Is the following situation with FreePBX standard for VoIP?Why Not Use FreePBX 13? Glad you asked. Despite the freepbx.org  facelift1 and the eternal message that The Free Stands for  Freedom, it turns out the business practices havent changed much  since the Sangoma takeover. If your idea of freedom is a closed  source VoIP platform with no way to emulate the repository used to  manage and upgrade the GPL components in FreePBX 13 and no way to  install the FreePBX 13 GUI or its GPL components other than  switching to the proprietary FreePBX Distro, then FreePBX 13 may be  just the ticket. If youd prefer a RealGPL platform that lets you  choose which components youd like on your server, then keep reading.  And drop the Sangoma and Digium honchos a note and let them know how  you feel about FREEDOM.In relation to a question about Elastix VoIP.  Because Asterisk is under the GPL was inferring that the various systems built on top were also open source -- apparently not.Randomly, after David posted his answer, I'll add that PIAF (PBX In A Flash) has this friendly message:root@arrakis:~ $ root@arrakis:~ $ passwd-master passwd-master - 2.0.5 released on 052613CentOS release 6.4 (Final) - 32 Bit*********************************************************************** In order to run this free and compiled program you must agree to   ** the following:                                                     **                                                                    ** 1. I agree to honor the terms of use set out below                 ** 2. I agree not to reverse engineer any of the binaries             ** 3. I agree not to request the source code for this program         ** 4. I agree to only run this program on a PBX in a Flash system,    ** 5. I agree that this program is an 'independent and separate work' ** 6. By typing Y, I agree that this act constitutes my legal         **    signature and agreement to all of these terms and conditions    **    of use.                                                         ** 7. I agree that no warranty is expressed or implied for this       **    program including any warranty of fitness for any purpose.      **                                                                    ** IF YOU DO NOT AGREE WITH THESE TERMS OF USE DO NOT USE THIS PROGRAM**                                                                    ** Tap the Y key to agree to these terms or ENTER to exit             ***********************************************************************
How open or proprietary are the various PBX systems?
licensing;gpl;gpl 2;proprietary code;linux distribution
Taking some examples from GPLv3 (which clarified something that were considered ambiguous in previous versions):A compilation of a covered word with other separate and independent  works, which are not by their nature extensions of the covered work,  and which are not combined with it such as to form a larger program,  in or on a volume of a storage or distribution medium, is called an  aggregate if the compilation and its resulting copyright are not  used to limit the access or legal rights of the compilation's users  beyond what the individual works permit. Inclusion of a covered work  in an aggregate does not cause this License to apply to the other  parts of the aggregate.The mere act of communicating with other programs does not, by itself, require all software to be GPL; nor does distributing GPL software with non-GPL software.The GPLv2 FAQ clarifies when an aggregation should be released under GPL or not:Mere aggregation of two programs means putting them side by side on  the same CD-ROM or hard disk. We use this term in the case where they  are separate programs, not parts of a single program. In this case, if  one of the programs is covered by the GPL, it has no effect on the  other program. Combining two modules means connecting them together so  that they form a single larger program. If either part is covered by  the GPL, the whole combination must also be released under the GPLif  you can't, or won't, do that, you may not combine them.What constitutes combining two parts into one program? This is a legal  question, which ultimately judges will decide. We believe that a  proper criterion depends both on the mechanism of communication (exec,  pipes, rpc, function calls within a shared address space, etc.) and  the semantics of the communication (what kinds of information are  interchanged).If the modules are included in the same executable file, they are  definitely combined in one program. If modules are designed to run  linked together in a shared address space, that almost surely means  combining them into one program.By contrast, pipes, sockets and command-line arguments are  communication mechanisms normally used between two separate programs.  So when they are used for communication, the modules normally are  separate programs. But if the semantics of the communication are  intimate enough, exchanging complex internal data structures, that too  could be a basis to consider the two parts as combined into a larger  program.and from Wikipedia:if a program consists only of own original custom software, or is  combined with source code from other software components, then the own  custom software components need not be licensed under GPL and need not  make their code available; even if the underlying operating system  used is licensed under the GPL, applications running on it are not  considered derivative works. Only if GPLed parts are used in a program  (and the program is distributed), then all other source code of the  program needs to be made available under the same license terms.So if they included GPL parts in their application, they should release those changes, if they're communicating with those applications they are not forced to.