From: Floyd Davidson <floyd@ims.alaska.edu>
Subject: Re: How do You Hook up a Phone For a Play?
Organization: University of Alaska, Institute of Marine Science
Date: Wed, 20 Feb 1991 05:49:04 GMT

Roy Smith writes:

>John_Richard_Bruni@cup.portal.com writes:

>> I have on several occassions seen phones hooked up to AC to ring the
>> bell for plays 

>Our Moderator replies:

>> What you are suggesting is a *highly dangerous* practice ...

>	OK, I'll agree that it's a Bad Idea, and I'm not advocating
>that you do it, but let's think about this for a minute.  Just how

>[Moderator's Note: An actual phone line not being used has closer to
>forty volts DC on the line doesn't it? It goes up to ninety volts only
>when ringing ... and only around ten volts DC when off hook ... I
>think my figures are correct. But a straight 110-120 volts AC coming
>into it for even a few seconds?  Never! 

That is not really such a bad idea, *if* you do it right.  *If* you
do it wrong it is a *really* bad idea.

Normal ringing voltage is about 100 volts at 20 Hz, and it is truely
nasty stuff.  Getting jerked around by 20 Hz current will teach some
true respect.  Don't confuse that with a relatively mild 60 Hz shock.
(Either one can kill you.)

But, the ring voltage is current limited.  It is in series with a
ballast lamp.  Even a dead short will not blow a fuse.  In an earlier
post someone suggested a fuse and a 5k resister in series with the
phone.  It probably won't ring the phone.

Rig up a lamp socket in series with the phone and a push button
switch.  Plug in a relatively small lamp, say a 15 watt job.  If the
phone rings loud enough, that's it, if not then use a larger lamp
until it does.

One word of caution: Have someone who understands electicity do this.
The switch MUST be on the hot side of the wiring.

If this is wired correctly there is no more danger from using 60 Hz
current than from 20 Hz.  Either way you end up with enough juice to
knock your socks off if you touch it.  And I'll admit to being semi
scared to death of 60 Hz house current, but I'm also ten times as
scared of 20 Hz ring current.  It *HURTS*!


Floyd L. Davidson  |  floyd@ims.alaska.edu   |  Alascom, Inc. pays me
Salcha, AK 99714   |    Univ. of Alaska      |  but not for opinions.

From: Floyd Davidson <floyd@ims.alaska.edu>
Subject: Re: How do You Hook up a Phone For a Play?
Organization: University of Alaska, Institute of Marine Science
Date: Thu, 21 Feb 1991 08:39:38 GMT

In reference to using 117 VAC 60 Hz to ring a phone:

In article <telecom11.139.11@eecs.nwu.edu> gabe@sirius.ctr.columbia.
edu (Gabe Wiener) writes:

> The danger isn't necessarily frying the phone (though I'm quite sure
> that with the low level of quality of today's telephones, most of them
> would fry) as much as it is frying the ACTOR who picks up the phone
> while wall current is flowing through it.

I posted my view on this subject earlier.  Since Pat seems to have
missed the essense of what I said, and this article more or less falls
in line with Pat's feelings that it is intrinsically and specifically
hazardous...

One more time: 100 VAC 20 Hz is JUST as dangerous, if not more so,
that 117 VAC 60 Hz.  Using house current to ring the phone is no more,
and no less, dangerous, than ANY other reasonable way you can make the
ringer work.

In fact 60 Hz current may be less dangerous than 20 Hz.  60 Hz current
can cause all the normal damage everyone is familiar with if you get a
shock, but 20 Hz does something that perhaps most people are not aware
of: Your muscles can and will go into clonic-tonic jerks at the 20 Hz
rate.  They cannot respond that way to 60 Hz current as it is too
fast.  Hence, in one way, it might be said that 20 Hz current is MORE
of a problem than 60 Hz.  20 Hz current will certainly hurt more and
usually will be harder to get loose from, than 60 Hz.

The difference between having 90-100 VAC and 105-120 VAC (ringing
voltage vs. house current voltage) is insignificant.

Hence what I am saying is that using 60 Hz is a viable way to ring the
phone, just as 20 Hz is, IF WHOEVER HOOKS IT UP KNOWS WHAT THEY ARE
DOING.  If they don't it is just as hazardous either way.

If the phone is well enough insulated for the normal ring voltage, it
is well enough insulated for house current.  And it certainly is.


Floyd L. Davidson  |  floyd@ims.alaska.edu   |  Alascom, Inc. pays me
Salcha, AK 99714   |    Univ. of Alaska      |  but not for opinions.