Originally Posted by RobertWy
My understanding is QAM goes away once your area is converted to all-digital.
Still waiting for the changeover here - so I don't have firsthand experience with the new digital lineup.
However, this changeover will not have any impact on QAM. QAM is the digital format used to broadcast SD and HD channels on the cable.
After the changeover, there will still be some clear QAM channels that can be viewed directly on most HDTVs without a cable STB or DTA. Unfortunately, the only channels that will probably be "clear" will be the same channels you can get over-the-air (OTA) with an antenna.
It is very likely that all (or almost all) of the non-broadcast channels will be encrypted - and will require a cable STB, DTA, or CableCard tuner (such as TiVo or for PCs running Windows Media Center either SiliconDust or Ceton).
The diagram that was shown can be a little simpler if your HDTV has two antenna input ports. If that's the case, the A/B switch can be eliminated and one of the outputs from the 2-way splitter can be connected directly to the HDTV's "Antenna A" or "Antenna B" ports.
It really is unfortunate that Comcast has decided to go this path - because by forcing customers to have a DTA or STB for every TV, they've eliminated what was a major advantage over all of the other competing providers (Dish, DirecTV, AT&T, Verizon Fios, ...) - which have required a box for every TV.
It was extremely convenient to hook your TV directly up to the cable and get the broadcast and "basic cable" channels without requiring an extra box.
Oh well, the price for "progress"...