Path: utzoo!attcan!uunet!snorkelwacker!tut.cis.ohio-state.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request
From: drivax!marking@uunet.uu.net (M.Marking)
Newsgroups: comp.dcom.telecom
Subject: Re: Touchtone History
Message-ID: <10035@accuvax.nwu.edu>
Date: 23 Jul 90 19:29:43 GMT
Sender: news@accuvax.nwu.edu
Reply-To: drivax!marking@uunet.uu.net
Organization: Digital Research (Japan) Inc.
Lines: 32
Approved: Telecom@eecs.nwu.edu
X-Submissions-To: telecom@eecs.nwu.edu
X-Administrivia-To: telecom-request@eecs.nwu.edu
X-Telecom-Digest: Volume 10, Issue 507, Message 11 of 11


ssc!tad@beaver.cs.washington.edu (Tad Cook) writes:

) In article <9706@accuvax.nwu.edu>, drivax!marking@uunet.uu.net
) (M.Marking) writes:

) > *Dual* Tone Multi Frequency.) The frequencies are:
) > 
) > 			1209	1336	1477	1653 Hz
)                                                 ^^^^WRONG!

) Actually, the fourth column tone is 1633 Hz.

You seem to be right.

My reference was page 88 of "Telecommunications Switching" by J.
Gordon Pearce, Plenum Press, 1981.

It seems I reached for the wrong reference first. 1633 Hz is the
choice of:

	den Heijer and Tolsma, Data Communications, Glentop, 1986

	Martin, Introduction to Teleprocessing, Prentice-Hall, 1972

	Signetics, TEA1046 data sheet, 1985

Unfortunately, I don't have a copy of the Standard.

So 1633 Hz wins over 1653 Hz by 3 to 1.

I offer my apologies.