.

Q: What is the motivation for the sentence "However, the Licensor shall not assert his rights under the foregoing proviso unless or until a Product is distributed" in paragraph 3.3?

A: The Licensee receives a right (to modify the Documentation) upon the fulfillment of a condition (to make the Documentation available). Without the sentence above, the obligation for publishing would be enforced as soon as the modification happens, which would make it impossible to fulfill.