Centritech specializes in deploying Asterisk-based VoIP IP-PBX telephone systems in call centers and for multi-location offices over a wide area. We deploy Asterisk and other open source software technologies and tailor every system to the precise requirements of each client. Our systems have more features than even Cicso CallManager and are substantially less expensive. NEW: Centritech also offers Six Sigma analysis of call center effectiveness and customer service.