Receive response from sim900 (connected to pic18f252 micro)

hello
i design a pic18f252 board to connect with a sim900 board. i can send and receive data to/from computer with my picmicro(baud:9600 8N1None).also i can connect ma sim900 module to pc with rs232 serial(baud:9600 8N1None).but when i connect picmicro board to sim900 module and send (AT+0x0D+0x0A) to sim900,H receive AT instead OK.
please help me.
thank you.

try sending it this way "AT\r" and it will respond!

---------- Post added at 06:31 ---------- Previous post was at 06:29 ----------

the response depends on your settings for ECHO back of characters and i guess thats On , so you would recieve

thank you
my program is :
#define LED1 PORTA.B0
#define LED2 PORTA.B1
#define Buzzer PORTB.B4

char receive;
void main()
{
int i=1;
TRISA.B0=0;
TRISA.B1=0;
TRISB.B4=0;
TRISC.B6=0;
TRISC.B7=1;
UART1_Init(9600);
delay_ms(400);
UART1_Write("A");
delay_ms(10);
UART1_Write("T");
delay_ms(10);
UART1_Write("E");
delay_ms(10);
UART1_Write("0");
delay_ms(10);
UART1_Write(0X0D);
UART1_Write(0X0A);
delay_ms(200);
UART1_Write_Text("AT\r\n");
delay_ms(200);

while(i==1)
{ //First while loop
if(UART1_Data_Ready()==1)
{
receive = UART1_Read();
switch( receive ){
case 'O':
case 'K':
LED2=1;
break;
case 'A':
case 'T':
Buzzer=1;
break;
case 'E':
case 'R':
{
Buzzer=1;
DELAY_MS(100);
Buzzer=0;
}
break;
default:
LED1=1;
break;
}
}
}
}

in this case LED1 goes on and micro doesn't get OK.
in correct response LED2 must be On.