inputs.text: lack documentation could not figure interface device purchase sim908 instead - since stm32 microprocessor think must program chip order communicate sim908 card able email sainsmart via website information got back schematics chinese poorly translated english careful purchase sainsmart exact reason sometimes get away zero documentation case really need quick tutorial programming development board someone figures device may worth purchasing dayi returned purchased sainsmart sim908 board able interface device fine rs232 communication 9600 baud w commands see review device information