regarding GSM 300

i am able to send msg from gsm to the mobile phone but am not able to receive data from the GSM.
eg..in this code when i send AT to the gsm , i get garbage value on the LCD instead of OK..but with the hyperterminal, the communication is proper with both the 8051 and GSM.
and please talk politely . you guys talk very roughly if any one asks question...that is my request to you...

#include<stdio.h>
#include<at89x51.h>
#define port P1
#define dataport P2 // Data port for LCD
sbit rs = port^2;
sbit rw = port^3;
sbit en = port^4; int p; unsigned char msg[20];
//generates delay in milli seconds
void delay_ms(unsigned int i)
{ unsigned int j; while(i-->0) { for(j=0;j<500;j++) { ; } }
}

void command(unsigned char dost) { dataport=dost; //put the value on pin rs=0; rw=0; en=1; //strobe the enable pin delay_ms(5); en=0; }

void lcddisplay(unsigned char word) { dataport=word; //put the value on pin rs=1; rw=0; en=1; //strobe the enable pin delay_ms(5); en=0; }

void lcd_data_string(unsigned char *str) // Function to display string on LCD
{ int i=0; while(str[i]!='\0') { lcddisplay(str[i]); i++; delay_ms(1); } return;
}

//Function to initialize RS232 Serial Port
void serial_init()
{ SCON=0x50; //setup for 8-bit data TMOD=0x20; //setup timer 1 for auto-reload TH1=0xfd; //Baud Rate 9600 TL1=0xfd; TR1=1; //turn on timer 1 TI=1; //indicate ready to transmit
}

//This function displays a null-terminated string on the RS232 port
void send_serial(unsigned char *s)
{ while(*s!=0x0)
{ SBUF=*s;
while(!TI)
{ }
TI=0;
s++;
} }

int i;

void tx0(unsigned char x) //send data to serial port 0
{ EA=0;
SBUF=x;
while(TI==0);
TI=0;
EA=1;
} void lcd()
{ command(0x38); // For using 8-bit 2 row LCD delay_ms(1); command(0x0F); // For display on cursor blinking delay_ms(1); command(0x80); // Set the cursor on first position of LCD delay_ms(1);
} char receive(void) { // unsigned char m; while (RI != 1) {;} //wait to receive data

msg[++p]=SBUF; // save value of data RI=0; return (msg[p]);

}

void main()
{ p=(-1);
delay_ms(80);
lcd();
delay_ms(50);
serial_init(); //Initialize Serial port.

while(1)
{ int m;
send_serial(" AT");
tx0(0x0D);

m=receive();
command(0x06);
lcddisplay(m);

}
}