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Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!petrus!karn
From: karn@petrus.UUCP
Newsgroups: net.video,net.tv
Subject: Re: CATV: "Addressable" Channels
Message-ID: <269@petrus.UUCP>
Date: Mon, 28-Jan-85 12:39:20 EST
Article-I.D.: petrus.269
Posted: Mon Jan 28 12:39:20 1985
Date-Received: Tue, 29-Jan-85 07:11:28 EST
References: <1486@ritcv.UUCP> <297@terak.UUCP>
Distribution: net
Organization: Bell Communications Research, Inc
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Xref: watmath net.video:925 net.tv:2347

> Addressing is really quite simple.  Each decoder box has a magic number
> built into it (like a serial number).  The cable company transmits on
> each channel (I presume in the blanking, but I don't know) the numbers
> of those boxes which are authorized to decode that channel.  This
> transmission is continuous.  It takes a noticeable (a second or so)
> amount of time to cycle through all of the numbers, so there is a
> variable delay from the time you tune in to a channel until the time
> your decoder receives the OK to descramble it for you.
> -- 
> Doug Pardee -- Terak Corp. -- !{hao,ihnp4,decvax}!noao!terak!doug

Actually, the boxes are not addressed that often. The box retains its state
until it loses power. After the power comes back on you have to wait for
your box to be re-addressed before it will again receive the pay channels
you've signed up for.  The data channel is on its own frequency, often
in the FM broadcast band. If you listen on an FM receiver often you can
hear this addressing signal which sounds like a high pitched buzzing sound.

Phil