Twilio

1. Create the trunk, give it a name, and toggle some general settings

2. Setup termination (this is for outbound)

• the termination SIP URI here is important, we would use it in later steps

• For your elastic SIP trunk to accept our outbound request, you need to whitelist IP address or create a auth with username and password.
  • If you opt for the auth route, you need to specify the username and password in the next step when importing the number to Retell.
  • Currently Retell SIP server does not have a static IP, so if you opt for the IP route, you need to whitelist all the IP addresses in the range like following:

3. Setup origination (this is for inbound)

• Here you will specify Retell’s SIP server address as the origination SIP URI: sip:5t4n6j0wnrl.sip.livekit.cloud. If you wish to use toll free numbers, you need to specify sip:5t4n6j0wnrl.sip.livekit.cloud;transport=tcp to use TCP as the transport protocol.

You’ve created the elastic SIP trunk, now you would need to purchase numbers / move existing numbers to this trunk.

Now the number is set up with your elastic SIP trunking, you need to import the number to Retell so that we will know how to route the call.

Here you will supply the termination SIP URI you set up in Step 1. If you have set up auth via credentials, you will need to supply the username and password as well.

You can also import number programmatically via Import Number API.

Now the number is imported, you can make and receive calls with this number just like a number you purchased from Retell — it will show up in your dashboard, and you can make phone calls from Dashboard directly. You can also use the Create Phone Call API to create calls programmatically. If you wish to Retell to stop using this number, you can delete it from the dashboard or via the Delete Number API.