source file: m1381.txt
Date: Fri, 10 Apr 1998 10:02:29 -0700

Subject: Re: Telephone Touch Tones

From: "Fred Kohler" <Fred_Kohler@bc.sympatico.ca>

In TUNING digest 1379
monz@juno.com (Joseph L Monzo) said,
"The tones which sound when you press
numbers on the keypad of a touch-tone
phone are in ratios.  I had figured them
out once, because their arrangement into
dyads  follows a geometrical pattern
across the keys, but they were never
written down."


Those tones you hear are calle DTMF.
The web page
http://www.whatis.com/
has information on this and many other mysterious acronyms.

>From T.H. Tsim at
http://www.paranoia.com/~filipg/HTML/LINK/F_DTMF.html
we get:

"The tone frequencies were designed to avoid harmonics and other problems
that could arise when two tones are sent and received. Accurate transmission
from the phone and accurate decoding on the telephone company end are
important. They may sound rather musical when dialed (and representations of
many popular tunes are possible), but they are not intended to be so. "

Note that the tones were specifically designed to avoid harmonics.

I'm sure some enterprising microtonalist could find a musical use for them.
Heh, heh.

---Fred.

--------------------------------------------------------
 Fred Kohler, #7-240 Burnside Rd E, Victoria, BC, Canada
 phone:(250)388-7918  email:Fred_Kohler@bc.sympatico.ca
---------------------------------------------------------