HAHAHAHAHAHAHAHAHA, Ahmed this is not secret. I just I ma doing a control to get information from a machine and display to computer by serial port. I just using a minimum system microcontroller with AT89C52. The problem that I have there is the same that I have with the small program that I am trying to run, and it is: no send data throught the P3.1 TXD pin to the MAX232, MAX232 is an interface serial device to communicate the computer with my controller. While I do not get signals in TXD pin I can not do nothing more. That's the point. A s I told to Mr. Kumar I think I am not setting correctly the parameters.