Connect 3CX
Put a VINSI AI agent in front of your 3CX phone system — by forwarding calls, or with a SIP trunk for transfers to extensions.
Created: September 18, 2026
Updated: September 18, 2026
Overview
3CX can hand calls to a VINSI AI agent in two ways. Most teams start with call forwarding, which takes minutes and needs no SIP configuration. If you need the AI to transfer callers to 3CX extensions, the two systems are linked with a SIP trunk through VINSI's Session Border Controller (SBC), set up together with the VINSI team.
Choose a Route
| Call forwarding | SIP trunk through VINSI's SBC | |
|---|---|---|
| Setup | Your 3CX admin, a few minutes | VINSI and your 3CX admin together |
| Calls in to the AI | Yes | Yes |
| AI transfers to | Full phone numbers (DIDs, ring groups or queues with a number) | 3CX extensions and phone numbers |
| AI calls out using | A VINSI number | A VINSI number, or your 3CX lines |
| Best for | Getting started, and most receptionist setups | Transfers to many individual extensions |
Route 1: Call Forwarding
Set It Up
- In VINSI, get a number for the agent (Phone Numbers → Add Phone Number) and assign it to the agent. See Setting Up Phone Numbers.
- In the 3CX admin console, set the inbound rule for the number callers dial — or the digital receptionist option you want the AI to handle — to forward to that VINSI number as an external number.
- Call your main number from a mobile and check the AI answers.
Forwarded calls leave 3CX on one of your SIP trunk lines, so they count toward your trunk's simultaneous calls and your carrier's outbound minutes.
Transfers Back to Your Team
The AI reaches your people by dialling a full phone number, not an extension. Give each transfer destination in your agent a number that rings in 3CX: a user's direct number, or a ring group or queue that has its own number.
Don't transfer to the number that forwards to the AI. The call would come straight back to the agent. Use a different number for transfers.
Route 2: SIP Trunk Through VINSI's SBC
3CX connects to VINSI's SBC as a generic SIP trunk. The AI can then transfer to extensions by number — just the digits, 2 to 6 long — and, optionally, make outside calls through your own 3CX lines. This works the same way as the Mitel connection. Contact VINSI to set it up.
What VINSI Needs From You
| Item | Notes |
|---|---|
| Your 3CX public address | The FQDN or public IP of your 3CX, and its SIP port. |
| Extension range | Which extensions the AI may reach. |
| Outside dialling format (if calling out through 3CX) | Any prefix your outbound rules expect. |
| Caller ID to present | The number recipients should see on outside calls. |
| A test extension and a technical contact | For the joint test. |
What Your 3CX Admin Configures
- A generic SIP trunk to VINSI's SBC (VINSI provides the address and sign-in details).
- An inbound rule on that trunk that delivers calls to the extension number that was dialled.
- Outbound rules that allow the calls you want the AI to make, if calling out through 3CX.
- Codec G.711 μ-law (PCMU) on the trunk.
- No SIP helper (SIP ALG) on the firewall in front of 3CX — it rewrites calls in flight and causes missing or one-way audio.
Troubleshooting
| Problem | Check |
|---|---|
| Forwarded calls don't reach the AI | The forward target is the full VINSI number (e.g. +18005551234), and the number is assigned to an agent in VINSI. |
| Transfers loop back to the AI | The transfer destination is the forwarded number. Use a different number. |
| The AI answers but doesn't recognise the caller | 3CX is replacing the caller's number on forwarded calls. Set the forwarding rule to pass the original caller ID. |
| No audio or one-way audio (SIP trunk route) | A firewall SIP helper is rewriting calls. Turn it off. |