---
title: "SIP trunk vs a number from CallWhiz AI"
description: "Connect CallWhiz AI to your existing telephony over SIP, or take a number from CallWhiz AI. This guide explains what each option keeps, what it needs, and when to combine them."
url: "https://callwhiz.ai/docs/sip-trunk-vs-number"
updated: "2026-09-21"
---


# SIP trunk vs a number from CallWhiz AI

CallWhiz AI works either way: over SIP into the phone system you already run, or on a number CallWhiz AI provides. Both directions, inbound and outbound, work from the same agent in both cases.

## Definitions

- **SIP trunk:** A connection that carries your phone system's calls over the internet. CallWhiz AI connects to your existing setup through it.
- **Number from CallWhiz AI:** A phone number provided by CallWhiz AI, available in 20+ countries.

## Connecting over SIP

You keep your numbers, your carrier and your rates, and CallWhiz AI connects to your existing cloud or on-premise platform. Nothing about the phone system changes. Bring your own carrier account if you have one.

## Taking a number from CallWhiz AI

Numbers are available in 20+ countries, with call destinations in 180+. This is the faster path when there is no phone system to connect, or when a new line should be separate from the existing ones.

## Combining them

Routing is per number, so one account can run an agent on a SIP-connected line and another on a number from CallWhiz AI at the same time. An agent can be swapped on a number without touching the carrier.

## Related questions

**Does CallWhiz AI work with my existing phone number and phone system?** CallWhiz AI connects over SIP to the telephony you already have, including major cloud and on-premise platforms, so you keep your numbers, your carrier and your rates. You can also take a number from CallWhiz AI: call destinations in 180+ countries, with numbers available in 20+.

**Which countries can CallWhiz AI call?** CallWhiz AI can place calls to destinations in 180+ countries and offers phone numbers in 20+ countries. You can also bring your own carrier account and keep your rates.

## Related

- [Connecting CallWhiz AI to your phone lines over SIP](https://callwhiz.ai/docs/telephony)
- [Running outbound campaigns with CallWhiz AI](https://callwhiz.ai/docs/outbound-campaigns)