So, let’s start from the beginning and establish a base ground: Open Source software, especially that distributed under the GPL, doesn’t imply that it is FREE for re-distribution in any form. The GPL had indicated specific guidelines about how GPL software can be re-distributed in commercial forms. However, putting aside GPL restrictions and various legal mambo-jumbo, we can summarize the GPL distribution limitations according to the following:

1. If you use a GPL licensed product and change it to your own needs, you are not required to make your changes available to the public.
2. If you use a GPL licensed product and change it, then you want to distribute it, you are confronted with one of the following:
   • Provide your customer with a complete source code of the changes.
   • Provide your changes to general public, via an upstream code contribution of a public patch.
   • Obtain a valid license permit from the original GPL holder.

Again, the above is very much generic and doesn’t cover all grounds, however, gives a very good idea of the various aspects. Some GPL software packages, Asterisk for example, are distributed under a dual-license, enabling a developer/vendor/distributor to go about and provide binary packaged versions of Asterisk – pending a proper license to be obtained from Digium.

Israel is most probably the worst place in the world (following China and Africa, of course) when it comes to software license violations. In Israel, people regard Open Source as “Free – do what you want software”, thus, living in complete ignorance of the various implications of violating GPL coded software projects, especially those backed by commercial companies.

This morning, I’ve received a call from one of the larger telco equipment manufacturers in Israel. Actually, this company is so well know, that their CPE equipment is available all over the world – and is even considered one of the best around. In any case, one of their development managers calls me up saying: “We’d like to integrate the Asterisk SIP stack into an embedded environment and resell it – can we get this technical service from your company”. After listening a little more to the man, I’ve indicated that this kind of work will most probably require some licensing from Digium and that we need to approach Digium for that. After explaining the reason, the immediate question followed: “What may happen if we don’t do it and simply modify and integrate the GPL version?” – my answer was: “Well, it will either make your entire product GPL, so you’ll have to release it. Or your product will violate the Digium intellectual property, exposing your company to a lawsuit”.

The man then asked me: “Well, can you help us with that? can you assist in this matter?” – which I replied: “well, let’s meet, I want to understand deeper – but I’m sure that I can help your company in going through this track successfully”.

People tend to forget that licensing of software is very important, not only because of support, licensing enables software companies to extend the life cycle of a product, ensuring its viability and existance in the market for a long time. There are many companies around the world, violating the Asterisk GPL code and proprietary licensing scheme – by doing so, they are cutting the branch they are sitting on. The more violations happen, the weaker the project becomes, thus, at some point in time will break the entire existance model of the project. If you are looking into embedding Asterisk into a commercial product, talk to a consultant, go to an Asterisk class and learn the various aspects, both technical and legal, of its integration and usage in a commercial product.