UniFi Talk with a Third-Party SIP Trunk

Yes — UniFi Talk officially supports third-party SIP providers: Talk › Settings › System › Third-Party SIP Setup › Add Third-Party SIP Provider, and you can run Ubiquiti’s phones on your own carrier without buying a UniFi Talk subscription at all. Ubiquiti’s own documentation confirms it, and that sentence answers the question most searchers arrive with.

Three caveats decide whether it’s right for you, so they come first. This guide is written by SIPNEX, an FCC-licensed carrier, from the vendor documentation and the field configuration a generic carrier needs.

The three caveats

1. Unlocked phones only. Third-party SIP works exclusively with unlocked UniFi Talk phones — a phone activated on a Ubiquiti Talk subscription is locked to it. The flip side: with your own trunk, no Talk subscription is required.
2. Ubiquiti supports six template providers (Breeze Connect, Deutsche Telekom, easybell, DIDWW, Telnyx, VoIP.ms). Any other carrier works through generic custom fields — but configured at your own risk; Ubiquiti support won’t troubleshoot unlisted providers. That’s what this guide is for.
3. E911 becomes your carrier’s job. Ubiquiti’s per-number subscription normally covers emergency addressing; with a custom trunk, emergency-call compliance shifts entirely to the third-party carrier. Confirm your carrier registers your service address for E911 before cutting over — E911 for VoIP requirements explains what’s mandatory.

Adding the provider

In the Talk application: Settings (gear) › System › Third-Party SIP Setup › Add Third-Party SIP Provider.

Talk’s configuration is a key/value custom-field list (the backend is FreeSWITCH-style). For a generic registration-mode carrier, the fields you’ll add with “Add Field” are:

• proxy — the carrier’s SIP proxy/SBC address
• realm — the auth domain, usually the same as proxy
• username — your SIP auth username
• auth-username — only when the auth ID differs from the username
• password — the account password
• register — true for a credentialed account
• commonly also retry_seconds (e.g. 30) and expire-seconds (e.g. 120)

Then complete the panel: Destination Countries (what the trunk may dial), optionally Handle All Outgoing Calls By Default, your DID Numbers (entered manually in E.164 or imported from a .TXT file), and — required — the IP Address Range of your provider’s signaling/media servers. Apply changes, confirm the provider shows Enabled under SIP Providers, and assign DIDs to users via Users › Manage › Change Number.

NAT and the port 6767 rules

Ubiquiti documents a specific network recipe for third-party trunks:

1. Enable Settings › System Settings › Static Signaling Port so Talk uses fixed port 6767 for SIP signaling.
2. Give your provider your public IP (with :6767 where their portal wants a port) and put their server ranges in the trunk’s IP Address Range list.
3. If your UniFi gateway does the routing, add a port-forward for 6767 (protocol Both) to the console running Talk, plus a firewall rule accepting it — and forward 6767 through any upstream router too.

Ubiquiti publishes no per-trunk codec or DTMF picker for third-party trunks. In practice, carriers that speak G.711 (PCMU/PCMA) with RFC 2833 DTMF — the defaults on a SIPNEX trunk — are what community integrations run; if a carrier requires exotic settings, Talk is the wrong PBX for that account.

Is Talk the right PBX for a carrier trunk?

UniFi Talk’s appeal is the ecosystem: phones, console, and network under one controller. Its trade-off is configurability — a custom-field list instead of the trunk controls a 3CX, Yeastar, or FusionPBX exposes. For a small office already living in UniFi, a carrier trunk into Talk is clean and subscription-free. For call-flow depth — queues, complex routing, dialers — pair the same trunk with a fuller PBX platform instead.

Frequently asked questions

SIPNEX is an FCC-licensed carrier providing SIP trunks for any PBX or phone system — registration-mode credentials that drop into Talk’s custom fields, E911 registration on your DIDs, and A-level STIR/SHAKEN attestation. Connect your system or see rates.