I am setting in my application AT+CMGF=0 (PDU Mode). So I can receive PDU data. I have written all functions to parse PDU data. But after 10 or 12 hours, the mode ia automatically set to 1 (text data). I don't know how this is happening as I am ecpecting only PDu data not text Data and thus my application fails. Why GSM modem is changing its mode automcatically? ANy clue?