So should I follow the HowToGuide for BUS intercom where BUS- = R1 and and BUS+ = R2?
As long as I won’t shortcut anything by connecting the wrong wires, I’m not afraid to test.
I guess I can detach one of R1/R2 and ring the bell to see if I have disabled the loudspeaker? And that’s where the red and orange cable should go? And then the black in the other one?