What does this program send to the com port?

Question

C++ / C#

There is a program Signur232.exe
https://goo.gl/Qet54h
It sends a signal to the selected com port and displays the data. How can I find out what she sends?
Go through the disassembler - but here I won’t see
much Install some kind of com port emulator and see the request (but again - most likely the program will see that there is no device and will not send data, although it can send it in any case, and in case of refusal it will write error - that's what the calculation is)
There is a virtual com port. I can connect the program to it and get the values. How can you find out what she sent and what she received?

Answer 1

You need to install a com port splitter and redirect the duplicated output to a file or connect to it with a terminal.
something like this software: serial-splitter .