Is there anyway to absolutely disable the GPRS ability?

[t0ny-peng]

I only want to use DFRobotSIM808 library to receive message and forwarded to Serial port. I'm using a SIM from another country and the international data is super expensive.

Is it true that if I don't try to sim808.join(F("cmnet"), GPRS will not be activated and no data will be used?

Thanks.