So far tuning adaptors have not been reliable for me. I had 3 bad ones right out of the gate. This one has worked for 6 months and now is flashing yellow. When I originally had trouble with the tuning adaptor Cox was out 6 times. Each time they checked the signal levels, used a new line, tried to reset it. In the end the signal strength was fine. The techs did want to wire the adaptor using the pass thru and each time I told them it should be wired using a splitter. They agreed after I showed them the wiring diagram from Cox using a splitter.
The real fustrating part was that lack of training each new tech had. I don't know how many times they said to me that tuning adaptors only work with TiVos. Each time I had to show them the letter from Cox corp saying that Cox was moving to switched digital and that a Ceton card with tuning adaptor was needed. I even had the RI regional manager tell me on the phone that it does not work with Ceton cards.
In the end the problem was bad tuning adaptors. I guess I will start the process with Cox tech support.