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From: alab@ur-tut.UUCP (Daniel F. Luna)
Newsgroups: sci.electronics
Subject: Re: Communication over power lines - is it legal?
Message-ID: <1286@ur-tut.UUCP>
Date: Fri, 8-May-87 04:18:05 EDT
Article-I.D.: ur-tut.1286
Posted: Fri May  8 04:18:05 1987
Date-Received: Sat, 9-May-87 18:47:05 EDT
References: <3271@ece-csc.UUCP>
Reply-To: alab@tut.cc.rochester.edu.UUCP (Daniel F. Luna)
Organization: Univ. of Rochester Computing Center
Lines: 25

>My question is this:  Does the power company get upset if you
>introduce a low-level (~1 volt peak-to-peak) high freq. (> 10 kHz)
>onto their lines (interior to your home).

   It is done all the time at AM frequencies (550kHz to 1600kHz) in the form
 of carrier current radio stations.  

 In addition, the power company itself uses this medium on the high voltage
system to transmit information between substations.

 The "BSR" system uses this method, as well.  So as far as I know, it is
OKEY DOKEY.

The limiting factor is whether it will interfere.  FCC rules say that if it interferes, you have to correct the interference, otherwise, it's ok.  In the AM 
carrier current realm, there is a formula which determines signal strength at
a specific distance.  Distance is proportional to inverse frequency, so likely
the audio range is quite ok.  

Industrial signalling equipment does this within complexes, and is also ok.

-- 
Daniel F. Luna 
PC-Person.
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