My TiVo 4 kept losing its connection with the tuning adapter and I had to unplug the TA power to reset it. I had a Spectrum tech here for another reason, so he also installed a new Cisco STA1520 tuning adapter. Could not get any channels. After an hour spent on the phone with Spectrum tech support they told him to split Cable In and hook up one line RF line to the TiVo box and the other to the tuning adapter. They said it would communicate via the USB cable. It worked but neither of us knows why. Do you?