A scaleable PBX (Private Branch exchange) is provided for use in a powerful, facilities-based, broadband communications system that guarantees voice, data and video communication reliability and security to users for an multimedia system including integrated telephone, television and data network. The...http://www.google.fr/patents/US6728239?utm_source=gb-gplus-shareBrevet US6728239 - Scaleable network server for low cost PBX
