Arduino GPRS Shield SIM900 not working by software

[Ari_Dosky]

i have the same problem and i fixed it :
the problem is the GPRS did not know the SMS service center number, to fixed it use command AT+CSCA="+964750001140" (change number with your mobile service provider), be aware this commad should type in between command AT+CMGF=1 and AT+CMGS="target number",
the code below work great, i am using hardware serial on pin 7,8 first write:

Code: Select all

#include <SoftwareSerial.h>
SoftwareSerial GPRS(7, 8);

 GPRS.begin(19200);               // the GPRS baud rate   
 Serial.begin(19200);             // the Serial port of Arduino baud rate.
 delay(500);

in loop() write:

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GPRS.print("AT+CMGF=1\r");                               delay(1000);      //text mode enabled                
GPRS.println("AT+CMGS= \"+964750713xxxx\"");   delay(1000);    //target number
GPRS.println("AT+CSCA= \"+964750001140\"");     delay(1000);    //SMS service center
GPRS.println("Arduino sent this SMS itself ");        delay(1000);   // type SMS
GPRS.write(0x1A);                                             delay(1000);    // ctrl+z to send SMS                    
GPRS.println();

[Ari_Dosky]

i have the same problem but i fixed it, just use softwate serial and do not forget to type SMS service number before typing target number.. No Sim900 keep baud rate fix and does not change.