Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!sunybcs!ubvmsd.cc.buffalo.edu!v118hj3d
From: v118hj3d@ubvmsd.cc.buffalo.edu (Anthony M Petro)
Newsgroups: sci.electronics
Subject: Re: DTMF tones
Summary: Un-documented tones?
Message-ID: <31477@eerie.acsu.Buffalo.EDU>
Date: 25 Jul 90 18:41:47 GMT
References: <44900010@uxa.cso.uiuc.edu> <44900011@uxa.cso.uiuc.edu> <1202@gold.GVG.TEK.COM> <1990Jul25.125339.1665@focsys.uucp>
Sender: news@acsu.Buffalo.EDU
Reply-To: v118hj3d@ubvmsd.cc.buffalo.edu
Distribution: usa
Organization: University at Buffalo
Lines: 22
Nntp-Posting-Host: ubvmsd.cc.buffalo.edu
News-Software: VAX/VMS VNEWS 1.3-4.1

> 
>  I also came across some undocumented but supposedly valid tones.
>Anyone have an idea or care to guess what they do?
>Fo = 697Hz & 1633Hz
>F  = 770Hz & 1633Hz
>I  = 852Hz & 1633Hz
>P  = 941Hz & 1633Hz
> 
>watmath!focsys!brad

this is a wild guess from somewhere in the recesses of my memory, but...

those tones were logical completions of the 4x4 matrix of frequencies, and
while not found on most telephones were sometimes used by the military
for purposes i can't recall...

as i said, my recollection is quite fuzzy; can anyone elaborate?

anthony m. petro   "beethoven"    i can say what i want; i'm just an undergrad
V118HJ3D@UBVMSD.BITNET            "soon the gypsy queen in a glaze of Vaseline
petro@sun.acsu.buffalo.edu         will perform on guillotine; what a scene,
..!uunet!acsu.buffalo.edu!petro   what a scene..."