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

# Telephony overview

> How AssistPulse handles phone calls using Telnyx.

## How telephony works

AssistPulse uses **Telnyx** as its telephony provider to handle inbound phone calls. When someone calls your agent's number:

1. Telnyx receives the call and routes it to AssistPulse.
2. A real-time session is created with OpenAI's Realtime API.
3. Your agent answers with its configured greeting.
4. Audio streams bidirectionally between the caller and the AI model.
5. When the call ends, a transcript and summary are generated.

```mermaid theme={null}
sequenceDiagram
    Caller->>Telnyx: Dials phone number
    Telnyx->>AssistPulse: Routes inbound call (SIP)
    AssistPulse->>OpenAI: Creates realtime session
    OpenAI-->>AssistPulse: AI responses (audio)
    AssistPulse-->>Telnyx: Agent audio
    Telnyx-->>Caller: Agent voice
```

## Getting started with telephony

> [card] [Buy a number](https://docs.assist.fm/telephony/buy-number)
>
> Search for and purchase a local phone number for your agent.

> [card] [Regulatory documents](https://docs.assist.fm/telephony/regulatory-docs)
>
> Upload required identity documents for certain countries or number types.

> [card] [Inbound calls](https://docs.assist.fm/telephony/inbound-calls)
>
> Understand how inbound calls are routed and processed.

## Supported countries

Phone numbers are available in many countries. The most common:

| Country | Number types |
| - | - |
| 🇳🇱 Netherlands | Local, national (085) |
| 🇧🇪 Belgium | Local, national |
| 🇩🇪 Germany | Local |
| 🇬🇧 United Kingdom | Local, national |
| 🇺🇸 United States | Local, toll-free |

> [!NOTE]
>
> Availability varies by region and number type. Some countries require regulatory documents before a number can be activated.


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