SIM800L GSM GPRS Module

TTL serial port for serial port, you can link directly to the microcontroller. No need MAX232
Power module automatically boot, homing network
Onboard signal lights all the way . It flashes slowly when there is a signal, it flashes quickly when there is no signal

PinOut :
1.NET = Antena
2.VCC = +3.7-4.2V
3.RST = Reset
4.RXD = Rx Data Serial
5.TXD = Tx Data Serial
6.GND = Ground/0V
7.RING when call incoming
8.DTR
9.MICP = Microphone +
10.MICN = Microphone –
11.SPKP = Speaker +
12.SPKN = Speaker –