Best Top 10 FREE PBX Software Open Source Phone Systems

Best FREE PBX Software Open Source Phone Systems.  Hosted PBX services are extremely popular these days. They meet the needs of various businesses, from home-based startups to large enterprises with operations in different locations.

PBX or Private Branch Exchange is a tiny switch that tends to connect telephone between private organizations. There is some PBX provider that offers packages that offer for most of the business, however, is not suitable for everyone. A few of them look for specific features or security better than cloud-hosted PBX products offers.

Moreover, there is plenty of open-source PBX software solution available for the business who require more customized solutions. These softwares are entirely free and can be used according to the needs of the enterprises. They also turn themselves into a fully allied communications suite, if required.

Therefore, in this blog, we provide you with the list of the top ten free PBX software open-source phone systems. But, first, let us give you a detailed overview of what is it and how it works.

What Is PBX Software?

what is pbx

With the creation of the Internet, there come several distinct ways of communication. First, email, then messaging. However, the traditional phone systems proved to be relatively expensive for businesses that communicate globally. So, organizations found PBX as the most prominent way of communication.

PBX stands for ce over Internet Protocol. A type of hardware and software used for connecting people through telephone-like calls over the Internet. It allows you to turn the computer into a communication platform.

Through PBX, businesses can create a real-time communication channel. Then, with the help of the Internet Connection, they tend to develop ce or video calls internationally. Businesses use this highly efficient software frequently to make international calls or fax documents.

How Does A PBX Software Work?

PBX is considered an insurgent technology that works in transforming the ce into a digital signal. It then transfers the ce on the Internet using Ethernet (TCP/IP) Protocol.

Through PBX, organizations tend to receive or make calls anywhere across the world with the help of a computer, phone, mobile phones, data-driven devices, or even a traditional telephone that is connected to the PBX adapter called Analog Telephone Adapter.

Top 10 FREE PBX Software Open Source Phone Systems

Based on the popularity, updates, latest development, maturity, and application relevance, the top free PBX Software are as follows.

1. Asterisk

asterisk pbx

Asterisk Sponsored By Digium, Asterisk is one of the best and the idle open-source software that provides both PBX functionality and advanced features of P. Along with a PC running Windows, this software replaces existing switches, expands a PBX, adds ceOverIP, conferencing, cemail, and numerous other capabilities.

Moreover, several cloud-based PBX solution providers use Asterisk to power their sources. The software comprises multiple features that continuously grow year after year. It has the capability of turning any PC into a communication server. It is not only used by large enterprises but also several other small enterprises, call centers, and Governments to power their IP PBX system, P gateways, and Conference servers.


  • It consists of an automated attendant.
  • It delivers detailed call records.
  • It enables the business to forward and block calls.
  • It allows answering calls remotely.
  • It stipulates visual message or ce call waiting.
  • It offers an ADSI on-screen menu system.
  • It provides an enabled Caller ID.

2. FreePBX


Do you want to take the advantage of the functionality, power, and flexibility of the Asterisk? FreePBX is the best Open-Source platform available. It is a web-based, Graphical User Interface (GUI) that assists the users in managing and configuring their Asterisk-based system efficiently.

With the help of this open-source software, users can build a scalable business phone system for any budget. However, those who want to set up an entire PBX server can obtain a comprehensive package consisting of a pre-configured Linux Operating System, the Asterisk System, the GUI, and the dependencies necessary to make everything work altogether.  Check our guide on FreePBX Hosting in the Cloud on Azure, AWS or GCP.


  • It enhances the system with a long list of commercial modules and add-ons.
  • It comprises a reseller program to ensure proper training, quality, and stability, to resellers and end-users.
  • Provides training and education to sales and support teams who are trying to repackage or sell their products. 
  • It also allows the user to establish unlimited SIP trunks with the help of SIPSTation integration.

Setup FreePBX on Azure

Setup FreePBX on AWS

Setup FreePBX on Google

3. SipX

sipx PBX

SipX is an open-source PBX software application that executes the Session Initiation Protocol (SIP) to establish an IP-based communication system. This standard-based SIP open architecture makes the software relatively popular to both middle or large enterprises. The writing in it is done using C++ and Java and implementing RESTful APIs. It can be customized effortlessly according to the business requirements since it contains an open design for straightforward automation.


  • It tends to generate directory information automatically.
  • It enables you to block outbound calls.
  • It allows multiple calls in a single phone line.
  • It authorizes you to set up DnD (Do not Disturb).
  • It assists you to determine the name and location of the callers.
  • With the help of this software, video and ce conferences are made possible.
  • It enables you to transfer, hold, and retrieve calls.

4. Elastix

elastix pbx

Originally based on Asterisk, Elastix is a complete unified communications solution, including IP PBX, email, integrated with fax, IM, and collaboration functions. Though highly focused on the entrepreneurial market, the software is solely free for both commercial and personal use.

