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

# Voice

> Add inbound and outbound voice calls to a Spectrum iMessage line over SIP.

Spectrum Voice lets a SIP application, PBX, or voice agent place and receive
live calls through a Spectrum iMessage line.

<Note>
  This guide is about live calls. To send an audio recording inside a message,
  use the [`voice()` content builder](/docs/spectrum-ts/content/voice).
</Note>

## What is supported

| Capability                      | Status        |
| ------------------------------- | ------------- |
| Outbound calls                  | Supported     |
| Inbound calls                   | Supported     |
| iMessage lines                  | Supported     |
| WhatsApp numbers                | Not supported |
| Voice-only ("pure voice") lines | Coming soon   |
| SIP                             | Supported     |
| Webhooks                        | Coming soon   |
| `spectrum-ts` SDK call control  | Coming soon   |
| TCP transport                   | Supported     |
| UDP or TLS transport            | Not supported |

<Warning>
  Configure your SIP application to use **TCP**. Spectrum Voice does not
  currently accept UDP, TLS, or `sips:` connections.
</Warning>

## Choose a setup path

Inbound and outbound calling are configured separately. Set up one or both,
depending on what your application needs.

<CardGroup cols={2}>
  <Card title="Outbound calls" icon="phone-outgoing" href="/docs/spectrum-ts/providers/voice/outbound-calls">
    Configure SIP credentials and place calls from your iMessage line.
  </Card>

  <Card title="Inbound calls" icon="phone-incoming" href="/docs/spectrum-ts/providers/voice/inbound-calls">
    Register inbound routing in the dashboard and receive calls in your SIP application.
  </Card>
</CardGroup>

## Quick reference

For outbound calls, configure your SIP application with these values:

| Setting           | Value                        |
| ----------------- | ---------------------------- |
| SIP server or URI | `sip.spectrum.photon.codes`  |
| Username          | Your Spectrum project ID     |
| Password          | Your Spectrum project secret |
| Transport         | `TCP`                        |

You can find the project ID and project secret in your project settings in the
[Spectrum dashboard](https://app.photon.codes).

For inbound calls, register the inbound route in the dashboard. The dashboard
connects the iMessage line to your SIP application.

## Business profile registration

A business profile is **not required** to place an outbound call. You can start
building and testing before it is registered.

However, outbound calls from an unregistered business may be flagged. For
production traffic, we recommend registering the business profile in the
dashboard. Registration is free and usually takes **1–2 business days**.

<Note>
  Business profile registration and inbound route registration are different:

  * A **business profile** is optional and relates to outbound calling.
  * An **inbound route** is required if you want to receive calls.
</Note>

## Current integration model

Voice is documented as a provider because it is a communication platform, but
it does not yet use a `voice.config()` SDK provider.

Today, your application connects directly through SIP:

* Use SIP over TCP for inbound and outbound calls.
* Use the dashboard to manage the project, business profile, line, and inbound
  route.
* Do not expect voice calls in `app.messages` or `app.webhook()`.

Webhook delivery, SDK call control, TLS transport, and voice-only lines are on
the roadmap. No release dates are promised yet.