dialtone and Tunelab

[Richard Moody]

----- Original Message -----
From: John Lillico, RPT <staytuned@idirect.com>
To: <pianotech@ptg.org>
Sent: Saturday, October 28, 2000 9:04 PM
Subject: Re: SOT


> >Pick up your phone and let the SOT listen to the dial tone.  In my area,
and
> >presumably elsewhere, the dial tone is a square wave audio 440 cps tone.
The
> >lights should stop dead on.
> >
> >Bill Simon
> >Phoenix
>
> Can anyone confirm what Bill says here. I've always known the (upper) dial
tone to be real close to A440 but figured it was about eight cents sharp!
>
> Bill, if you're right, I've got an Accu-fork for sale, batteries included.
>
> John Lillico, RPT,
> Oakville, Ontario
> (on the Bell Canada system)

Its a simple thing to do.  Open Robert Scott's Tunelab.  Put a mic to
the ear piece of the phone, or have Tunelab play A440 and listen to the
beats. ie listen to the dialtone and Tunelab at the same time.   Click on
the loudspeaker icon (or s) press-- A  and  4.   Now do a control (crtl) O
and enter  -4  so Tunelab is playing A440 4 cents flat.  Listen to the
beats.  You may have to wait 3 to 5 seconds to hear the first beat but there
they are, very sloooow but
distinct.  amazing!  So on my phone Ma Bell's dialtone is very close to 4
cents
flat.  Mic'ing shows A running flat, and a faint F pretty much on.  The dial
tone always sounded gargley to me, that must be the beats between A and
F---ric