For GSM the baseband code is always closed. It is often loaded into the module. Part of a modular approval for PTCRB (as well as FCC/CE) is that the end user ca

For GSM the baseband code is always closed. It is often loaded into the module. Part of a modular approval for PTCRB (as well as FCC/CE) is that the end user can't change the power and radiation profile of the device. This is one reason why the source is closed. What you'd normally care about is the protocol to talk to that baseband. 9/10 for M2M applications it is the 3GPP AT Commands and PPP therefore you can pretty much use PPP dialer to talk to it.