### Answer The sources don't define a "non mobile number" case, so here is what is documented about which numbers can send SMS. - SMS (A2P 10DLC) is limited to US phone numbers and excludes toll-free numbers. The SMS add-on is disabled in the dashboard for non-US and toll-free numbers. [(1) ]() - SMS is available for Retell Twilio numbers and custom telephony numbers that have passed A2P applications. Telnyx is not supported yet. - If you only need to send SMS during a call, you can skip the A2P application and send from Retell's pool of SMS-approved numbers instead. The message is a preset Retell template, and it can't be customized or used for two-way SMS conversations. [(1) ]() [(2) ]() - A community report says a Canadian number couldn't send SMS on Retell, with only US numbers supported. [(3) ]() - A community report also says that sending SMS from a custom telephony number wasn't supported at the time, and a custom function was needed instead. [(4) ]() If your number is non-US or toll-free, the SMS add-on isn't available on it. Your options are the SMS-approved Retell number for in-call SMS, or a custom function that sends the text through an external provider. If you tell me what type of number you have (for example, landline, toll-free, or non-US) , I can point to what applies.

​ To learn more, see the sources I considered: [[1] Enable SMS](https://docs.retellai.com/deploy/enable-sms) [[2] SMS Node](https://docs.retellai.com/build/conversation-flow/sms-node) [[3] Discord message from @metaverse55 on 2025-05-30](https://discord.com/channels/1186424376300679209/1186462578310910112/1377919480973361153) [[4] Phone number can send SMS](https://discord.com/channels/1186424376300679209/1387874084536193024) ​

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