I posted earlier about Tivo/ZenHD520/Directv connection. Couldn't get channel changer to work etc after hooking up Tivo. Turns out after many discussions with Tivo/Zenith/Directv, HD520 and Tivo are not compatible. They will not work together and no one has an answer to how to fix it. Seems they have all accepted it won't work and that is that. No remote code available for Tivo remote to work with the HD520. It is extremely frustrating that people that sell this stuff don't tell you in advance or have the knowledge needed to allow you to make a good decision on what to buy. Only concerned about the sale.