DMX: What should I do with ground and shield?
Generally electrical shielding only works if it is connected to ground (the ground of the stuff its supposed to shield) and the shields of the connectors are connected to the screens/shields in the cables, if they are not connected to signal ground then they do not work to shield the signals properly, but they do not have to be dc-connected you can connect the shield(s) to the signal ground with capacitors.