Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!charon!hydra.unm.edu!ee5391aa
From: ee5391aa@hydra.unm.edu (Duke McMullan n5gax)
Newsgroups: sci.electronics
Subject: Ringing telephones with line voltage
Summary: It works for me....
Keywords: bandpass filters: are they there?
Message-ID: <5012@charon.unm.edu>
Date: 3 May 89 14:35:46 GMT
References: <636@serene.UUCP> <920@snjsn1.SJ.ATE.SLB.COM> <3139@kitty.UUCP>
Sender: root@charon.unm.edu
Reply-To: ee5391aa@hydra.unm.edu.UUCP (Duke McMullan n5gax)
Organization: University of New Mexico, Albuquerque, NM
Lines: 29

In article <3139@kitty.UUCP> larry@kitty.UUCP (Larry Lippman) writes:
>	Sorry, but you canNOT ring a phone with "house current".  Virtually
>all conventional telephone ringers are frequency selective, and operate only
>between 16 and 32 Hz; 60 Hz won't cut it.  Some ringers used on older
>party line systems (like the "harmonic", "decimonic" and "synchronic") were
>_very_ freqeuncy selective, with a "bandpass" of 5 Hz or less.

Wellll -- I do it on occasion. I generally pull the voltage down to about
90 VAC with a variable autotransformer for safety, but the 'phone rings loudly
and continuously.

If you close the hookswitch, you get a loud buzz. ;^)

I've never tried it on one of the new solid state (easily damaged, cheap,
poorly made, etc., etc.) 'phones so widely available, but ALL of the old-style
Western Electric sets I've tested (just under a dozen, I'd imagine) ring
just fine at 60 Hz. The ring does seem a little "buzzy" or rapid, as you'd
expect.

I don't speak for every 'phone, but you can ring _some_ of 'em with 120VAC.


					Call me a 'phoney,
						    d



     "To be or not to be -- that is the square root of 4 B^2." -- Anon.
   Duke McMullan n5gax nss13429r phon505-255-4642 ee5391aa@hydra.unm.edu