FusionPBX is an open source project that provides a customizable and flexible web graphical user/administration interface for FreeSWITCH and converts it in to a single/multi tenant gateway or PBX system. FusionPBX provides a GUI for unlimited extensions, voicemail-to-email, music on hold, call parking, and many other features. It provides the functionality your business needs, and brings corporate level phone system features to small, medium and large businesses.