Virtual serial port
I often have a need for a virtual serial port (RS232); A open source solution can be com0com at GitHub, this project can also be found as test-signed drivers to be used up to Windows 10 version 1607, where Microsoft changed there policy’s on signed drivers. They do still work on a Virtual machine (or Without Secure Boot).
An alternative hardware solution can be to make a loop, of two USB-to-Serial adapters connected via a Null-modem (a crossover connection). This makes use of drivers signed by others. I made the one on the picture for around 265 DKK (36 USD), a bought program like "Virtual serial port" would cost 1019 DKK (140 USD) pr. user, making the choice easy, since it is quite simple to consume a existing serial port on a computer. Note: the prices are from July 2022.
I have created a proof-of-concept program written in C# that can be found here on Github, It is a work in progress, and I am working on, adding an emulator for RS485.