Hello, I am creating a call center for my business communication and I wish to share my positive experiences. I have found a useful solution provided by Ozeki VoIP SIP SDK so I can connect my remote call center agents to the call center using VoIP technology. You can find a similar sample on this site: google this: voip-sip-sdk.com/p_441-remote-voip-call-center-agent-voip For secure connection and communication, you can use SRTP or SIP line encryption methods in your application. Regards, Ron