Open-Source Software
The concept behind open-source software is that not only is the application available to the general public at no cost, but the actual source code that created the application is also available and freely distributable. This allows other users of the application to make changes to the source code and optionally pass these changes on to other users of the software.
Asterisk and the other components of TrixBox, however, are released under the GPL (General Public License) that comes with the caveat that when someone makes changes to the original code and decides to distribute the modified version they have to provide it under the same license. There is no obligation to distribute the source code, but if we choose to we must release it under the GPL.
Note
GPL
The GPL is a license produced by GNU (http://www.gnu.org) and is one of the most common licenses used by open-source software. There are many other open-source licenses recognized by the OSI (Open-Source Initiative) (http...