Andy Green wrote: > On GTA01 IIRC and certainly 02 there is a) what claims to be some kind > of logical on / off switch in the form of an NPN transistor that goes > into the GSM chipset,
This is quite literally the "on" button of the GSM subsystem. That chipset is designed to be an entire feature phone, so you wouldn't have that additional MCU. In this sort of standalone configuration, PWON (which is where our NPN connects) would just be wired to the phone's power button. - Werner
