SIM800C Development Board GSM GPRS Module Support Message bluetooth TTS DTMF Quad-band

Schematic: http://myosuploads3.banggood.com/products/20181127/20181127000501SIM800CV2.pdf Overview: SIM800C is a quad-band GSM / GPRS module, its performance very stable, with small appearance and high cost-performance, to meet the various needs of customers. The operating frequency of SIM800C is GSM / GPRS 850/900/1800 / 1900MHz, can be used worldwide, you can achieve low power consumption of voice, SMS and data transmission, can be applied to a variety of design requirements of compact product. Features: 1. Input voltage range 5V-18V DC; 2. Self-propelled SIM card slot design, support 2G / 3G / 4G card or small card; 3. Module will connected to the network automatically after you power on it; 4. Compatible with a variety of single-chip serial port; 5. Reserved headset and microphone interface; 6. Support TTS DTMF function; 7. bluetooth 3.0 protocol, enhanced bluetooth antenna, support for serial port SPP and audio services; 8. Reserved lithium battery-powered BAT interface, you can use 3.7V lithium battery or 18650 lithium battery; 9. Reserved IPEX interface, SMA interface, spring antenna interface, can be used on different occasions; 10. With work indicator: the LED will flash 1 time per second when no network, no SIM card or SIM card inserted, and will flash 1 time per 3 seconds under normal conditions. 11. Board size: 40.9*51.3mm Interface description: GND: Power ground VCC_IN: Power supply pin, input DC5V-20V RI: Ring indicator DTR: Data terminal preparation TXD: TTL serial port transmission RXD: TTL serial port receive U2_R: module serial port 2 receive U2_T: module serial port 2 send transmission V_M: connect to the core voltage (5V/3.3V,it depend on your MCU) of MCU for level match(generally, NC also be OK for this pin) ADC: ADC detection SPP: Audio output positive SPN: Audio output negative MC-: Audio input negative MC +: Audio input positive PWR: Power enable or disable(enable when low level) BAT: lithium battery input pin, 3.3v-4.4v Basically instructions: The SIM800C mainly controlled by AT commands, so just find a USB convert to TTL serial port module,and 5V,GND,TXD,RXD pins connect to VCC_IN, GND,RXD, TXD pins of SIM800C When the module is started, the indicator LED flashes once every 1 seconds, and after a period of time, the indicator LED flashes once every 3 seconds, it means the SIM800C start works normally. Package included: 1 x SIM800C Development Board 1 x Antenna 2 x normal pin