let me try again. No question about RUTX12, as indicated in your video, the sma-connectors are clearly marked. However as you said in earlier response, there is one connector labelled as "main" and 3 as "aux" in RUTX14. Even if I'm using only one sim, it should still use two antennas for LTE, right? How are you dealing the possible case that the other antenna connector is not terminated properly? (Case: only main antenna connected.) If you have only one sim, it should use the main connector and I assume the correct aux connector next to it, right? How about case two active sim cards? When it is for a reason or another switching to 2nd sim, what antennas is it using? It would make sense to switch to another pair of antenna connectors. (Or even better, allow user to configure which antenna ports are used.) I find several user cases for both options. But then also it would be useful to know, not to quess, which are the correct antenna ports.
Or when you have only one sim, there should not be need to connect all four antennas.
My apologies if this was already explained somewhere, I tried to browse all documentation but didn't find the answer.