That's it ! I guess this is what I heard about...
But I'm looking for a simple 2 --> 1 midi controlable fast switch....
I'm modulating randomly some Scope device parameter And I want to disable this with a midi cc in order to modulate the parameter by myself, then enable the random lfo again. All this must work fast : take control for ¼ second, then give it back to random lfo...
A pity there is no modular shell with several midi i/o to create midi switch...
Ooops ! But I could do it by changing the midi channel in a 1 midi i/o modular shell....! One channel for the lfo, another channel for taking control ! I go right away to check if there are some modulable midi channel router modules !
...
Yes ! In BCmodular, of course !

It should work ! Viva el Scope !