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From: cgordon@vpnet.chi.il.us (gordon hlavenka)
Newsgroups: sci.electronics
Subject: Re: VCR plus + codes  (some listed)
Message-ID: <1991May14.070536.1571@vpnet.chi.il.us>
Date: 14 May 91 07:05:36 GMT
References: <1991May13.124701.11630@ssd.kodak.com>
Distribution: usa
Organization: Vpnet Public Access
Lines: 45

kinsman@ssd.kodak.com writes:
>     . 1-800-4321-VCR salesman says the device
>       fits in your hand.  It requires a code
>       to identify your VCR, and a code to
>       identify your cable decoder box.  Provisions
>       exist to translate the vcr_plus+ selected
>       channel to a new one via a costomer loaded
>       translation table.  Devices retail for about
>       $60 at big chain stores... Sears, Silo,
>       Monkey Ward etc.
>
>     . When are numbers re-used? I still have insufficient
>       data to prove when they get reused... monthly, yearly?

The way I had this explained to me was that the VCR+ knows your cable box and
VCR so that it can produce the proper IR codes to operate them.  This is pretty
obvious.  The way the codes work is that a local FM radio station transmits
the code number and an "on" code at the start of a program, and the same code
number with an "off" code at the end.  The VCR+ contains an RF scanner which
demodulates these codes.  The codes themselves have nothing whatever to do with
the info for the program.

I would guess that the patterns you see are an artifact of the code number
assignment process, rather than a "key" to crack a "code" that probably
doesn't exist.  The numbers will be reused when they get back around to them.

The broadcasts are made by way of an "SCA" (Subcarrier Channel Authorization)
which transmits on an extra sideband of the FM radio program.  Digital infor-
mation can be transmitted without disrupting the normal program material.

My parents live in a small town in Arkansas.  They checked on these boxes and
were told that even though they can get the Little Rock TV stations on their
cable system (They don't have paved roads or running water, but they have
cable!) they cannot use the VCR+ outside of Little Rock because it can't
receive the FM radio station which carries the SCA.

DISCLAIMER:  All the information I have related here is thirdhand.  That means
you are getting it fourth hand.  Treat it accordingly.  I do not use the VCR+
and so I have no experience with it myself.


-- 
-----------------------------------------------------
Gordon S. Hlavenka            cgordon@vpnet.chi.il.us
Disclaimer:                Yeah, I said it.  So what?