peterr@utcsrgv.UUCP (Peter Rowley) (02/09/84)
I've been told that some TV's (and, I assume VCR's) can descramble
encoded pay TV channels due to an interaction between one scrambling method
and one picture reception improvement method.
The scrambling method is the suppression of horizontal sync information
(the picture tears horizontally, as if the horizontal hold were badly
adjusted). The picture improvement method is sync regeneration; to
get a better sync signal (I assume) some sets regenerate the horiz. sync
from other signals. This, very directly, defeats the scrambling scheme.
On the subject of cable-ready VCR's/TV's, there's one aspect that hasn't
been mentioned-- provision for pay TV services. Some have complained on
the net that the convertors in the cable-ready sets are useless with
pay TV systems that use scrambling as a security method (as opposed to
filtering, which cable-ready sets work fine with). Sony has a solution
to this in a few new TV's and in the SL-2710 Beta Hi-Fi VCR. They have
an AUX position on the tuner, which feeds the cable signal back out of the
set, to an external decoder, and then back in. On the 2710, here's how it
looks:
---------------------------------------- SL2710
| |
cable in --->|--->switch------>tuner--->video |
| | ^ |
-------|------------|-------------------
| |
--->decoder---
The tuner can be set to all the normal cable channels, in which case the
signal goes straight across. One setting, however, diverts the signal
down and out of the VCR to an external decoder, routes it back in, and
then receives that RF signal on a preprogrammed channel (often channel
2 or 3). For more details, see the 2710 owner's manual. This feature is
actually advertised as allowing you to record close captioned material;
Sony did not, I suppose, want to suggest that you put your VCR anywhere near
a descrambled pay TV signal lest you infringe someone's copyright (and
I certainly do not suggest this either; copyright IS a serious business
and I am constantly amazed by the cavalier attitude otherwise law-abiding
and moral people have to it). Nice to see the manuf's making things more
convenient for use with cable systems-- this is esp. useful in Canada
where something like 80% of homes are wired or connected (I forget which).
p. rowley, U. Toronto