### Answer To connect Retell with a local number using Yeastar as a SIP provider, you can use one of two methods: ## Method 1: Elastic SIP Trunking (Recommended) Set up a SIP trunk in Yeastar and configure your number to point to it, then import that number to Retell. [(1) ]() ## Method 2: Dial to SIP URI If elastic SIP trunking isn't supported or you have a more complex telephony setup, configure Yeastar to dial calls to Retell's SIP server. Retell SIP Server Details: - SIP URI:

sip:sip.retellai.com

- IP block for whitelisting:

18.98.16.120/30

(All regions) ,

143.223.88.0/21

(certain US traffic) ,

161.115.160.0/19

(certain US traffic) Transport methods supported: - TCP (Recommended) :

sip:sip.retellai.com;transport=tcp

- UDP:

sip:sip.retellai.com;transport=udp

- TLS:

sip:sip.retellai.com;transport=tls

Media encryption: SRTP is supported (transport should be set to TLS to use SRTP) . Important note: When using a local VoIP provider, you may need to handle phone number normalization on the Yeastar side (e.g., converting local format to E.164 format like

+1234567890

) using a PBX dialplan or SBC rule. [(2) ]() For detailed setup guides, you can reference the Twilio, Telnyx, or Vonage integration guides as a reference for configuring other SIP trunk providers. [(1) ]()

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] Local VOIP Provider not giving E.164 Format](https://discord.com/channels/1186424376300679209/1444865486499221588) ​

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

@AI Evy i need the detailed steps for configuration for both retell and yeastar

### Answer I don't have Yeastar-specific configuration steps in the available documentation. However, I can provide the Retell AI side of the configuration and general SIP trunk principles that you can apply to Yeastar. ## Retell AI Configuration Steps ### For Elastic SIP Trunking (Recommended Method) *Step 1: Configure Origination in Yeastar (Inbound Calls) * Set Retell's SIP server as the destination for incoming calls: - SIP URI:

sip:sip.retellai.com

[(1) ]() - For TCP transport:

sip:sip.retellai.com;transport=tcp

- For UDP transport:

sip:sip.retellai.com;transport=udp

- For TLS transport:

sip:sip.retellai.com;transport=tls

*Step 2: Configure Termination in Yeastar (Outbound Calls) * Set up the termination SIP URI in your Yeastar system and note the following: [(2) ]() - Specify the termination SIP URI provided by Yeastar - Choose authentication method: IP whitelisting or credential-based authentication Step 3: Import the Number to Retell In the Retell dashboard: - Navigate to the phone numbers section - Initiate the import process and provide: - Termination SIP URI (from Yeastar) - Authentication credentials (username/password) if applicable Step 4: Assign Voice Agent Within the Retell AI dashboard, assign the imported phone number to your AI voice agent. ### IP Whitelisting If Yeastar requires IP whitelisting, use these IP blocks: [(1) ]() -

18.98.16.120/30

(All regions) -

143.223.88.0/21

(certain United States traffic) -

161.115.160.0/19

(certain United States traffic) ### Media Encryption SRTP is supported when transport is set to TLS. --- For the Yeastar-specific configuration steps (creating SIP trunks, configuring routes,

etc.) , I recommend consulting Yeastar's documentation or support, as I don't have detailed Yeastar configuration guides in my sources. Check out these potentially useful sources for general SIP trunk setup patterns: - [Custom Telephony Overview]() - [How to Choose the Right Telephony System in 2024]() Would you like a general answer based on common PBX/SIP trunk configuration patterns instead?

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] How to Choose the Right Telephony System in 2024 | Retell AI](https://www.retellai.com/blog/how-to-choose-the-right-telephony-system-in-2024) ​

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