FreeSwitch is a free, open-source application server for real-time communication. It is used to build PBX (private branch exchange) systems, video conferencing and IVR (interactive voice response) services. The server is supported cross-platform, and is used with MacOS, Windows, Linux, Solaris and multiple BSD (Berkeley Software Distribution) descended operating systems of which FreeBSD is the most popular.
FreeSwitch is licensed under a free software license, giving a recipient the ability to adapt and redistribute the software. There are still restrictions, as FreeSwitch is not in the public domain.จ้าง FreeSwitch Developers
Voip billing switch open source latest version sippy or others minimum 10000+ traffic handling with dialer support & hacking protection