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Twilio is a web-service API that lets you use your existing web languages and skills to build voice and SMS applications. We focus on building a simple, powerful, pay-as-you-go communications platform so that you can focus on what you do best.

3CXPhone is a free VoIP phone available for Windows, iPhone or any Android based smart phone such as Google Nexus, Sony Xperia, Motorola Droid or Samsung Galaxy. Connect 3CXPhone to a VoIP provider or to a VoIP PBX (for example 3CX Phone System) to make calls to any VoIP, mobile or landline number.

FreeSWITCH is a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media. It was created in 2006 to fill the void left by proprietary commercial solutions. FreeSWITCH also provides a stable telephony platform on which many telephony applications can be developed using a wide range of free tools.

XiVO is a scalable platform based on Asterisk that offers a free and complete PBX solution. It is licensed under the GPLv3.

Your Open Source Solution For Unified Comunnications And More…

Incredible PBX is a secure and feature-rich implementation of the Asterisk® PBX. By rethinking the PBX security model from the ground up.

Yate is a softswitch (concept of separating the network hardware from network software).

Starfish PBX aims to be an open source alternative to Digium’s Switchvox. The goal is to have a software equivalent to which we can add additional functionality like:

Elastix is an open source Unified Communications Server software that brings together IP PBX, email, IM, faxing and collaboration functionality. It has a web interface and includes capabilities such as a Call Center software with predictive dialing.

VoipSwitch is a SoftSwitch System with routing and billing, with SIP protocol support (in older versions also H323).

PBX in a Flash is a PBX system based on Asterisk, FreePBX and CentOS, coming as an ISO download. A two stage installation process allows for more flexibility for the installation of the PBX specific components. The Asterisk components are compiled from source during the install process which allows for easier adaptions later on. The system is update-able without re-install. A script collection on pbxinaflash.org allows for easy extension of the base system.

A SIP based implementation of a PBX / unified communications system.

FreeSentral is a full IP PBX consisting of a Linux Distribution, an IP PBX and a Web Graphical User Interface for easy configuration