What stations still might change Feb 17 anyways.

Garrett Wollman wollman@bimajority.org
Mon Feb 9 21:56:40 EST 2009

<<On Mon, 09 Feb 2009 19:11:46 -0500, Scott Fybush <scott@fybush.com> said:

> Your cable box, as you note, uses a translation table to map those QAM 
> channels for display, and the cable company can (and often does) change 
> that mapping on the fly.

This technology is standardized by the cable industry's R&D
association, CableLabs.  The cable box gets this mapping from a device
called a "CableCARD".  If you look at the back side of a DVR-equipped
Comcast box, you'll likely see a piece of metal screwed down over a
slot in the back of the box labeled something like "M-Card only".
Older TVs with digital tuners have the same slot, but without the
security screws, but the cable companies have done so good a job of
discouraging adoption that most TV manufacturers stopped including
them a few years ago.  TiVo still makes DVRs that include working
CableCard slots.  (An "M-Card" is a kind of CableCARD that can decode
multiple channels at once.)

The digital authorization is tied to the serial number of the device
that the card is plugged into, so even if you have one of those TVs
with a CableCARD slot, you still can't put the card from your STB into
your TV.

Last year, with great fanfare, the cable and consumer-electronics
industries introduced "tru2way", a brand name for digital TVs with the
same sort of interactive two-way interface as modern cable boxes.
(The previous generation of CableCARD-ready TVs had receive-only
interfaces, because the cable companies wanted the two-way capability
built into the set but the TV makers wanted the two-way stuff to
reside entirely in the card.)  Currently, only Panasonic has
tru2way-branded products on the market, and they are only available to
Comcast subscribers in Chicago and Denver.


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