Open Source IP PBX Options

If you are like the many people of the world who contemplate building an in-house phone system with an open source IP PBX, the decision of what to use is daunting.

Fortunately, the software PBX menu is filled with several good choices, though some are more filling than others. Each system software we will cover is like an entrée but not all come with salad and a potato without a special request.

The Big Picture

We covered the main differences of core capabilities for FreeSWITCH and Asterisk not long before completing this blog. Each underlying system boasts its own benefits and weaknesses. When it comes to the feature set for each system, minor differences are prevalent between the platforms, namely in terms of operability, which makes it a little bit of a difference for the user.

Perhaps one of the best parts regardless of system choice (especially for a new user) is the fact that skills transpose nicely between the systems. Thoroughly learning how to set up any of the IP PBX systems in the market provides a “cross-training” experience where some of the skills gained will apply to other platforms.

Overview of the Most Popular Systems

Each system is slightly different in terms of layout and features. Generally speaking, most of the systems we cover offer all the modern features of a great communication solution however, all require some work to implement certain features and usually some finagling to get everything working properly.

Below is a small table providing a high-level analysis of each system. Yes, there are other systems on the market but from a firsthand experience, the five we cover in this blog boast the fewest issues while yielding enough documentation to guide through some of the more troubling processes of configuration. The size column represents an approximate online community size.


Full Distro Platform Cost Size
3CX Logo edit Windows Proprietary Free2 47000+
elastix-100x75 Yes Asterisk Free3 14100+
FreePBX Logo edit Yes Asterisk Free3 32100+
sipXcom Logo edit No1 FreeSWITCH Free Unclear
fusionpbx-100x75 No FreeSWITCH Free Small & dispersed

Table 1: Overview of Popular IP PBX Systems

*1 – At one point full distributions were available, meaning more may become available down the road.

*2 – A limited basic version is available. The Standard edition starts at $392 and the Pro edition pricing begins at $505 (based on the current Euro/USD exchange rate.) Not open source, but since it has a free version we decided to include it.

*3 – Most features are available free of cost however, some modules for features such as faxing, endpoint management, VPN access, et al, come with a price.


This software is very distinguishable among all the systems as it runs directly on top of Windows whereas all other systems sit on top of a Linux installation. Despite being a proprietary system rather than open source, the basic system is free to use hence the reason we included it here. More powerful versions can be purchased for a price.

This is perhaps one of the easiest systems to learn as documentation is plentiful and the installation is a breeze. Its best feature is also one of the worst features – the system runs on Windows. I would recommend treating it like any other kind of server application and use a stripped down Windows system for stability purposes.

Starting with the Basic edition, several testing mechanisms and user-friendly logs are available to help with the configuration process. One of my favorite features of the system is the auto-provisioning feature that works with just about every popular phone on the market.


This is one of several systems utilizing FreePBX to interact with Asterisk. The software itself is free but the company also boasts an impressive set of both paid items and free services for this full-fledged PBX system as well as an impressive training curriculum.

Like some of the other FreePBX-rooted Asterisk systems, distributions are available so it is very easy to install the system. The support community is not quite as large as other systems however, paid support is an option for those serious about using (or developing) for Elastix, not to mention, a credentialed training program is available.

The two greatest values for this free system lie in the ease of installation and the free modules. The promoted modules, available to browse and install directly from the UI, are generally very well supported.  Admins can even install the Call Center module and the WebRTC Agent Module for a purely, web-based calling solution and both are free!


The core system from FreePBX sets the bar for most Asterisk-based systems. Other systems such as Elastix, PBX in a Flash and the late Trixbox, use FreePBX as the foundation for interfacing with Asterisk.

The software is licensed under the GNU General Public License thanks to the company Schmooze which was recently acquired earlier this year by the North American company Sangoma Technologies. Ownership may have changed but historically (and as of this time of writing) the software is incredibly easy to install and plenty of online documentation is available to help you along the way.

In itself, FreePBX can accomplish just about everything desired in an IP PBX. Creating a simple setup for making and receiving calls takes very little effort, at least after some time is vested in learning how to maneuver the system. Some additional modules to help accomplish various tasks are available for free but others (e.g. the commercial End Point Manager) require payment.


This FreeSWITCH based system was originally developed under the label sipXecs until leadership shifted and part of the development team moved to the sipXcom project. Though the underlying platform is much younger than Asterisk, it is a very impressive system.

Installing this system could be a little problematic if you do not mesh well with a command line. Fortunately, the installation is a very short process compared to some systems if reading an appropriate guide. Configuration of the system is a little different than more established Asterisk systems yet it works very well once the appropriate tweaks are applied. Since the system is in a bit of a rebirth period, finding documentation is a little difficult however, the Wiki page is coming along nicely plus, a growing group of people in the official Google Group are available for help troubleshooting.

Perhaps one of the most standout features for sipXcom is the inherent ability to provide multi-tenant support. If developing a larger system for catering to the needs of multiple companies or dispersed offices, this is the ticket. The systems also cluster at a platform level which allows the admin to distribute tasks among different systems.


This is another example of a great system that boasts multi-tenant capabilities like sipXcom. FusionPBX is one of the oldest existing systems using FreeSWITCH on the market and it shows in terms of power and features.

Installing the system can be a little frustrating because of the lack of documentation. Fortunately, we produced a guide for this system like the other systems mentioned in this blog. Once it is running, the system can be configured for calling with minimal effort and the GUI is very intuitive.

The features parallel that of most other systems on the market and the FusionPBX teams holds a training class every few months around the U.S to help you get up to speed faster. It also has advanced classes and even a development class for those that want to design new features and help the FusionPBX community.

In Conclusion

The most common question when discussing the IP PBX market is, “which is best?” However, this is not an easy question to answer, as the topic is so multifaceted. Everyone has different needs. Not to mention, some factors include ability (and patience) to create a great system.

If you are just now sitting down at the table and deciding which PBX to try, I would recommend starting with either FreePBX or 3CX. These systems are well documented and quickly produce results with a little dedication. The FreeSWITCH based PBXs are better for those needing a more powerful phone system in terms of concurrent call requirements.

Of course, other systems on the market like AsteriskNOW and PBX in a Flash accomplish many of the same feats as the above named systems. Check out our guides and look at the company websites responsible for each respective PBX. Perhaps you have already experimented yourself – what is your favorite IP PBX?

About the author  ⁄ Tony

Tony is one of our senior contributors at He has a vast knowledge of VoIP and produces thought provoking content that our readers enjoy.

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