CallMax - PBX solution, softswitch with static routing optimum for VoIP traffic resellers with an opportunity to give prepay accounts based on own subsystem of codes' generation for advance payments. Its a good solution to provide IP communication to land - line, mobile phone users as well as to hotels, students dormitories and enterprises. CallMax has got all necessary features and friendly interface for you to manage your company providing VoIP services to customers. http://speedflow.com/en/software/callshop/pbs
Shortly:
-static routing;
-supports SIP and H323;
-Linux based software;
-authorization by CLI and IP;
-built-in billing with all financial instruments required for clients billing on prepaid basis;