Hardware switch to switch the software serial pins being "transceived" on.

Charles_Gibbs:
Ok sorry for all the hiccups, I do try to be as precise as I possibly can,

I don't think this is a two-worlds problem at all. You have not responded to confirm or deny my guess as to how the Victron program works.

This has to be a two-way dialogue. I say something, you consider it, you tell me if I am right or correct me if I am wrong. That way I can build up my mental image of the problem and either make a suggestion for a solution or an explanation of why it is not possible.

To follow on from what @dougp has said, I don't think this is a simple multiplexing issue. I think the inputs to the Victron program have to be the sort of thing the Victron programmers designed it to expect. And we have not been told what that is.

...R