# Connect your own phone system

Source: https://pozy.ai/help/messaging/sip-trunks

SIP is the common way business phone systems connect over the internet. If you have never heard of it, you probably do not need this page. [Call routing](https://pozy.ai/help/messaging/calls-and-voice-agents) covers most needs.

## Forwarding or a trunk?

| You want | Use |
|---|---|
| Calls to ring your phone system or AI agent | Forwarding: set **Inbound routing** to **SIP** on the number. Simpler |
| Your phone system to also make calls with your Pozy number | A SIP trunk |

## Do it in the dashboard

1. Open **Phone**, then **SIP trunks**, and choose **New SIP trunk**.
2. Give it a **Name**, like "Support voice agent".
3. Type the **SIP host** of your phone system. Use the host name only, without sip: or a port.
4. Keep **Transport** on **TLS (recommended)** unless your system needs TCP or UDP. Set the **Port** if it asks for one.
5. Choose **Create trunk**. Pozy shows a **Termination URI**, a **Username** and a **Password**.
6. **Save the password now.** It is shown only once.
7. Enter those three values in your phone system's settings.
8. On the number, turn off **Phone calls** and WhatsApp calling. A number on a trunk cannot run both.
9. Back on the trunk, choose **Attach number** and pick the number.

From then on, calls to that number go to your system. Choose **Detach** at any time, and the number's own call settings come back.

## Or ask your AI

> Create a SIP trunk called Support voice agent for the host sip.example-voice.com over TLS, and attach my London number. Tell me what to enter in my phone system.

## Good to know

- **While a number is on a trunk,** Pozy's voicemail, business hours, IVR menu, recording and browser calling pause. Calls do not show in Pozy's call history. Your phone system keeps the record.
- SMS and WhatsApp messages on the number keep working. WhatsApp calling does not.
- Your system can only show numbers you own in Pozy as caller ID.
- One trunk can hold many numbers. You can also make one trunk per client to keep them apart.
- Each trunk allows 10 calls at once and has a daily spend limit. Ask [support](https://pozy.ai/help/workspace/support) to raise them.
- Lost the password? Choose **Rotate password**. The old one stops working at once.
- Calls bill per minute at the normal rate, from $0.01 a minute.
- Numbers do not support emergency calls.
- If the page says SIP trunking is not enabled for your workspace, contact [support](https://pozy.ai/help/workspace/support).

**Related:** [Buy a phone number](https://pozy.ai/help/messaging/buy-a-number)