I have a VIP 722 set to single mode. It has two cable drops running into it. Downstairs I have a VIP 381 with it's own cable drop. If I unplug the 722, I lose the signal to the VIP 381 downstair. This makes no sense as the 722 is set to single mode. Is there something I am missing? Is there a way to make the VIP 381 not take it's signal from the 722? I feel like an idiot but this is driving me insane.