Connect Twilio (Elastic SIP Trunking)

Overview

A Twilio Elastic SIP Trunk connects your Twilio numbers to VINSI in both directions: Twilio sends incoming calls to VINSI (origination), and VINSI sends the AI's outgoing calls and transfers out through Twilio (termination). The number stays in your Twilio account and on your Twilio bill.

Not on Twilio? See Connecting Your Phone System for the other options.

Before You Start

• A Twilio account with at least one voice-capable US or Canada number.
• A VINSI AI agent to answer the number. See Create an AI Phone Agent.
• Open VINSI's Phone Numbers page and click Add SIP Trunk. The Configure SIP Trunk window shows your Origination SIP URI under Inbound Call Setup — keep it open, you'll need it in step 3.

1. Create the Trunk

1. Log in to the Twilio Console.
2. Find Elastic SIP Trunking in the left menu (or search for it) and click Manage → Trunks.
3. Create a new trunk and give it a name you'll recognise, such as VINSI AI.
4. Under General Settings, turn on Call Transfer (SIP REFER) so the AI can hand calls to your team, and Call Recording if you want Twilio to keep its own recordings.
5. Click Save.

2. Termination (Outbound)

This is the address VINSI uses to send calls out through Twilio.

1. Open the trunk's Termination tab.
2. Choose a Termination SIP URI, for example vinsi-acme.pstn.twilio.com. Note it down — this is the value for VINSI's SIP Termination URI field.
3. Under Authentication, create a Credential List with a username and password, and attach it to the trunk.
4. Click Save.

3. Origination (Inbound)

This tells Twilio where to send calls that come in on your number.

1. Open the trunk's Origination tab and click Add new Origination URI.
2. Paste the Origination SIP URI from VINSI's Configure SIP Trunk window. Keep the sip: at the start.
3. Set Priority to 1 and Weight to 1.
4. Click Add.

4. Add Your Number

1. Open the trunk's Numbers tab and click Add a Number.
2. Pick an existing Twilio number, or buy one. Calls to it now go through the trunk instead of any webhook it used before.

5. Connect It in VINSI

Back in VINSI's Configure SIP Trunk window, fill in:

1. Click Configure Trunk. The number appears in your list.
2. Assign it to an agent. See Setting Up Phone Numbers.

6. Test

• Incoming: call the number from your mobile. The AI agent should answer.
• Outgoing: open the agent and click Call Me to have the AI ring your phone.
• Transfer: ask the AI to transfer you, and check the call reaches the right person.

Each test call appears in Call Logs with its recording and transcript.

Troubleshooting