URGENT! Arduino Uno + ICOMSAT V1.1 GSM Modem Communication

I am going insane with this problem, I have absolutely no idea what the heck is wrong…

I am using Arduino Uno and ICOMSAT V1.1 GSM Module

I used the library that itead provided for GSM Module
(GitHub - MarcoMartines/GSM-GPRS-GPS-Shield: GSM/GPRS & GPS Shield Library for modules using SIM900/SIM908)

I placed the jumpers as seen in the picture,
Here are steps that I did

  1. Plug in 12V/2.5A External Power Supply, and USB Plugin from Computer
  2. Open up Arduino, open up the code, upload onto the Arduino
  3. Then Placed the ICOMSAT GSM Shield onto Arduino
  4. Pressed SIM900 Power Button on GSM Modem to turn on the power
  5. Then Compiled on the Arduino
  6. And Open up the Serial Monitor

and it gives me this freaking error every single time
DB:No Response
Forcing baud rate from 1200-115200,
ERROR: SIM900 doesn’t answer. Check power and serial pins in GSM.cpp

Code I’ve used is shown below

#include “SIM900.h”
#include <SoftwareSerial.h>
#include “sms.h”
boolean started=false;

void setup()
//Serial connection.
Serial.println(“GSM Shield testing.”);

if (gsm.begin(2400)){
else Serial.println("\nstatus=IDLE");

if (sms.SendSMS("+6148123123123", “SMS from Arduino”))
Serial.println("\nSMS sent OK");

void loop()

Somebody please help me…I’ve been working with this problem for 3 days and I have no idea what’s wrong

You bought a shield and used some software from itead. Seems to me the place to get an answer would be itead.

About two thirds down this page:


Is a sketch entitled '//Serial Relay'.

Copy it into the IDE and change the line:

SoftwareSerial GPRS(7, 8);


SoftwareSerial GPRS(3, 2); // RX, TX

Load it up to your Uno, attach the shield, power and USB cable, open the Serial Monitor (19200 baud) and send the command AT (in capital letters) to the Uno. The shield should respond if all is ok.

If not, post your results.