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
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
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.