FYI: Comcast digital TV in Cambridge

[Mark J. Dulcey]

Tom Metro wrote:
> 
> There's not really a good excuse for this, as the industry has (or at 
> least did have) equipment that could provide the channels in the clear 
> while blocking the ones you don't subscribe to. They were known as 
> addressable taps. Instead of having a descrambler in a set top box, the 
> tap out on the pole had electronics to filter out the channels you 
> weren't supposed to get. (This was a step up from the old passive filter 
> system, where a change in your subscription required a guy to climb a pole.)

Addressable taps don't work with digital cable. In the digital feed 
there is not a set frequency for a given channel; many channels are 
multiplexed together. If you blocked a frequency range, it would take 
out some channels that the subscriber is supposed to get along with the 
ones that he is not.