I have a SIMCom SIM808 2G GSM module on a custom PCB based upon the Adafruit FONA. I got a bunch of 2G SIM cards from Aeris.net. The problem is when I first put the SIM cards in my device, I get "Registration Denied" (+CREG: 3) and the device will never register with the network. My AT commands and responses look like this;
AT OK SMS Ready AT+CREG=1 OK +CREG: 3 +CREG: 2 +CREG: 0 +CREG: 2 +CREG: 0 +CREG: 2 +CREG: 0 [and on and on for hours...]
Now if I take that same SIM and insert it in an old Samsung Galaxy S5, turn it on and wait a few minutes for the cellular bars to appear, then take the SIM out and put it back in my device, it registers with the network immediately and forever after. It looks like this:
AT OK SMS Ready AT+CREG=1 OK +CREG: 5
It appears that the Android phone is doing some magic to the SIM card or my account that makes the SIM card work in my SIM808. Aeris support can't see the device attempting to register.
What's going on here? What does it take to first register this SIM card from my SIM808? It not going to be possible to first put each card in an Android phone before using with the SIM808.