How an IP 3CX / VoIP Phone System Works

A VoIP phone system / IP 3CX system from C2 Communications consists of one or more SIP phones / VoIP phones, an IP 3CX server and optionally includes a VoIP Gateway. The IP 3CX server is similar to a proxy server: SIP clients, being either softphones or hardware-based phones, register with the IP 3CX server, and when they wish to make a call, they ask the IP 3CX to establish the connection. The IP 3CX has a directory of all phones / users and their corresponding SIP address and thus is able to connect an internal call or route an external call via either a VoIP gateway or a VoIP service provider to the desired destination.


what is a pbx system


At the center we have the IP 3CX. Starting from the bottom, we see the corporate network. This is the company’s local network. Through that network, Computers running SIP clients such as the 3CX softphones, and IP phones connect directly to the 3CX. On the left, we see the company’s router / firewall connected to the internet. From there it can connect to remote extensions in the form of computers running the softphones, remote IP phones, mobile devices running the 3CX Android and iOS apps, and bridged PBX’s. By using the VoIP network of C2 Communications, we can connect you to the PSTN network. To the right, a VoIP Gateway connects the 3CX directly to the PSTN network.