# SIP Trunk

A **SIP trunk** is a way for businesses to make and receive phone calls over the internet instead of using traditional telephone lines.\
SIP stands for **Session Initiation Protocol**, which is the standard technology used to set up and manage voice calls, video calls, and messaging sessions online.

Think of a SIP trunk as the digital replacement for the old telephone trunk lines. Instead of running physical wires for each phone line, a SIP trunk uses your existing internet connection to carry voice traffic.

#### Why Businesses Use SIP Trunks

* **Cost Savings** – Calls, especially international ones, are typically much cheaper than with traditional phone lines.
* **Scalability** – You can easily add or remove call capacity without installing new hardware.
* **Flexibility** – Calls can be routed to office phones, mobile devices, or softphones (apps on your computer or smartphone).
* **Unified Communications** – SIP trunks don’t just support voice calls; they can also carry video and messaging.

#### How It Works

1. Your business phone system (PBX, cloud phone, or VoIP platform) connects to a SIP trunk.
2. When a user makes a call, the SIP trunk sends the call over the internet instead of a traditional phone line.
3. The SIP provider then routes the call to the destination number (landline, mobile, or another VoIP system).
