​ To learn more, see the sources I considered: [[1] Twilio](https://docs.retellai.com/deploy/twilio) [[2] Import Phone Number](https://docs.retellai.com/api-references/import-phone-number) [[3] Phone number connection error](https://discord.com/channels/1186424376300679209/1428698638938542161) [[4] Retell AI - Connect to your own Twilio - Using Sip Trunking]() ​

### Answer ## Steps to Add a Twilio Number to Retell AI Step 1: Create Elastic SIP Trunking in Twilio [(1) ]() - Create the trunk and give it a name - Setup termination (for outbound calls) - the termination SIP URI here is important - You may want to use a localized termination URI near your region - Whitelist IP addresses or create auth with username and password for your trunk to accept outbound requests - Setup origination (for inbound calls) - specify Retell's SIP server address as the origination SIP URI:

sip:sip.retellai.com

Step 2: Move Numbers to Elastic SIP Trunking - Purchase numbers or move existing numbers to this trunk in Twilio Step 3: Import Numbers to Retell - Supply the termination SIP URI you set up in Step 1 - If you set up auth via credentials, supply the username and password as well - You can import via the dashboard or programmatically via the [Import Number API]() --- ## What is Termination URI? The termination URI is used to uniquely identify your elastic SIP trunk and is used for outbound calls. [(2) ]() For Twilio elastic SIP trunks, it always ends with

.pstn.twilio.com

. , [(1) ]() Example:

someuri.pstn.twilio.com

[(2) ]() Important tips: - Make sure there are no spaces in the URI [(1) ]() - Do not include

sip:

as a prefix [(3) ]() - Copy the full URI including

.pstn.twilio.com

[(4) ]() ---

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.