### Answer To use your client's Rogers VoIP phone number with Retell AI for outbound calls, you'll need to set up Elastic SIP Trunking (the recommended method) or use the Dial to SIP URI approach [(1) ]() . Elastic SIP Trunking Setup: 1. Configure a SIP trunk with your VoIP provider (Rogers) pointing to Retell's SIP server:

sip.retellai.com

2. Set up the trunk to use TCP transport (recommended) , UDP, or TLS 3. Ensure your firewall allows traffic from Retell's IP ranges:

18.98.16.120/30

,

143.223.88.0/21

,

161.115.160.0/19

4. Configure codecs to include at least one that Retell supports: PCMU, PCMA, or G.722 Import the Number into Retell: Once your SIP trunk is configured, import the number into Retell AI : - Go to Phone Numbers > Import Number in the Retell dashboard - Enter the phone number in E.164 format (e.g.,

+1234567890

) [(2) ]() - Provide the Termination SIP URI - this is your Rogers SIP trunk endpoint that Retell will use for outbound calls [(1) ]() - Add SIP username/password if your trunk requires authentication - Save and assign a Retell agent to handle calls on this number You can also import numbers programmatically via the Import Number API . Once imported, the number will appear in your Retell dashboard and you can make outbound calls using the Create Phone Call API or directly from the dashboard .

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] Telnyx](https://docs.retellai.com/deploy/telnyx) ​

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

### Answer The documentation doesn't specify exact time estimates for SIP trunk setup. However, the process involves: On Rogers/VoIP Provider Side: - Creating/configuring the SIP trunk to point to

sip.retellai.com

[(1) ]() - Setting up authentication credentials if required - Configuring allowed IP addresses (

18.98.16.120/30

,

143.223.88.0/21

,

161.115.160.0/19

) On Retell Side: - Importing the number via dashboard or API - Providing termination URI and credentials [(2) ]() - Binding an agent to the number [(3) ]() The actual import takes moments once you have the SIP trunk details. The bulk of time depends on your familiarity with Rogers' VoIP admin panel and SIP trunk configuration. If you're experienced with SIP trunking, this could take 15-30 minutes. If it's your first time, allow 1-2 hours to work through provider documentation and settings. You must dial calls within 5 minutes of calling Register Phone Call API if using the dial-to-SIP method [(1) ]() , though this doesn't apply to the elastic SIP trunking approach recommended for your use case.

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] Twilio](https://docs.retellai.com/deploy/twilio) [[3] Vonage](https://docs.retellai.com/deploy/vonage) ​

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