I read about the serial communication from Mazidi's book i saw examples using RI and TI and i understood it, the idea i talk about is when i deal regardless the null modem connection as you said:
I want to write a bit of data from the MC through the serial port of the PC assuming i have the PC software handels using the serial port, when the conection first occurs as i understand that the MC will depend on the RI to detect it recieved a bit of data,isn't it?
but for reading how the MC controller will now which location the PC want to read while there's no lines for address or simply if you want to do that (read from it and it's also a problem for writting :which location to write to) what will you do?
thanks again Andy sorry if i appears stupid but it's my first time to deal with 8051