GPRS Shield V2.0 cannot connect to network

Good morning,
I have a GPRS Shield V2.0 and arduino uno. I use it with my personal SIM card. I followed the wiki
I compiled and loaded the first sketch:

[code]//Serial Relay - Arduino will patch a
//serial link between the computer and the GPRS Shield
//at 19200 bps 8-N-1
//Computer is connected to Hardware UART
//GPRS Shield is connected to the Software UART

#include <SoftwareSerial.h>

SoftwareSerial GPRS(7, 8);
unsigned char buffer[64]; // buffer array for data recieve over serial port
int count=0; // counter for buffer array
void setup()
GPRS.begin(19200); // the GPRS baud rate
Serial.begin(19200); // the Serial port of Arduino baud rate.


void loop()
if (GPRS.available()) // if date is comming from softwareserial port ==> data is comming from gprs shield
while(GPRS.available()) // reading data into char array
buffer[count++]; // writing data into array
if(count == 64)break;
Serial.write(buffer,count); // if no data transmission ends, write buffer to hardware serial port
clearBufferArray(); // call clearBufferArray function to clear the storaged data from the array
count = 0; // set counter of while loop to zero

if (Serial.available()) // if data is available on hardwareserial port ==> data is comming from PC or notebook
GPRS.write(; // write it to the GPRS shield
void clearBufferArray() // function to clear buffer array
for (int i=0; i<count;i++)
{ buffer[i]=NULL;} // clear all index of array with command NULL
It doesn’t work because I don’t have the good LED Status, I have (64ms On/800ms Off SIM900 does not find the network ).
I have a SIM PIN, I don’t know if it can a problem to connect to network.
Thank you in advance.