Hi,

At first thanks to s.dinah for sharing the quite helpful file. I had to modify it so it fits my needs (communication with a measurement device using different computers).
Changes made are:
  • Userform added to select COM Port as needed
  • use of global variables to make calls from other userforms
  • separation of "read" from "connect", as I ran into difficulties with the global variables.


Sample.xlsm

But now I ran into issues I can't keep up with. The device I need to connect to uses the Xon/Xoff protocol and I have no clue.

As far as my understanding goes the device is listening all the time providing Xon. While receiving and processing it turns Xoff.

So how can I recognize if the device is in Xon or Xoff state so i can start an automated process using serveral commands depending on each other?

Thanks for any hint or code snippets