Does PowerCinema 6 support "set-top box" to watch DTV?

Yes, but PowerCinema 6 does not support full control for the “set-top box”. This means you cannot select set-top box channels through PowerCinema. Instead, you have to install a TV tuner card (either analog or hybrid) and then connect the set-top box with the TV tuner card via composite or A/V connector. To select a channel, you have to use the remote control of your set-top box rather than using PowerCinema.
To watch DTV, we recommend that you use the TV tuner card that some versions of PowerCinema were shipped with (order with shipped card is recommended).