It depends on what your cable service is. If Comcast has not encrypted the Local/Basic channels in your area, then you can hook up the cable as before (assuming that the OTA tuners will handle clear QAM) for those channels. For channels above Local/Basic (which are all encrypted) you have to go through a Comcast box and then your other equipment via what ever the box allows you to use for outputs (and yes, only one channel at a time, two boxes two channels, etc.). If the only output of the Comcast box is RF (which will be an analog signal on channel 3 or 4) and you also want the clear QAM (if available) to feed a device you would either need two RF inputs to the device or an A/B switch (which should be available at your local Comcast store for no charge including a one to two splitter and a cable or two).
Sorry if this is a stupid question. I have had cable internet for years but just got digital cable TV. The dest top box they sent is a simple box with a remore. Before cable, I used a digital antenna connect with a coax cable, running through two DVD recorders with builtin tuners, then into the TV. I could record 2 shows at once while watching a third.
Do I understand the settup correctly, that the cable has to go to cable box first, and I cannot hook the cable directly to my TV or to the DVD recorders and record something different than the channel that is selected on the cable box? If I want to record a show, the DVD record would have to be on channel 3 (like the TV), with the cable box on and on the channel I want to record, and there is no way to watch one channel while recording a second? Am I stuck getting a DVR cable box to record something while watching something else?