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

# Inbound Calls

> How inbound calls are routed to AI phone agents — call flow, session matching, silence detection, call endings, and recording.

Use **[Create Phone Agent](/phone/create-agent)** first if you haven't set up an agent yet.

<Tip>
  **Inbound Calls** covers what happens when a customer calls your number. For agent settings, see [Agent Configuration](/phone/agent-config). For outbound calls, see [Outbound Calls](/phone/outbound-calls).
</Tip>

## Path Of A Call

```mermaid theme={"dark"}
flowchart LR
  A([Caller]) --> B[Phone number]
  B --> C[Route to agent]
  C --> D[AI answers]
  D --> E[Conversation]
  E --> F([End or transfer])

  style A fill:#1a5c20,color:#fff,stroke:#267a2e
  style F fill:#1a5c20,color:#fff,stroke:#267a2e
```

<Steps>
  <Step title="Customer Calls Your Number">
    The customer dials a phone number assigned to an AI agent.
  </Step>

  <Step title="Routed To The Correct Agent">
    **OpenCX** matches the dialed number to an agent. If the number is assigned directly, that agent answers. If the number is on a SIP trunk, the org's default agent answers.
  </Step>

  <Step title="AI Speaks First Message">
    The agent greets the caller with its configured first message (e.g. "Thanks for calling. How can I help?").
  </Step>

  <Step title="Conversation">
    The AI listens, responds using its instructions and knowledge, and can trigger actions or workflows during the call. The full transcript is recorded in the [inbox](https://platform.open.cx/inbox).
  </Step>

  <Step title="End Or Transfer">
    The call ends when the AI says goodbye, the caller hangs up, or the AI transfers the call to a human agent or external number.
  </Step>
</Steps>

## Call Behavior

Includes <Tooltip tip="The agent detects when the caller stops speaking and prompts them before ending the call.">silence detection</Tooltip>, end-call behavior, and interruption handling.

| Behavior              | Detail                                                                                                                                        |
| --------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- |
| **Silence detection** | If the caller is silent, the agent prompts "Are you still there?" up to **2 times**. After that, it ends the call.                            |
| **End call**          | The AI says goodbye and waits for the speech to finish. If the caller **speaks during the goodbye**, the AI re-engages instead of hanging up. |
| **Interruption**      | Callers can interrupt the AI mid-sentence by default. The AI stops speaking and listens.                                                      |
| **Audio quality**     | The AI only responds to clear speech. Background noise, static, or unintelligible audio is ignored to avoid false triggers.                   |

## Good To Know

<AccordionGroup>
  <Accordion title="Session Matching" icon="link">
    Sessions are matched by the **caller's phone number**. A returning caller within the same session window continues the existing conversation.
  </Accordion>

  <Accordion title="Transcripts And Recording" icon="microphone">
    Every call is transcribed in real time. The full transcript appears in the [inbox](https://platform.open.cx/inbox) as a conversation thread, alongside chat and email.
  </Accordion>

  <Accordion title="DTMF Tones" icon="hashtag">
    The agent can detect keypad tones (<Tooltip tip="Dual-Tone Multi-Frequency — the signal generated when a caller presses a key on their phone keypad.">DTMF</Tooltip>) pressed by the caller during the call.
  </Accordion>

  <Accordion title="Call Transfers" icon="arrow-right-arrow-left">
    When configured, the AI can transfer the call to a phone number, SIP destination, or end the call as a workflow hook. Transfer destinations must be assigned to the agent in **[Channels → Phone → Agents](https://platform.open.cx/channels/phone/agents)**.
  </Accordion>
</AccordionGroup>

***

## Related Documentation

<CardGroup cols={2}>
  <Card title="Agent Configuration" icon="sliders" href="/phone/agent-config">
    Voice, instructions, knowledge, actions, and transfers.
  </Card>

  <Card title="Outbound Calls" icon="phone-arrow-up-right" href="/phone/outbound-calls">
    Make AI-powered outbound calls.
  </Card>

  <Card title="SIP Integration" icon="server" href="/phone/sip-integration">
    Route inbound calls from your own carrier.
  </Card>
</CardGroup>