FreePBX

FreePBX simplifies the installation and configuration of an Asterisk based open source phone system, on a server or in a virtual environment.

The value it adds is precisely the part Asterisk leaves to you. Asterisk is a framework configured through text files and dialplan scripting, which is powerful and unforgiving, while FreePBX puts a web interface over it so extensions, trunks, queues and routing are configured through a browser. That difference is what makes an open source phone system deployable by an IT generalist rather than a telephony specialist.

The current release, FreePBX 17, is documented as a genuinely short sequence: install Debian 12 with at least 2GB of RAM and 20GB of disk, then run the FreePBX installation. Publishing concrete minimum specifications rather than vague recommendations is more useful than it sounds, since undersizing a PBX produces call quality problems that are miserable to diagnose after the fact.

Two routes are offered. On a cloud provider, use their built-in Debian 12 image if available, or follow the step-by-step Debian installation guide manually. On physical hardware the FreePBX Distro ISO skips the operating system step entirely, which the project notes is especially nice on bare metal. FreePBX is free and open source, with commercial modules and support available from Sangoma, who maintain it.