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

# Connect Ringingo to Carriers with SIP Trunks

> SIP Trunks are the carrier connections that carry every outbound call. Configure credentials, registration, and codec preferences per trunk.

SIP Trunks are the carrier-level connections that link Ringingo to the public switched telephone network (PSTN) or a VoIP provider. Every outbound call must travel through an active SIP trunk. Each trunk defines the SIP server domain, registration credentials, and codec preferences.

## Trunk list fields

| Field        | Description                                                     |
| ------------ | --------------------------------------------------------------- |
| Name         | Unique label for the SIP trunk.                                 |
| Domain       | SIP server hostname or IP of the VoIP carrier.                  |
| Registration | Online (registered) or Offline (unregistered) with the carrier. |
| Status       | Toggle to enable or disable. Disabled trunks carry no calls.    |
| Actions      | Edit credentials or delete the trunk.                           |

<Warning>
  A SIP Trunk must be registered (Online) before it carries live calls. If a trunk shows Offline, check SIP credentials, network firewall rules, and carrier-side registration settings before assigning it to any Outgoing Rule.
</Warning>

## Create a SIP trunk

<Steps>
  <Step title="Open the form">
    Click **+ Create SIP Trunk**.
  </Step>

  <Step title="Enter carrier credentials">
    Provide Name, Register toggle, Username, Password, Domain, and any Outbound Proxy.
  </Step>

  <Step title="Enable">
    Set Status to Enable to activate the trunk and begin SIP registration.
  </Step>
</Steps>

### Fields

| Field                | Required    | Description                                                                      |
| -------------------- | ----------- | -------------------------------------------------------------------------------- |
| Name                 | Yes         | Unique label used in Outgoing Rule dropdowns.                                    |
| Register             | No          | Yes for carriers that require SIP registration; No for IP-authentication trunks. |
| Username             | Conditional | Required when Register is Yes.                                                   |
| Password             | Conditional | Required when Register is Yes. Masked in the form.                               |
| Domain               | Yes         | Carrier SIP server hostname or IP (for example, sip.carrier.com).                |
| Outbound Proxy       | No          | Optional secondary SIP proxy address.                                            |
| Status               | Yes         | Enable to activate.                                                              |
| Optional Information | No          | Expand for DTMF mode, codec preference, and session timers.                      |

<Warning>
  The SIP Trunk Password is a carrier credential. Keep it confidential. If a credential is compromised, reset it with your carrier immediately and update the value here to prevent toll fraud.
</Warning>