Previously I had my router and wired connection connected to the other of these two rooms and had signal, which makes me think the they are both receiving the same signal from the street. And makes all of this confusing. I assumed the wiring in my house was a single coax coming into the house from the street, hitting a splitter, and room A was one side of it and room B was the other side of it. If that were true, would the connection be working as is? What are you suggesting the wiring looks like instead of that? Are you suggesting there is a splitter and then another splitter, or that they may be coming in from two separate sources off the street (which seems unlikely), or something else?