STM32-LCD

STM32-LCD is a development board from OLIMEX and by combination with MOD-GSM from this company you can design/programming your own GSM.

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As you can see to make a real GSM you need a speaker to hear the ringing and a speaker to hear voice and also a microphone to talk that I added it to the modules.

If you like to get more information, please feel free and contact me via contacts page.