FusionPBX is an open source project that provides a customizable and flexible web interface to the very powerful and highly scalable multi-platform voice switch called FreeSWITCH. Together FusionPBX and FreeSWITCH have been proven to work with hundreds of extensions up to thousands of simultaneous calls. It supports text to speech, speech recognition, supports audio rates from 8kHz to 48kHz. Features are too numerous to list here. Its features can be easily extended with PHP, Javascript, LUA, Perl, C#, C, C++ and more. It is a voice application developers dream come true. FusionPBX uses a database backend with PHP PDO and can support SQLite, MySQL, and PostgreSQL. It is stable and is being used by homes, small business and large businesses from around the world.
