SignalWire (bring your own number)
The SignalWire connection lets a ThunderPhone agent handle calls on a production number routed through your SignalWire SIP trunk. SignalWire continues to supply the number and telephony connection. ThunderPhone supplies the agent configuration, including the prompt, call-direction settings, attached knowledge, and tools.
What the SignalWire connection does on ThunderPhone
SignalWire connects over SIP. In ThunderPhone's VoIP setup, SignalWire has its own tile that opens the manual SIP form with SignalWire-specific steps, and the saved connection is a manual SIP configuration. This establishes call transport between the trunk and ThunderPhone; there is no API-key account connection, and it should not be read as a native data integration with the rest of a SignalWire account.
The form accepts the SIP domain or URI, optional username and password, port, transport, and an optional allowed-source-IP list. The setup-guide generator produces provider-specific instructions for the trunk side. Before saving, Test & Save Connection checks that the SIP domain resolves to a public address and, for TCP or TLS, accepts a connection on the chosen port (UDP gets the DNS check only). It cannot place a call yet, because the connection has no numbers.
Once connected, import the number. Importing verifies it: ThunderPhone places a short test call from the number, through your SignalWire trunk, to a ThunderPhone number. That proves the outbound path, including your credentials, trunk selection and whether the carrier accepts the call; the number becomes active only after it passes. It does not call your number, so it does not test inbound routing. To prove that, call the number from any phone and confirm the assigned inbound agent answers. A verified number can take both inbound and outbound agent assignments. If the two directions serve different purposes, each can use a different deployed agent configuration.
Typical call flows
Overflow answering
When the primary team cannot take a call, routing on the SignalWire side can send it through the connected trunk to a ThunderPhone inbound agent. The agent follows the deployed prompt to identify the caller's need, answer supported questions, collect details, or route the call. This can form part of an overflow call-handling plan.
Urgent-call routing
An inbound agent can screen the request and follow explicit escalation rules. Where the imported production number is eligible to place an outbound SIP leg, an attended warm transfer can privately brief the recipient before connecting the caller. If the recipient declines, does not answer, or reaches voicemail, the agent can return to the caller with the outcome. Test this path against the live trunk configuration before relying on it for urgent-call routing.
Outbound follow-up
ThunderPhone can place an outbound call through the verified imported number. The outbound agent follows its assigned prompt and configured voicemail policy. Endpoint-based webhooks can notify your server about call events and retry non-successful deliveries; that automation is separate from the SIP connection itself.
Setup outline
- In SignalWire, identify the SIP trunk and number to connect. Confirm the routing and outbound authorization required for the intended call directions.
- Open Connections → VoIP in ThunderPhone, select New connection, choose Connect a provider you already use, then pick SignalWire.
- Create SIP credentials for outbound calls in SignalWire, then enter the SIP domain (for example
your-space.sip.signalwire.com), username and password, plus port and transport if they differ from the defaults. Configure allowed source IPs if your trunk uses an IP allowlist. - In SignalWire, assign each number a SWML script that connects incoming calls to the ThunderPhone SIP endpoint shown on the form. The form links SignalWire's own guide, and Generate AI Setup Guide can write step-by-step instructions.
- Select Test & Save Connection. If it fails, correct the SIP domain, port or transport, or the network path to it, and retry.
- Import the number from Phone Numbers → Add number → Import existing numbers. Its verification call tests the outbound path; if it fails, correct the SIP credentials or outbound settings and verify again.
- Assign the agents, then call the number from any phone to confirm inbound routing; if it does not reach ThunderPhone, check the SWML script assignment and any source restriction. Test inbound and outbound calls, and deploy any pending agent draft before launch.
Keep the SIP credentials and routing current as your provider configuration changes. Telephony charges and number costs remain dependent on the SignalWire setup. Check the current ThunderPhone VoIP screen for the latest steps before beginning.