I have been looking for GSM modules and found some very interesting devices, such as the SIMCOM 7100C and similar.
The "problem" I have with these is that they are very high-level, that is, you can directly connect an LCD display or a keypad to it and it even includes some ARM processor.
I have been thinking, the "core" functionality of these modules must be available in some simple integrated circuit. I have on SIMCOM's website that the 7100C is built around Qualcomm MDM9215. But I couldn't find much about it.
- What do I look for (what are these ICs called)?
- How would one go about building a GSM solution such as the SIMCOM's IC?