Message-ID: <004701c16859$556ab880$0a00a8c0@ThreeLakes.ca>
From: "Larry Kayser" <kayser@sympatico.ca>
To: rsgb_lf_group@blacksheep.org
References: <7D653C9C42F5D411A27C00508BF8803D55C618@PDW-MAIL-R1>
Subject: Re: LF: Re: Ringing Voltage on Telephone	, boo-boo
Date: Thu, 8 Nov 2001 08:28:39 -0500
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Gentlemen:


> Same in the UK
and
> > I don't know how it is in Canada, but in the States, the 20Hz
> > component is
> > the only ringing voltage sent across the line to the
> > telephone set,

both these are wrong.  Go and get a scope and have a look.  The proper
designation of ringing induction from CO to Callee (a telephone term
differentiating Caller [the originator of a call] from the person receiving
the call) is "20/1000"  which is composed of a 20 cycle sine wave modulating
a 1000 Hz tone.

Remember as well the ringing induction can be from Tip to Ring (normal in
North America), from Tip to Ground, from Ring to Ground, - I do remember
that the standard in the UK is different than here.

I did not speak to the pseudo ringing tone provided to the Caller.

A quick reality check, think through the reactance of a DC blocking
capacitor at 20 Hz and 1000 Hz, when you rectify the AC through the
capacitor and power a small relay from the result you are not working with
much of the 20 Hz component.

Larry
VA3LK