efcom v1.2 shield not communicating (Arduino & GSM/GPRS)

Question

I have it connected as described in the official website ELECFREAKS EFCOM V1.2

I use Arduino 1.0.5, upload the example code in the link above, turning the SIM900 on with the pushbutton, it has connection to the operator (indicated by the short flash every 3 second) and it seems fine.. im just not able to send AT commands, and it seems like im not getting anything back to the computer either...

I see that it is default 19200 8N1, i try to send commands in Serial monitor in Arduino 1.0.5, and SSCOM3.2 (linked from page above) and I disable auto-bauding mode, using "AT+IPR=19200"..

info:

I use Arduino 1.0.5
Arduino UNO R3
Efcom V1.2 (SIM900 GSM / GPRS)
Charger -> 9v - 1A

S_RX (GRPS) -> PIN 3 (Arduino)
S_TX (GPRS) -> PIN 2 (Arduino)
baud = 19200

//ARDUINO CODE
# include <SoftwareSerial.h>

SoftwareSerial mySerial (2, 3);

void setup () {
   mySerial.begin (19200) / / the GPRS baud rate
   Serial.begin (19200) / / the GPRS baud rate
   Serial.println ("begin .....");
}

void loop () {
   if (mySerial.available ())
     Serial.write (mySerial.read ());
   if (Serial.available ())
     mySerial.write (Serial.read ());
}

All works out until i should try the communication via the serial port. It's just no respond..

please see the following video -> http://youtu.be/Yt07S57LIFs

Answer 1

I don't know if you already solve your problem, but I found one solution :-)

I had the same problem that you described. I had no received any response for AT commands. I lost many time searching for one solution, and after read the datasheet of the SIM900, I found the PINs responsable by the TX and RX, they are PIN 9 and 10, respectively. On the "EFcom Shield" there are one way to access those PINs directly. If you look bellow the Shield, you can view the labels RX and TX (located bellow the PINs responsable by NOKIA5110_LCD), in other words, if you use RX instead of S_RX and use TX instead of S_TX everything will work perfectly.

Answer 2

Do you are using the Sim900 library? It has a AT Commands example that do it (send AT commands by serial monitor and receive the answer of the command acourding AT documents.

This is a good way to know if the commands are working.