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

# SIP Transfer

> Let your agent transfer a live call to a human phone number.

# SIP Transfer

The SIP Transfer node gives your agent the ability to transfer an active call to a human phone number. The LLM decides when to initiate the transfer based on the conversation context — for example, when an issue is too complex or the user explicitly asks to speak with a person.

## Setup

1. Configure a SIP trunk in your LiveKit project (see [LiveKit SIP docs](https://docs.livekit.io/agents/telephony/sip/))
2. Drag the **SIP Transfer** node from the sidebar (Tools category) onto the canvas
3. Connect its output handle to the Agent node's `tools_in` handle
4. Add the phone numbers the agent can transfer to

## Parameters

| Parameter      | Type        | Required | Description                                                                                 |
| -------------- | ----------- | -------- | ------------------------------------------------------------------------------------------- |
| `phoneNumbers` | phone\_list | ✅        | List of phone numbers the agent can transfer to (international format, e.g. `+14155551234`) |
| `playDialtone` | boolean     | —        | Whether to play a dialtone sound during the transfer. Default: `true`                       |

## How it works

When the LLM determines a transfer is needed, it calls the `transfer_to_human` tool. The agent then initiates a SIP call to the selected phone number and bridges the active session.

The agent has access to all phone numbers you configure — the LLM chooses the most appropriate one based on context (or you can configure a single number for a dedicated transfer target).

## Typical pattern

```
[Agent] ◀──tools── [SIP Transfer]
    │
[Start] ──▶ [Categorize] ──▶ [human branch] ──▶ [End]
```

<Note>
  SIP Transfer requires a configured SIP trunk in LiveKit Cloud. See [LiveKit SIP setup](https://docs.livekit.io/agents/telephony/sip/) for instructions.
</Note>

## Use cases

* Escalate to a live agent when the issue is too complex
* Route to a specialist (billing, technical, sales) based on conversation outcome
* Let users opt out of the bot and speak to a human at any time