Connect Mitel
Link a Mitel MiVoice Business system to VINSI so AI agents can transfer to your extensions and call out through your own lines.
Created: September 18, 2026
Updated: September 18, 2026
Overview
VINSI connects to Mitel through a SIP trunk between your Mitel system (usually through a MiVoice Border Gateway) and VINSI's Session Border Controller (SBC). Because the dial plan and security have to match on both sides, this connection is set up together with the VINSI team rather than from a form. This page explains what's involved so your Mitel administrator knows what to expect.
What You Can Do
| Capability | Detail |
|---|---|
| Transfer to extensions | AI agents transfer callers straight to a Mitel extension (2 to 6 digits), with hold music while it rings. |
| Call extensions | An agent can place a call to an extension, for example to reach an on-call person. |
| Outbound calls with your caller ID | Optionally, the AI's outside calls go out through your Mitel, so recipients see your company's own number. |
| Encrypted signalling | SIP over TLS between your system and VINSI. |
Callers reach the AI on a VINSI number or a carrier number connected to VINSI. To send your existing main number to the AI, have your Mitel route or forward it to that number. See Connecting Your Phone System for the options.
How It Connects
- The AI agent decides to transfer or dial, for example to extension 2150.
- VINSI sends the call to its SBC, which signs in to your trunk and translates the number into your dial plan.
- Your Mitel receives the call on the trunk and rings the extension, or dials out to the phone network.
Your system only ever talks to VINSI's SBC, at a fixed address you can lock the trunk to. VINSI provides that address during setup.
What VINSI Needs From You
| Item | Example / notes |
|---|---|
| Public address of your SIP peer (MBG) | A public IP address or hostname that VINSI's SBC can reach. |
| Port and transport | TLS on port 5061 is recommended. UDP on 5060 also works. |
| Extension range | For example 2000–2999, and any extensions that should be off-limits. |
| Outside dialling format (if the AI calls out through Mitel) | How your system expects outside numbers, e.g. 9 + 1 + 10 digits. |
| Caller ID to present | The number recipients should see on outside calls. |
| A test extension | An extension someone can answer during testing. |
| A technical contact | Someone who can make trunk changes during the test window. |
What Your Mitel Admin Configures
- A SIP trunk / SIP peer to VINSI's SBC, authenticated by its IP address.
- Direct dial-in to extensions. Calls arriving on the trunk must reach the extension number as sent. If the trunk strips or “absorbs” digits, calls fail with Number Unobtainable.
- Class of Restriction (COR) for the trunk that allows what you want the AI to do — internal calls only, or local and long-distance too.
- Codec G.711 μ-law (PCMU).
- Public addressing on the MBG. The gateway should advertise its public address, not its internal LAN address, in its SIP messages.
- If using TLS, trust VINSI's certificate authority (Let's Encrypt) rather than pinning a single certificate, which renews every few months.
Firewall Settings
Turn off the SIP helper (SIP ALG) on the firewall in front of your Mitel, or use TLS so the firewall can't read the SIP traffic. Firewall SIP helpers — FortiGate's “session helper” is a common one — rewrite call details in flight and cause some calls to have no audio, one-way audio, or to drop after about 30 seconds.
- Allow SIP from VINSI's SBC address on the trunk port (5061 for TLS, or 5060).
- Allow the RTP audio port range your MBG uses, in both directions.
Setup Steps
- Send VINSI the details in What VINSI Needs From You.
- VINSI sends back the SBC address and configures its side of the trunk.
- Your admin builds the trunk, COR and firewall rules above.
- Test together: VINSI rings your test extension; someone answers and confirms two-way audio.
- If the AI will call out through Mitel, test an outside call and check the caller ID shown.
- Add transfers to extensions in your agents (below), then run a live test call.
Using Extensions in Your Agents
Only use extension numbers after VINSI confirms your trunk is live. Extension transfers are switched on per account as part of setup.
Once it is, enter an extension anywhere an agent asks for a transfer destination — just the digits, for example 2150, with no + or area code. VINSI routes any 2–6 digit destination over your trunk. Full phone numbers still go out as normal calls.
See Create an AI Phone Agent for where transfer destinations are set.
Troubleshooting
| Symptom | Usual cause |
|---|---|
| 404 Number Unobtainable when dialling an extension | The trunk is stripping digits, or isn't allowed to dial in to extensions. |
| Some calls have no audio, or audio one way only | A firewall SIP helper is rewriting the call. Turn it off, or switch the trunk to TLS. |
| Calls drop after about 30 seconds | The MBG is advertising its internal address, or a firewall SIP helper is blocking call acknowledgements. |
| Answered calls have dead air | A firewall SIP helper is blocking call set-up messages. Turn it off, or use TLS. |
| 486 busy on outside calls only | The trunk's COR doesn't allow that kind of call (often long distance). |
| Calls stop working right after moving to TLS | Re-associate the TLS connection with the IP-authorised trunk on the Mitel side. |
| No calls get through at all | A firewall or intrusion-prevention rule is blocking VINSI's SBC address. Check allowed and blocked lists on both sides. |