What is SMSC number

Hi estep0511, we're here to help you with the SMSC number to set up Wi-Fi calling.

The common Message Center Number for new and existing AT&T wireless customers is:

• +1.312.314.9810
• This number is provided on all AT&T SIM cards nationally. 

For more information on setting up Wi-Fi Calling review the following steps.

1. Tap Settings on your phone, then tap Cellular (Apple devices) or Connection (Android devices).
2. Check if Wi-Fi Calling's listed.
   • If it is, select Wi-Fi Calling.
   • If not, your phone isn’t compatible.
3. Review important info and confirm your emergency 911 address.

Let us know if this information helps, and thank you for contacting the AT&T Community Forums.

Jeff, AT&T Community Specialist