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

# Call Transfer

> Transfer calls to human agents with cold or warm transfer options

Call transfer allows your AI agent to hand off conversations to human team members when needed. telli supports two transfer methods: cold transfer (immediate) and warm transfer (briefed).

## Cold Transfer

Immediately connects the caller to the destination number without any briefing.

**How it works:**

1. AI informs caller they're being transferred
2. Call connects directly to destination
3. AI disconnects immediately

<Warning>
  If the destination doesn't answer, the caller will hear ringing indefinitely.
  The AI agent cannot return to help.
</Warning>

<Info>
  **Technical detail:** Cold transfers use the SIP REFER method. For every cold
  transfer, telli includes `X-Telli-Call-Id` in the SIP REFER request headers,
  with the telli call id as its value for downstream call correlation.
</Info>

***

## Warm Transfer

Places caller on hold while the AI briefs the human agent before connecting them.

**How it works:**

1. AI places caller on hold with music
2. AI calls destination in a separate session
3. AI summarizes the conversation for the human agent
4. Human agent accepts or declines the transfer
5. If accepted: caller connects to the briefed agent
6. If declined/unavailable: AI returns to caller with explanation

**Key advantages:**

* Human receives conversation summary before speaking to customer
* Automatic detection of voicemail or unavailability
* AI can resume conversation if transfer fails
* Better customer experience with informed handoff

### Timeout Handling

| Scenario               | Detection Time | Result                 |
| ---------------------- | -------------- | ---------------------- |
| No answer              | 5 minutes max  | AI returns to caller   |
| Voicemail detected     | 10-30 seconds  | AI returns immediately |
| Agent says unavailable | Immediate      | AI returns immediately |
| Caller hangs up        | Immediate      | Transfer cancelled     |

***

## Configuration

### 1. Add Transfer Numbers

Navigate to **Agent Settings → Calls → Transfer Configurations**

**Required fields:**

* **Label**: Internal name (e.g., "Sales Team")
* **Phone Number**: E.164 format (e.g., +4917612345678)
* **Description**: When to use this transfer (e.g., "For customers ready to purchase")
* **Transfer Type**: Choose Cold or Warm

<Note>
  You can add multiple transfer destinations. The AI will choose based on
  conversation context.
</Note>