For a while now I have been mulling over the exact license that the packet logger utilities and the reverse-engineered PGN information that I created should be available as. I have now decided to release the software and data descriptions under a Creative Commons Attribution NonCommercial-ShareAlike 3.0 Unported License.
What this means is that you can use my data or programs as long as you make it clear where you got the information and programs from, and that you must license your work under such a license as well. All commercial use is prohibited.
The main reason for doing this is to make it very clear that my intention with releasing the list of PGN data fields is not to undermine the NMEA nor their licensing policy [which claims full copyright over the NMEA 2000 standard], but to make the development of 'open' software possible.
Developers that want to develop a commercial product based on NMEA, in my opinion, should become a member of the NMEA and buy the necessary documentation from them. The only thing holding back commercial developers is cost -- there is a fee associated with becoming a NMEA member, and for the documentation as well. One could argue that the fee structure is wrong (as it favors big companies over small companies) but I think that is something for commercial developers to discuss with the NMEA.
However, someone who wants to develop an open source program or utility cannot become a member and obtain the documentation, as members of the NMEA are not allowed to divulge the exact content of the PGNs to non members. Thus for the open source community there is no alternative but to reverse engineer the data structures from scratch.
This now is what I have done -- just by looking at the public documentation that the NMEA has provided and then trying to make sense of the bits you find on an actual live NMEA 2000 bus. Such reverse engineering is perfectly legal, and in my opinion moral as well as long as I do not claim that it is 'official' NMEA information.
Is the NMEA right?
Obviously the NMEA does what it feels is best for their organization, and they have the right to exercise their copyrights.
However, I do think it is a mistake not to have a process or program in place that allows any open source development on top of the NMEA 2000 protocol.
It also frustrates advanced users that want to see how the very expensive stuff that they have bought interacts with each other, and why certain things are maybe not working the way they should.
For now the source code for the programs is not released yet. I will probably do so at some point, with the exception of the Actisense NGT-1 interfacing programs. The NGT-1 interfacing programs use material that is copyrighted by Actisense, and I have signed a NDA with them -- and thus I cannot reveal how the NGT-1 works.