Is the 2006 deadline for broadcasting digitally BY 2006 or by the END of 2006?

Is there something in writing or some assumptions of how long they would plan to simulcast the analog signals or is the plan to shut down the analog broadcasts at the deadline? Does a station currently simulcasting switch their DTV back to their original station designation (ie channel 6 simulcasting DTV on 44, now, goes back to 6 in DTV later)?

What does that mean for cable providers? Are they mandated to carry the digital signals? Curious that Comcast is not carrying CBS' DTV. I assume there's some monetary issue there?

2006 ain't gonna happen. Every one except the consumer has failed to hold up their end on this one. Then to make matters worse every one points their finger at every one else. My guess is 2020 but who knows.