One of my students asked whether his television set, connected to a cable system but with no set-top box, would be able to receive digital television after February 17, 2009.

So I decided to try the experiment of being a consumer with this question.  I was happy to see the NCTA has this site with information about how this will work.  And this:

The good news for cable customers is that the digital transition should be easy.  Thanks to a compromise adopted by the FCC in September 2007, cable companies will carry the main digital signal of “must carry” commercial broadcast TV stations and will duplicate that signal into analog format so that all channels can be viewed on any older analog TV sets connected to cable.

That's putting a bright spin on a mandate that cable systems do the work of transforming digital broadcast signals into analog so that a majority of the people with cable subscriptions will be able to continue to watch all of their local broadcast stations on analog TVs until at least 2012.  (I'm not sure whether cable systems will be allowed to charge for offering the analog version of the digital signal.)  Also, see the words "main digital signal"?  The FCC agreed to allow cable operators to remove sub-channels from the broadcasters' digital signal so as to allow as much compression of the signal as possible. 

But if you're not connected to cable this could be tricky.  The first converter box has been approved [site requires free registration], but it costs $69.99.  Lots of hearings are scheduled to examine how on earth consumers will hear about the digital transition and be allocated vouchers for these boxes.

Why are we going through all of these conniptions with broadcast, when the broadcasters themselves realize that they won't survive unless the cable systems carry their signals?  When their sub-channels won't be carried? And when broadcasting is becoming just a subset of online content anyway?

The answer is that over-the-air television is free (in that you don't have to pay a subscription fee, even you do have to spend time watching the ads), and no one wants to be the politician who strands people without a television signal.

Soon we'll all be in virtual Google-worlds...