The objective of Elastix is to bring the greatest features of Asterisk and other projects under an easy-to-use interface. It enjoys the support of a wide range of hardware like Digium, Dinstar, Yeastar, Snom, and Yealink. It is an online phone provisioning tool that supports IP phones and configures them immediately using this program. Therefore, it is one of the best free open-source PBX software.


  • It offers a call center module with predictive dialing through Web Interface.
  • It provides numerous software packages with unique functionality.
  • It contains improved reporting and control.
  • It offers a sturdy solution under the General Public License (GNU) for free.

5. SIPfoundry


Established in 2004, SIPfoundry gives tough competition to Asterisk. It offers similar functionality to that of the Asterisk engine. The user working in SIPfoundry can customize their communication system according to the needs of the business. The SIPfoundry allows you to create ce and video communications, conferencing, unified messaging, IM and chat with presence indications, and even a mobile client.


  • It offers a customizable Unified Communication solution.
  • It provides free services for downloading it, setting it up, and modifying its code according to the user’s preference.

6. OpenSIPs


Focused more on the open-source SIP server implementation, it allows you to create a unified communication system and a telephone system. It offers effortless customization because of its scalable and modular design. Moreover, it not only supports the ce but also supports IM, services, video, and presence.

OpenSIPs is one of the fastest open-source SIP servers and offers a sturdy solution at an enterprise or carrier-grade class.


  • It provides Benchmark and performance testing to empower the claims.
  • It offers webinar recordings, an in-depth setup that can be effortlessly downloadable.
  • It utilizes both manual ans webinar archives to download these recordings.
  • The Set-up portals on the web make the gathering statistics and information of the user’s service effortless.
  • It also uses fly configurations.

7. Kamailio

kamailio PBX

With over 15 years of solid industry experience, the Kamailio is developed by an experienced team of developers. Since its development, the team has never stopped adding new features and functions to it. The software is considered the most secured platform with multiple authentication and authorization methods.

Thus, this makes the software an appropriate choice for businesses dealing with private information regularly. Moreover, it provides highly advanced functions like automatic load balancing, least-cost routing, and routine fail-over.


  • It ensures secure communication for your PBX data with TCP, UDP, SCTP, and TLS.
  • It requires robust knowledge of the SIP protocol to control the platform effectively.

8. FreeSwitch


FreeSwitch is an open-source cross-telephony platform that is developed to simplify routing and interconnection of audio, video, text, and other communication application.

It was designed by the three original developers of Asterisk. They believed in leveraging the advanced technology so that it can support all three communication technologies, namely, SIP, H.323, and WebRTC. It mostly focuses on modulatory, scalability, cross-platform support, and stability with makes it the most flexible platform. With the help of these features, it allows you to build your own UC suite.


  • It uses free software libraries to perform the necessary functions for the system to work.
  • Along with the usual calling features, it has extra speech recognition, synthesis, and PSTN interfaces for analog and digital circuits.
  • It effortlessly automates and interfaces with other popular open-source PBX platforms available.
  • It offers SIP features that include presence/BLF/SLA, with TCP/TLS/ and SRTP.
  • Apart from working as an SBC (Session Border Controller) and proxying t.38 and other protocols, the user can also use it as a transparent proxy.

9. OpenPBX by Cetronix


OpenPBX is a service of cetronix, a telephony solution and equipment provider offering a wide variety of hardware. It is a web-based PBX application that uses a web-enabled management portal and management GUI for immediate and straightforward configuration.


  • Auto-attendant, automatic call distribution, unlimited cemail, and least call routing hunt groups.
  • It is a robust solution for businesses that need staple call or contact center software.
  • It has basic CRM enabled in it that saves the users time and money.
  • It even allows cemail to email, click to dial, and call transfers.

10. 3CX

3cx pbx

3CX is a business phone system that is easy to operate and runs on a Windows server. It is convenient since it enables you to use any SIP- compatible softphone with your system. It provides multiple functions that make it effortless for the users in connecting with their leads and customers. It is why it comes under the best free PBX open-source phone systems.


  • Since it sets up effortlessly and can run on a Windows server, it is compatible with those who ad Linux box configuration to deploy their PBX.
  • It uses the power of WebRTC and delivers a video conferencing function.
  • It allows its users to use the “Click To Call” function in their web pages or mobile apps to support integration with many primary CRM systems.
  • It provides multiple online references and training materials to provide its user with an overview of the software.

Best Top 10 FREE PBX Software Open Source Phone Systems Final Thoughts

Effective communication is crucial for every organization to move further in their business. Thus, it is essential to establish a low-cost and highly effective communication software that not only builds a relationship with your clients but also provides help to your employees and associates. The enterprises can achieve the desired level of communication with the help of these free and open-source PBX software.

Avatar for Hitesh Jethva
Hitesh Jethva

I am a fan of open source technology and have more than 10 years of experience working with Linux and Open Source technologies. I am one of the Linux technical writers for Cloud Infrastructure Services.

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