Advertisements I didn't think much can go wrong with tuning adapters, but then I had some issues and I wanted to post my findings in case they can help anyone. A) What is a tuning adapter? Apparently, since cable lines are more limited in bandwidth then fiber, some cable companies use a trick to provide more channels then they normally could. The channels they deem to be less popular are delivered using SDV (Switched Digital Video). What this means, is that a part of the cable's bandwidth is set aside to handle these less popular channels. This SDV bandwidth, lets say as a simplistic example, can only hold 50 channels. But the cable company will assign 100 channels to this SDV bandwidth, betting that nobody in a given area will be watching more then 50 of those channels at the same time. So, when a customer wants to watch a particular channel designated as an SDV channel, the tuning adapter sends a request out to your cable company's backend system and it is assigned a free slot of the 50 SDV slots to send the channel to your house. It then tells your tuning adapter what slot your requested channel was placed in, and your tuning adapter then tunes to that slot to watch the requested channel. Everything works fine as long as no more then 50 different channels (of the 100 channels designated as SDV channels) are being watched at the same time - because if a 51st user wants to watch a channel not already in one of the 50 slots of SDV, then that request will be rejected because all the slots are taken. But this rarely happens. B) I also found out (at least with my cable company) that tuning adapters need to be "Authorized". Meaning you need to have your cable company "activate" your tuning adapter via the S/N printed on the tuning adapter before it will work right. Also, Tuning adapters don't need to be "paired" with your tivo (like you need to do with your cablecard), they just need to be added to your cable account properly. C) And this third tidbit is probably the most important thing to know to fix most of the issues you might be having with your tuning adapter. It turns out there is a very specific way to "connect and power on" the tuning adapter to get it to work properly. You might think just plugging it in and connecting it to your Tivo using the USB cable is all that is needed, and sometimes that might seem to work. But I have found that even when the tuning adapter seems to work for the most part, I would then get some channels to not work, then work, then not. But once I actually followed the below simple instructions, all the intermittent problems went away. Just follow these steps to properly add/turn-on your tuning adapter for best results: (this info relates to the CISCO STA-1520 tuning adapter, but might to others as well) 1) Disconnect the USB cable between the Tivo and Tuning adapter 2) Power off the tuning adapter (disconnect power adapter). 3) Power on the tuning adapter (connect power adapter). 4) The green light should start flashing - it is downloading the channel map from your cable companies servers. This can take 1-3 minutes. 5) The green light should eventually stay solid on or may turn completely off. 6) If the green LED turned off, press the button next to it to turn it on and it should stay on. If the green LED is already on solid, then press the button to turn it off, wait 10 seconds, and press the button to turn it back on. 7) At this step the green LED should be solid on. 8) Now connect the USB cable to your tivo. The tivo should display a message that it now sees the tuning adapter, press continue. 9) You should now be able to get all your channels. Believe me, I thought just power cycling the tuning adapter would "reset" it, and it often seems that way works because you can tune into most of the SDV channels. But then I would get random channel failures. And doing the above steps fixed my issues completely.