IP-PBX

At its core, an IP PBX phone system eliminates the need for a physical connection to the Public Switched Telephone Network (PSTN). Instead, it relies on Voice over Internet Protocol (VoIP) and Session Initiation Protocol (SIP).

Here is exactly how the call routing works behind the scenes:

Digital Conversion: When you speak, the IP PBX converts your analog voice signal into digital data packets.

SIP Addressing: Every user (or extension) on the network is assigned a unique SIP address.

Internal Routing: If you dial a coworker’s extension, the IP PBX maps the call directly to their SIP address over your local network (LAN). Because it never touches an outside phone line, internal calls are completely free.

External Routing: If you dial an outside number, the IP PBX routes the digital packets through a SIP Trunk directly to your VoIP provider, connecting you to the outside world seamlessly.