Re: Using "Free" telephone power

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Article #21272

#21272

From: David Robins
Date: Mon, 01 May 1989 17:29

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In article <636@serene.UUCP> gbell@pnet12.cts.com (Greg Bell) writes:
>
>I'm still amazed at how phones run entirely off the phone line power.  They
>have lit dials, and audio amplifiers... and I had trouble lighting an LED!
>(trouble means the phone company equipment gets loaded down enough that it
>shuts off your line for a while!).  

I don't know how it is now, but the old Princess and other Bell System
phones had dials with incandescent bulbs, whcih were powered off AC by
a small wall transformer.  The power was carried throughout the house
phone wiring on the yellow/black pair (red/green reserved for signal).

However, my phone dialer IS powered by the phone line, but no light.

-- 
David Robins, M.D.  (ophthalmologist / electronics engineer)
The Smith-Kettlewell Institute of Visual Science,  ***  net:  uunet!skivs!dr
2232 Webster St, San Francisco CA 94115            ***  415/561-1705 (voice) 
The opinions expressed herein do not reflect the opinion of the Institute!

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!skivs!dr
From: dr@skivs.UUCP (David Robins)
Newsgroups: sci.electronics
Subject: Re: Using "Free" telephone power
Message-ID: <2829@skivs.UUCP>
Date: 1 May 89 17:29:50 GMT
References: <636@serene.UUCP>
Reply-To: dr@skivs.UUCP (David Robins)
Organization: Smith-Kettlewell Eye Research Institute, San Francisco, CA
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