Redirect serial port to file

Hello, list!

I need some help in setting up a serial port redirection to a file, that
works from dosemu.

I have an old Dos app that sends data to a serial port only. Because I
do not have an appropriate device to connect to the port, and because I
need to view the output data, I need some sort of low level redirection.
The Dos app should send data to com1 and the data should be written to a
file. Do someone have an idea how to do this?

Thanks and regards,
Lars