Delphi and serial communication

Hi,
I designed application with Delphi for serial interface. my serial port address is $3F8. when i write number to this address, i can not read my number and 129 appeared. for reading, i write 0 to DLAB.

What you wrote goes to an output register. What you read from the very same address is an input register. They are not the same. Hardware doesn't work like RAM; you can't always get what you want.

You also can't directly access the hardware on 32 bit Windows, and only the 16 bit Delphi 1.0 (for Windows 3.0) even has the Pascal commands to do it.

There are plenty of Delphi components for downloading, or you can simply open the serial port as a file.