> ## Documentation Index
> Fetch the complete documentation index at: https://docs.contactswing.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Outbound SIP Calls

Learn how to set up and manage outbound SIP calls. This guide shows you how to configure outbound calling effectively.

## What is SIP?

**Session Initiation Protocol (SIP)** is a protocol for making voice and video calls over the internet. SIP lets you use VoIP (Voice over Internet Protocol) for calls, offering a modern alternative to traditional phone lines.

## Why use SIP for outbound calls?

SIP-based outbound calling offers several advantages:

* **Lower costs**: Reduce expenses for phone lines and long-distance calls.
* **Global reach**: Call from anywhere with an internet connection.
* **Scalability**: Expand or reduce call capacity as needed.
* **High call quality**: Enjoy clearer audio with a stable connection.
* **Business integration**: Connect SIP with CRM, call centers, and automation tools.

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## Whitelist required IPs

To receive calls from our system, whitelist the following IP addresses:

See the latest IPs in Twilio's documentation:\
[Twilio SIP Trunking IP Addresses](https://www.twilio.com/docs/sip-trunking/ip-addresses)

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## Outbound call initiation

Once you've whitelisted the required IPs, you can initiate outbound calls directly from the **User Interface (UI)**. 🚀