GSM module connectivity issue

Hardware Arduino GSM Shield
1

Hey everyone,

I'm trying to send my first SMS message via Arduino and GSM module, but so far I wasn't successful.
What I have done:
Connected Arduino TX0 to GSM module RX0 and Arduino RX0 to GSM module TX0. Also connected their GND. Tried without connecting Arduino GND to GSM module GND, same issue.
GSM module connects to network (not internet, but you understand) as the indicator blinks every 3 seconds.
There is no pin code for the SIM card and card itself is active: I'm able to send messages when it is inserted in my phone.
I've uploaded this test code from official Arduino website:

/*
 SMS sender

 This sketch, for the Arduino GSM shield,sends an SMS message
 you enter in the serial monitor. Connect your Arduino with the
 GSM shield and SIM card, open the serial monitor, and wait for
 the "READY" message to appear in the monitor. Next, type a
 message to send and press "return". Make sure the serial
 monitor is set to send a newline when you press return.

 Circuit:
 * GSM shield
 * SIM card that can send SMS

 created 25 Feb 2012
 by Tom Igoe

 This example is in the public domain.

 http://www.arduino.cc/en/Tutorial/GSMExamplesSendSMS

 */

// Include the GSM library
#include <GSM.h>

#define PINNUMBER ""

// initialize the library instance
GSM gsmAccess;
GSM_SMS sms;

void setup() {
  // initialize serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  Serial.println("SMS Messages Sender");

  // connection state
  boolean notConnected = true;

  // Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes
  while (notConnected) {
    if (gsmAccess.begin(PINNUMBER) == GSM_READY) {
      notConnected = false;
    } else {
      Serial.println("Not connected");
      delay(1000);
    }
  }

  Serial.println("GSM initialized");
}

void loop() {

  Serial.print("Enter a mobile number: ");
  char remoteNum[20];  // telephone number to send sms
  readSerial(remoteNum);
  Serial.println(remoteNum);

  // sms text
  Serial.print("Now, enter SMS content: ");
  char txtMsg[200];
  readSerial(txtMsg);
  Serial.println("SENDING");
  Serial.println();
  Serial.println("Message:");
  Serial.println(txtMsg);

  // send the message
  sms.beginSMS(remoteNum);
  sms.print(txtMsg);
  sms.endSMS();
  Serial.println("\nCOMPLETE!\n");
}

/*
  Read input serial
 */
int readSerial(char result[]) {
  int i = 0;
  while (1) {
    while (Serial.available() > 0) {
      char inChar = Serial.read();
      if (inChar == '\n') {
        result[i] = '\0';
        Serial.flush();
        return 0;
      }
      if (inChar != '\r') {
        result[i] = inChar;
        i++;
      }
    }
  }
}

Compilation and upload was successful.

I open serial monitor and all I see is:

SMS Messages Sender

I've waited for more than 15mins, but nothing else shows up.

Is there something I'm doing wrong? Any ideas are appreciated.

Many thanks in advance! :slight_smile: