This may be helpful to others… I signed up for an AT&T developer IoT kit: https://att.m2m.com/devkit/ It comes with 3 SIM’s. To get these working with the MG2639 you’ll need to run a few AT commands that aren’t natively build into the Arduino library:
- Set the APN AT+ZPNUM=“m2m.com.attz”,“”,“”
- Enable Network Registration (I think you need to do this, not 100% sure) AT+CREG=1
- Open the Network Session AT+ZPPPOPEN
I still have yet to figure out how to get a number assigned to the SIM, it may not be possible with the M2M kit from AT&T.