The Mixpbx is a complete, fully featured PBX for small and medium enterprises. It combines the advantages of a hosted PBX (IP Centrex) and a standard in-house PBX. The configuration is managed and stored centrally but the MIXpbx offers the redundancy and fallback possibilities of an on-premise installed system. The Mixpbx works even if your Internet connection is down. A list of supported hardware is available here.