I'll tell you what worked for me, because I didn't foundfind the schematicschematics of this board. But your board may work differently, so it is always good to check the datasheet and the schematic (if you have one).
#include <SoftwareSerial.h>
SoftwareSerial GPRS(7, 8); //7 = TX, 8 = RX
unsigned char buffer[64]; port
int count=0;
int i = 1; //if i = 0, send SMS.
void setup(){
//delay(10000);
GPRS.begin(19200); // the GPRS baud rate
Serial.begin(19200); // the Serial port of Arduino baud rate.
Serial.print("I'm ready");
Serial.print("Hello?");
}
void loop(){
if (GPRS.available()){ // if date is comming from softwareserial port ==> data is comming from gprs shield
while(GPRS.available()){ // reading data into char array
buffer[count++]=GPRS.read(); // writing data into array
if(count == 64)break;
}
Serial.write(buffer,count); // if no data transmission ends, write buffer to hardware serial port
clearBufferArray(); // call clearBufferArray function to clear the storaged data from the array
count = 0; // set counter of while loop to zero
}
if (Serial.available()) // if data is available on hardwareserial port ==> data is comming from PC or notebook
GPRS.write(Serial.read()); // write it to the GPRS shield
if(i == 0){
GPRS.print("AT+CMGF=1\r"); //sending SMS in text mode
Serial.println("AT+CMGF=1\r");
delay(1000);
GPRS.print("AT+CMGS=\"+554988063979\"\r"); // phone number
Serial.println("AT+CMGS=\"+554988063979\"\r");
delay(1000);
GPRS.print("Test\r"); // message
Serial.println("Test\r");
delay(1000);
GPRS.write(0x1A); //send a Ctrl+Z(end of the message)
delay(1000);
Serial.println("SMS sent successfully");
i++;
}
}
void clearBufferArray(){ // function to clear buffer array
for (int i=0; i<count;i++){
buffer[i]=NULL; // clear all index of array with command NULL
}
}
