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

# Telnyx SIP

> Configuring Telnyx SIP Trunking with Butter AI

This guide walks you through setting up Telnyx to route calls to Butter AI.

## Prerequisites

* A Telnyx account.
* A phone number in your Telnyx account.
* A Butter AI SIP Inbound Trunk created (see [Import Phone Number](/api-reference/phone-numbers/import)).

## Step 1: Create a SIP Connection

1. Log in to the [Telnyx Portal](https://portal.telnyx.com/).
2. Navigate to **Voice** > **SIP Trunking** > **SIP Connections**.
3. Click **Add SIP Connection**.
4. Name it (e.g., "Butter AI").
5. Select **SIP Trunking**.
6. Click **Create SIP Connection**.

## Step 2: Configure Inbound Routing

This tells Telnyx where to send incoming calls.

1. In your new SIP Connection, find the **Inbound** settings.
2. **SIP Transport Protocol**: Select `TCP` (or `UDP` if preferred, but TCP is recommended for reliability).
3. **DNIS Type**: `E.164`.
4. **Expert Settings**: Ensure codecs include `PCMU` (G.711u) and `PCMA` (G.711a).
5. **SIP URI**:
   * Select **Add New IP/URI**.
   * Type: `SIP URI`.
   * URI: The SIP Server Address provided by Butter AI (e.g., `sip.your-region.livekit.cloud`).
   * Port: `5060`.
6. Click **Save**.

## Step 3: Assign a Number to the Connection

1. Navigate to **Numbers**.
2. Find your phone number.
3. In the **Connection** dropdown, select the "Butter AI" connection you just created.
4. Click **Save**.

## Step 4: Configure Outbound (Optional)

If you plan to make outbound calls *from* Butter AI through Telnyx:

1. In your SIP Connection, go to **Outbound**.
2. **Outbound Profile**: Create a new profile or select an existing one.
3. **Authentication Method**:
   * Select **Credentials**.
   * Create a Username and Password.
   * *You will use these credentials when importing a SIP phone number in Butter AI.*

## Step 5: Verify

Call your Telnyx phone number. The call should route through Telnyx to the Butter AI SIP URI and connect to your agent.