Phone for Voice Connections
Dial your voice agent's phone number from a Confident AI number or your own SIP trunk.
Overview
Use the Phone transport when your voice agent answers a phone number. Confident AI dials the number over the public telephone network, either from a Confident AI number or through your own SIP trunk.
Phone Number
Enter the number your agent answers in international format, with its country code (for example +1-415-555-0100). Confident AI stores it without the dashes.
Carrier
The Carrier decides which trunk places the call onto the phone network:
- Confident numbers (default): calls go out from a number Confident AI owns. There's nothing else to set up.
- Your SIP trunk: calls leave through your own carrier, so they bill to your account and your agent sees one of your numbers as the caller.
Your SIP Trunk
When you pick Your SIP trunk, fill in the following:
| Field | Description |
|---|---|
| Trunk address | Your carrier's SIP termination URI, for example sip:acme@acme.pstn.twilio.com. |
| Caller ID | A number on your trunk to call from. Your agent sees this as the caller. |
| Trunk authentication (optional) | Turn on and enter a Username and Password if your trunk uses digest credentials. Leave it off if your trunk allowlists by IP instead. |
| Media encryption | Whether the call audio is encrypted with SRTP. See Media Encryption for what each option does. |
The trunk is reached over UDP by default. Use a sips: trunk address to connect over TLS, or add a ;transport= parameter (udp, tcp, or tls) to choose the transport yourself.
Testing Your Connection
Click Dial in the Test call console. The console shows Dialing… and then Ringing… while it waits for your agent to pick up, for up to the connection's Ring timeout. See Testing Your Connection for what each result means.
Next Steps
SIP
Call your agent's SIP address directly, skipping the phone network.
Multi-Turn Evals
Run multi-turn evaluations against your voice connection.
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