Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!usc!apple!netcom!stratus!cloud9!jjmhome!m2c!wpi!reynhout
From: reynhout@wpi.wpi.edu (D Andrew Reynhout)
Newsgroups: sci.electronics
Subject: Re: power from phone line
Summary: Ring voltage...
Keywords: phone, power, remote
Message-ID: <6101@wpi.wpi.edu>
Date: 8 Dec 89 06:45:15 GMT
Reply-To: reynhout@wpi.wpi.edu (D Andrew Reynhout)
Organization: Worcester Polytechnic Institute, Worcester ,MA
Lines: 33

In article <5651@internal.Apple.COM> ems@Apple.COM (Mike Smith) writes:
>In article <6300@lindy.Stanford.EDU> sorka@ucscb.UCSC.EDU (Alan Waterman) writes:
>>
>>One thing you forgot to mention is that you get a lot more power out
>>of the line when it is ringing. I got the worst shock of my life when
>>I held the red and green wires(one in each hand) while the line sent
>>a ring signal. It almost knocked me out. It mush have been high voltage
>>and low amps because it went through me real easy.

>Vague memory from too many decades ago... I think the ring signal is
>pulsed DC at about 50 V and the current is 'all the inductor can carry'...

   Correct me if I'm wrong, but my memory from altogether too recently is that
the ring signal is a 90+VAC signal, at 17hz.  Current, I have no information
on.  The shock was never particularly bothersome to me, and I've been hit more
times than I can recall.  Of course, electric shock affects different people
differently.

   As an aside, a local paper once printed an article originally appearing in
the NYTimes, explaining how to wire your own extension telephones.  They didn't
bother to mention the ringing signal.  I wrote in, noting that the application
of such a jolt to a person wearing a pacemaker, for example, could be more than
irritating...possibly deadly.  I suggested taking one extension off-hook
(48VDC) before attempting anything.  There were a number of other glaring
errors in the article, like the completely incorrect explanation of the 
two-four wire possibilities.  They printed it, and forwarded it to the NYT, 
who is rumoured to have also printed it... my journalistic debut.. :-)

   Andrew
-- 
  Andrew Reynhout   (Internet: reynhout@wpi.wpi.edu)

  "Maybe if we pretend this never happened, they'll all just...go away."
                                           - Laurie Anderson