SIM900A GSM Arduino Development Board w Antenna

The SIM900A Specs: 

1, Size: 

     compact and can be embedded directly into the product. 

2, Power: 

   Board integrated USB-powered interface and linear DC power supply 5-12V can use, it is recommended not to exceed 9V. 

3, communication pin: 

     RXD TXD GND, integrated level conversion circuit, which can be accessed 3.3V 5V microcontroller, RXD TXD pin connected to the microcontroller, TXD RXD pin connected to the microcontroller. 

4, boot pins: 

    PWEN high (3.3 / 5V) power is turned on, if not all the LED is not lit. 

    PWON high (3.3 / 5V) to open the module, if not it can not boot. 

PWEN, when PWON are connected high, the module opens a flickering lantern about 1S, when connected to the network card, module about 3s flashes once, and has been maintained. If she does not blink once 3S, indicating module dropped or shut down, most of this situation is caused due to lack of supply current, please replace the power supply. 

Photos Figure 2 
  (Back: regulator chip and large capacitors, USB power port and network interface) 
5, LED: power indicator, signal indicator module, serial communication instructions. 

6, clamshell SIM card connector with EMI interference circuit. 

7, core board with fixing holes, and auxiliary fixed pin, can be embedded directly into your production were to go, convenient, stable and fast. 

8, RJ45 interface and network transformers with on-board, there is no relationship with gprs module itself is through the device to communicate with, there is a chance we can also try to use.

#define POWEN 10

#define POWON 11

void setup()

{

    pinMode(POWEN, OUTPUT); 

    pinMode(POWON, OUTPUT); 

    digitalWrite(POWEN, HIGH);

    digitalWrite(POWON, HIGH);

    Serial.begin(38400);    //set baud rate to 38400

    delay(10000); 

    Serial.print(" ");

      delay(1000);                  

      Serial.print("AT+CMGF=1 ");    

      delay(1000);

      Serial.print("AT+CMGS="+601xxxxxxxx'"");    //Number to which you want to send the sms

      delay(1000);

      Serial.print("Test SMS - Ehere ");   //The text of the message to be sent

      delay(1000);

      Serial.write(0x1A);

      delay(1000); 

}

void loop()

{

}

https://elementztechblog.wordpress.com/2014/10/10/interfacing-sim900a-gsm-modem-with-arduino/