FreePBX

FreePBX is a web-based open-source graphical user interface (GUI) that manages Asterisk, a voice over IP (VoIP) and telephony server.

FreePBX is licensed under the GNU General Public License version 3, with commercial modules available under their own licenses. It is a component of the FreePBX Distro, released by the FreePBX project, which is a maintained Linux system derived from the source code of the CentOS distribution with all components needed, including Asterisk, pre-installed and released as a turnkey distribution. FreePBX is also included in other open source distributions such as AsteriskNOW, Elastix and RasPBX.

FreePBX is maintained by a community of developers and contributors using the GitHub platform. The slogan for FreePBX is "Let Freedom Ring".

History
FreePBX was initially released as the Asterisk Management Portal (AMP), version 0.2. The project was renamed to FreePBX for trademark reasons, as Asterisk was a registered trademark of the Digium corporation (which is now also a subsidiary of Sangoma Technologies Corporation). The first release under the FreePBX name was version 2.0.

FreePBX was acquired by Schmooze Com Inc on February 22, 2013.

Schmooze Com Inc was acquired by Sangoma Technologies Corporation on Jan 2, 2015.

Installation
FreePBX up to version 16 can be installed as standalone software, or as part of the pre-configured FreePBX Distro that includes the CentOS Linux operating system, the Asterisk PBX, FreePBX, and assorted dependencies.

As a result of CentOS Linux being discontinued in its stable form, FreePBX 17 is moving over to and will be supported on Debian Linux. FreePBX will no longer be providing a pre-configured FreePBX Distro, but will provide a script to install FreePBX on a fresh install of Debian Linux. In-place migration will not be possible, but will be possible by restoring a backup on the new version from the previous version. It will still be obtainable as standalone software.

Development
FreePBX is written in PHP, JavaScript and shell script and uses the LAMP stack. New releases of Asterisk have been accommodated by various updates to FreePBX. Updates have included new menus and support for additional capabilities such as voicemail, calling queues, fax, multiple languages, DAHDI and a local user directory.

FreePBX maintain the currently released version and the previous release behind this. When a new version is released, the oldest supported version becomes end of life at the same time.

Hardware support
FreePBX supports numerous hardware manufacturers, including Aastra Technologies, Algo, AND, AudioCodes, Cisco Systems, Cyberdata, Grandstream, Mitel, Nortel/Avaya, Panasonic, Polycom, Snom, Xorcom, and Yealink. FreePBX developers estimate the distro has been deployed in millions of active PBX systems in over 220 countries and territories.

When Digium took over the Asterisk project, they released a series of SIP phones that tightly integrate with FreePBX, including provisioning support and apps. Since both FreePBX and Digium were acquired by Sangoma, Sangoma have released a number of SIP phones that tightly integrate with FreePBX.

Sangoma have also released certified appliances to run FreePBX These are custom computer servers already configured with FreePBX. They are rated by the concurrent amount of calls the appliance can handle at once.