DTMF decoder with GSM shield sim900 problem .. plz help me

hay all ;

iam using leonardo board +Gsm shield sim900 + MT8870 decoder board to control some motors

but i can’t enable DTMF detection on GSM shield in my code …

my my project is calling GSM shild sim number then it answer automatically so i send no to GSM that come out to DTMF throw phone port

when i use head phone to hear sound come from it i here tone but all no is the same tone … GSm can’t detect DTMF tone

i found this code recently but i can’t understand it !!

#include “SIM900.h”
#include <SoftwareSerial.h>
//We don’t need the http functions. So we can disable the next line.
//#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
//this code is based on the example of Arduino Labs.

//Simple sketch to detect DTMF tones during a call

//We have to create the classes for calls.
CallGSM call;

char number[20];
byte stat=0;
int value=0;
int pin=1;
char value_str[5];
char DTMF_char=’_’;
int count=0;

void setup()
//Serial connection.
Serial.println(“GSM Shield testing.”);
//Start configuration of shield with baudrate.
//For http uses is raccomanded to use 4800 or slower.
if (gsm.begin(9600))
else Serial.println("\nstatus=IDLE");
//Enable DTMF detection for SIM900

void loop()
//Chekcs status of call
//If the incoming call is from an authorized number
//saved on SIM in the positions range from 1 to 3.
Serial.println(“Pick Up”);
for (int k=0; k<100; k++)



It look to me that the shown code will try to decode incoming DTMF. If this is correct then you need to sendt theese code from external source (like another DTMF-koder or a telephone) https://www.google.no/search?q=tastafon&tbm=isch&tbo=u&source=univ&sa=X&ei=MeDqUtjULYXpywOw_YCwCQ&sqi=2&ved=0CC0QsAQ&biw=1120&bih=570#facrc=_&imgrc=xqpmhvXiTrgadM%253A%3BzcZc8sT2BCdQ5M%3Bhttp%253A%252F%252Fhome.broadpark.no%252F~ajsolli%252Ftastafon.jpg%3Bhttp%253A%252F%252Fhome.broadpark.no%252F~ajsolli%252Ftastafon.htm%3B493%3B481

iam using another mobile to call GSM and send no (1,2,3,4,5,5,6,7,8,9,0,*,#)

i want GSM shield to understand theses no and send it to dTMF decoder

Hi, our SIM900 mounted in our breakout have the DTMF function included. You don't need to use 8870. Not all SIM900 have this function. I hope that is could be helpful for you

http://store.open-electronics.org/Breakout/GSM%20Breakout http://www.open-electronics.org/tag/gsm-shield/