### Answer To route inbound calls from Maqsam to Retell, configure your telephony provider's origination settings to point to Retell's SIP server: Retell SIP Server URI:

sip:sip.retellai.com

[(1) ]() Transport Options: - For TCP:

sip:sip.retellai.com;transport=tcp

- For UDP:

sip:sip.retellai.com;transport=udp

- For TLS:

sip:sip.retellai.com;transport=tls

Configuration Steps: 1. On Maqsam's side: Set the origination SIP URI to

sip:sip.retellai.com

(TCP is recommended) 2. Import your number into Retell: After configuring the SIP trunk with Maqsam, import the phone number into Retell via the dashboard or the [Import Number API]() . You'll need to provide: - The phone number in E.164 format (e.g.,

+14157774444

) [(2) ]() - The termination SIP URI from Maqsam (for outbound calls) - Username and password if using credential-based authentication [(1) ]() 3. Bind an agent: Assign your Retell voice agent to the imported number so inbound calls are routed to the correct bot Troubleshooting Tips: - Verify that Maqsam's origination settings correctly point to Retell's SIP server - Check logs on Maqsam's side for any SIP errors - Ensure the phone number format is correct (E.164 with

+

prefix) [(2) ]() If issues persist, check Maqsam's logs and consider opening a support ticket with them to verify the SIP routing configuration.

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] SIP Trunk Outbound Call - No SIP INVITE reaching my server](https://community.retellai.com/t/sip-trunk-outbound-call-no-sip-invite-reaching-my-server/760) ​

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