SIM900A modem giving "ERROR" code

Hi, I am using SIM900A modem to connect to the SERVER. I was able to do with SIM300 modem. Now i am using the same code to connect to the SERVER with SIM900A. But, i couldn't connect it is giving ERROR message

AT+CGEREP

ERROR
AT+CIPMUX=0

ERROR
AT+CREG?

ERROR
AT+CGAAAAAAAAAAs

AT+CGATT=1

ERROR

I am able to use SMS service. What could be the problem?

What could be the problem?

I'm going to guess it is either hardware or software. You posted no details about the hardware except that somehow it includes a SIM900A modem, and you've posted no code, so all we can do it guess.

I hate guessing games.

#include<SoftwareSerial.h>

SoftwareSerial mySerial(9,10); // Rx | Tx
void setGPRS();
void sendGPRS(char ch);
char data[10]=“Namaste!”;
char que[10]=“hw r u?”;
void setup()
{
Serial.begin(9600);
mySerial.begin(9600);
delay(100);
}
void loop()
{
if(Serial.available())
switch(Serial.read()){
case ‘s’: setGPRS(); break;
case ‘d’:sendGPRS(data);delay(3000);
sendGPRS(que); break;
}
if(mySerial.available())
Serial.write(mySerial.read());

}

void setGPRS()
{
mySerial.write(“AT+CGATT=1”);
//Attach a GPRS Service
mySerial.write("\n\r");
mySerial.write(“AT+CGDCONT=1,“IP”,“airtelgprs.com””);
//Define PDP Context
mySerial.write("\n\r");
mySerial.write(“AT+CDNSCFG=“208.67.222.222”,“208.67.220.220"”);
//Configure Domain Name Server. You can use Google public DNS as well
mySerial.write(”\n\r");
mySerial.write(“AT+CSTT=“airtelgprs.com”,”",""");
//Set Access point, User ID, and password
mySerial.write("\n\r");
mySerial.write(“AT+CIICR”);
//Bring up wireless connection with GPRS P.S. Time consuming
mySerial.write("\n\r");
delay(1000);
mySerial.write(“AT+CIFSR”);
// Get Local IP address. No actually needed though.
mySerial.write("\n\r");
mySerial.write(“AT+CIPSTATUS”);
// Get Connection Status P.S. It should be ‘IP STATUS’.
// This can be used as a check point.
mySerial.write("\n\r");
mySerial.write(“AT+CIPHEAD=1”);
// Add headers to the HTTP request.
mySerial.write("\n\r");
mySerial.write(“AT+CDNSORIP=0”);
//Indicates whether connection request will be using IP address (0), or domain name (1)
mySerial.write("\n\r");
mySerial.write(“AT+CIPSTART=“TCP”,“xxx.xx.xx.xxx”,“747"”);
//Start up TCP connection (mode, IP address/name, port) P.S. if returns ‘CONNECT OK’ then you’re lucky
mySerial.write(”\n\r");
mySerial.write(“AT+CIPSEND”);
//Telling the GSM module that we’re going to send the data
mySerial.write("\n\r");
mySerial.write(“sending data from GPRS modem”);
//And finally here comes the actual HTTP request
//The following are the headers that must be set.
mySerial.write("\n\r");
mySerial.write("\n");
mySerial.write((char)26);
//It tells the GSM module that we’re not going to send data anymore
// char ctrlZ = 0x1A;
mySerial.write("\n\r");
}

void sendGPRS(char ch)
{
mySerial.write(“AT+CIPSEND”);
//Telling the GSM module that we’re going to send the data
mySerial.write("\n\r");
delay(2000);
mySerial.write(ch);
//And finally here comes the actual HTTP request
//The following are the headers that must be set.

mySerial.write("\n\r");
mySerial.write("\n");
mySerial.write((char)26);
//It tells the GSM module that we’re not going to send data anymore
// char ctrlZ = 0x1A;
mySerial.write("\n\r");
}