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Author Topic: SIM900 - Problems with GPRS Connection  (Read 1701 times)
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Leipzig(Germany)
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Hello,

I have an Arduino Mega, Ethernet Shield and a IComSat SIM900-Shield.
I can send SMS with the module but I can't connect with GPRS.

I'm not sure but I think after the command "AT+CIICR" the module give no "OK"

I already changed the sim-card (t-mobile // blau.de // congstar).

The source code should be okay.

OUTPUT:
GSM Shield testing.
DB:NO RESP
DB:ELSE
DB:ELSE
DB:CORRECT BR

status=READY
DB:STARTING NEW CONNECTION
DB:APN OK
status=ERROR

ERROR
DB:NOT CONN
DB:NOT CONN
DB:NOT CONN

Number of data received:
0

Data received:

code
Code:
#include "SIM900.h"
#include <SoftwareSerial.h>
#include "inetGSM.h"
//#include "sms.h"
//#include "call.h"

//To change pins for Software Serial, use the two lines in GSM.cpp.

//GSM Shield for Arduino
//www.open-electronics.org
//this code is based on the example of Arduino Labs.

//Simple sketch to start a connection as client.

InetGSM inet;
//CallGSM call;
//SMSGSM sms;

char msg[50];
int numdata;
char inSerial[50];
int i=0;
boolean started=false;

void setup()
{
  //Serial connection.
  Serial.begin(9600);
  Serial.println("GSM Shield testing.");
  //Start configuration of shield with baudrate.
  //For http uses is raccomanded to use 4800 or slower.
  if (gsm.begin(2400)){
    Serial.println("\nstatus=READY");
    started=true;
    gsm.forceON();
  }
  else Serial.println("\nstatus=IDLE");
  
  if(started){
    //GPRS attach, put in order APN, username and password.
    //If no needed auth let them blank.
    if (inet.attachGPRS("internet.t-mobile", "t-mobile", "tm"))
      Serial.println("status=ATTACHED");
    else Serial.println("status=ERROR");
    delay(1000);
    
    //Read IP address.
    gsm.SimpleWriteln("AT+CIFSR");
    delay(5000);
    //Read until serial buffer is empty.
    gsm.WhileSimpleRead();
  
    //TCP Client GET, send a GET request to the server and
    //save the reply.
    numdata=inet.httpGET("www.google.com", 80, "/", msg, 50);
    //Print the results.
    Serial.println("\nNumber of data received:");
    Serial.println(numdata);  
    Serial.println("\nData received:");
    Serial.println(msg);
  }
};

void loop()
{
  //Read for new byte on serial hardware,
  //and write them on NewSoftSerial.
  serialhwread();
  //Read for new byte on NewSoftSerial.
  serialswread();
};

void serialhwread(){
  i=0;
  if (Serial.available() > 0){            
    while (Serial.available() > 0) {
      inSerial[i]=(Serial.read());
      delay(10);
      i++;      
    }
    
    inSerial[i]='\0';
    if(!strcmp(inSerial,"/END")){
      Serial.println("_");
      inSerial[0]=0x1a;
      inSerial[1]='\0';
      gsm.SimpleWriteln(inSerial);
    }
    //Send a saved AT command using serial port.
    if(!strcmp(inSerial,"TEST")){
      Serial.println("SIGNAL QUALITY");
      gsm.SimpleWriteln("AT+CSQ");
    }
    //Read last message saved.
    if(!strcmp(inSerial,"MSG")){
      Serial.println(msg);
    }
    else{
      Serial.println(inSerial);
      gsm.SimpleWriteln(inSerial);
    }    
    inSerial[0]='\0';
  }
}

void serialswread(){
  gsm.SimpleRead();
}
« Last Edit: November 26, 2012, 11:49:55 am by n17r0m » Logged

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I have had the same problem. It was solved changing gsm speed to 9600 (according to gsm.cpp)
gsm.begin(9600)
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