sim300

hi
I hv succefully intrfaced sim300 with 89c51
nw m facing a problem while reading a msg
actually for AT and AT+CMGF=1 its working fine, m printing it on LCD
bt when I m sending AT+CMGL="REC UNREAD" there is no respons
I hv return a fucn lyk dis dis comnd

void cmd_ReadUnreadMsg(){


        ES = 0;
        SBUF = 'A';
        while (TI==0);
        TI=0;
        lcd_data('A');

        SBUF = 'T';
        while (TI==0);
        TI=0;
        lcd_data('T');



        SBUF = '+';
        while (TI==0);
        TI=0;
        lcd_data('+');

        SBUF = 'C';
        while (TI==0);
        TI=0;
        lcd_data('C');


        SBUF = 'M';
        while (TI==0);
        TI=0;
        lcd_data('M');


        SBUF = 'G';
        while (TI==0);
        TI=0;
        lcd_data('G');

        SBUF = 'L';
        while (TI==0);
        TI=0;
        lcd_data('L');

        SBUF = '=';
        while (TI==0);
        TI=0;
        lcd_data('=');

        SBUF = '"';
        while (TI==0);
        TI=0;
        lcd_data('"');

        SBUF = 'R';
        while (TI==0);
        TI=0;
        lcd_data('R');

        SBUF = 'E';
        while (TI==0);
        TI=0;
        lcd_data('E');

        SBUF = 'C';
        while (TI==0);
        TI=0;
        lcd_data('C');



        SBUF = ' ';
        while (TI==0);
        TI=0;
        lcd_data(' ');

        SBUF = 'U';
        while (TI==0);
        TI=0;
        lcd_data('U');

        SBUF = 'N';
        while (TI==0);
        TI=0;
        lcd_data('N');


        SBUF = 'R';
        while (TI==0);
        TI=0;
        lcd_data('R');

        SBUF = 'E';
        while (TI==0);
        TI=0;
        lcd_data('E');

        SBUF = 'D';
        while (TI==0);
        TI=0;
        lcd_data('D');

        SBUF = '"';
        while (TI==0);
        TI=0;
        lcd_data('"');

        new_line1();

        ES = 1;

//      return;
}

plz tel me whr m goin wrong
Thank you.....!!