GregS wrote:

Its a fact both my cable boxes, are both digital, but only one is HDTV capable.
None have a digital output.

I have yet to see a cable HDTV STB that didn't have either a DVI or HDMI
output. Model?

The idea is also to have all HDTV eventually. I guess one day the digital
channels will go off the air with NTSC bandwidth specs. and only leave digital HDTV ???

Huh? I don't comprehend.

If I select a digital HDTV channel and try to watch it on an old set,
whats going to happen ?? This is with video in, but how about
antenna in ??

"Video in" from a cable box is analog, so it will be OK. "Antenna in" is
also analog if coming from your cable box, or a digital-analog converter
for your antenna.