Connecting Retell AI to Your Phone Number
Retell does not sell Australian numbers, so bringing your own is the only way to put a Retell agent on a local landline or a 1300 number. Click2Call has a built-in Retell AI connection profile that makes it a one-dropdown job.
Last reviewed: September 2026
At a glance
- Mandatory Click2Call field
- None — just pick the connection type
- Where Click2Call sends calls
- sip:sip.retellai.com;transport=tcp
- Authentication
- IP allowlist on the Retell side — add 103.212.52.19
- Number format
- +E.164, set automatically
- Code required
- No — the agent is built in the Retell dashboard
- Provider documentation
- Retell AI custom telephony
Connecting Retell AI, Step by Step
Build the agent in Retell
In the Retell AI dashboard, create the agent that should answer the phone — prompt, voice, functions and knowledge base. It is all dashboard configuration; there is nothing to deploy.
Import your Click2Call number into Retell
Open Phone Numbers and import your existing number rather than buying one from Retell. Enter it in E.164 format, e.g. +61355551234 — it has to match what Click2Call sends.
This is the whole reason to use bring-your-own-number: Retell does not sell Australian geographic numbers, so importing a Click2Call number is how you get an AI agent answering a local landline or a 1300 number.
Assign the agent to the number
Attach the agent you built as the inbound agent for that number. Until one is assigned, calls arrive at Retell and are not answered.
Click2Call cannot present a username and password on an outbound INVITE, so the provider has to trust us by IP allowlist. Allowlist 103.212.52.19 — that is the address our switch sends INVITEs from. If a provider will only accept authenticated INVITEs, the connection has to run the other way round — the provider registers to Click2Call as the number, which is the generic method in connecting an AI voice agent.
Create the profile in Click2Call
In the Click2Call portal open Voice → Profiles and set Connection Type to Retell AI.
There are no extra fields. The Inbound SIP URI Route line already shows sip:sip.retellai.com;transport=tcp, and the number format is set to +E.164 automatically.
Assign your number, then check the time zone
Open Voice → Line Manager and set the Profile column for your number to the profile you just created.
The Default profile applies to every line with no profile assigned, and new numbers land on it automatically — a number left on Default will ignore everything you just configured. While you are in the profile, set the Time Zone to where the business operates: business hours, after-hours routing and queue schedules all read it.
Test the call
Ring the number from a mobile. The agent should answer, and the call should appear in both the Retell call history and your Click2Call call records.
Troubleshooting
The provider replies 407 Proxy Authentication Required
The provider is challenging our INVITE for a username and password, which means our signalling address is not on their allowlist. Click2Call cannot answer that challenge on an outbound call, so the fix is always at the provider end — allowlist 103.212.52.19 rather than issuing credentials. While this is happening, callers hear “the number you have called is not available from this service”.
The call reaches Retell but no agent answers
The number was not imported in the format Click2Call sends (+E.164, with the plus), or no inbound agent is assigned to it. Check both in the Retell Phone Numbers screen.
Calls are rejected before ringing
Retell is not accepting traffic from the address Click2Call signals from. Ask support for the current addresses and allowlist them.
Calls go to Click2Call voicemail instead
The number is still on the Default profile rather than the provider profile, so the call never leaves for the provider at all. Check the Profile column in Line Manager.
The agent answers but cannot transfer calls
Warm and cold transfers are configured in the Retell agent, not in Click2Call. If a transfer target is another extension on your account, dial it as a full number rather than an internal extension.
Frequently Asked Questions
Do I need to write code?
No. Retell is one of the no-code providers. Compare with OpenAI and xAI, which both need a webhook you host.
Do I have to buy a number from Retell?
No — that is the point of this setup. Retell does not sell Australian geographic numbers, so importing a Click2Call number is how you get an agent on a local landline or a 1300 number.
Are calls still recorded and transcribed?
Yes, provided Recording Enabled is ticked on the profile. Recording, transcription, summaries and sentiment all work as normal on the Click2Call side, stored in Australia and New Zealand. See AI voice tools.
Can I use my existing business number?
Yes — port it across first, then assign it to the profile. Local and mobile numbers typically port in 5 to 10 business days.
Related Guides
Still need help?
Our Australian support team is available to assist you.