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Outbound calling connects your SIP application to an iMessage line owned by your Spectrum project.
Business profile registration is recommended for production, but it is not required. Outbound calls work without any business profile registration, although they may be flagged.

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Before you start

You need:
  • A Spectrum project.
  • An iMessage line in that project.
  • The project’s ID and secret.
  • A SIP client, PBX, or voice application that supports TCP transport.
WhatsApp numbers cannot be used for Spectrum Voice.

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Set up outbound calling

1

Find your project credentials

Sign in to the Spectrum dashboard, select the project that owns your iMessage line, and open its settings.Copy the project ID and project secret. You will use them as SIP credentials:
  • Project ID → SIP username
  • Project secret → SIP password
Use the project ID, not the project’s display name.
2

Add a SIP account or trunk

In your SIP application, create an account or trunk with these exact values:SIP products name these fields differently. The server field might be called SIP URI, domain, registrar, proxy, or host. In each case, use sip.spectrum.photon.codes.
3

Force TCP transport

Select TCP explicitly. Do not leave transport on an automatic setting if your SIP application might choose UDP or TLS.Spectrum Voice currently supports only SIP over TCP. A sips: URI will not work.
4

Connect and authenticate

Start the SIP application and confirm that it connects successfully.If authentication fails, check that the project ID and project secret are from the same project and do not contain extra spaces or line breaks.
5

Place a test call

Place a call through the configured SIP account. Confirm that the call uses an iMessage line owned by the authenticated project.Test call setup and two-way audio before using the connection in production.

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Example configuration

These environment variable names are examples for your own application. They are not read automatically by spectrum-ts.
Keep the project secret in a secret manager or protected environment variable. Do not commit it to source control or send it to browser code.

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Optional: register your business profile

Outbound calling works without a registered business profile. Registration is still recommended because calls from an unregistered business may be flagged. To register:
1

Open the business profile

In the dashboard, select the project that places the calls and open its business profile.
2

Submit the business information

Complete the requested business details and submit the profile. There is no registration fee.
3

Wait for registration to finish

Registration usually takes 1–2 business days. You can continue developing and making outbound calls while it is being processed.
Registration reduces the risk associated with unidentified outbound traffic, but it should not be treated as a guarantee that a call will never be flagged.

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Before going live

  • The iMessage line belongs to the same project as the SIP credentials.
  • The server is exactly sip.spectrum.photon.codes.
  • The username is the project ID, not the project name.
  • The password is the current project secret.
  • The transport is TCP, not UDP or TLS.
  • A test call connects and has working two-way audio.
  • The business profile has been submitted if you want to reduce flagging risk.

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Troubleshooting

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The SIP application cannot connect

Check the server spelling and force the transport to TCP. Disable automatic UDP or TLS selection. Also confirm that your network allows the SIP application to make an outbound TCP connection.

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Authentication fails

Use the project ID as the username and the project secret as the password. Make sure both came from the same project. If the secret was rotated, replace the old value in the SIP application.

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The line is not available

Confirm that the project owns an iMessage line. WhatsApp and voice-only lines are not currently supported for Spectrum Voice.

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Calls are flagged

Outbound calls can work without a registered business profile, but they may be flagged. Register the business profile in the dashboard and allow 1–2 business days for registration to complete.