Path: utzoo!attcan!uunet!seismo!sundc!pitstop!texsun!convex!killer!vector!nobody From: amdcad!snap.AMD.COM!hayes@ames.arc.nasa.gov (Jim Hayes) Newsgroups: comp.dcom.telecom Subject: Re: DTMF vs. Touch-Tone (and some good reading) Message-ID: Date: 25 Dec 88 04:55:03 GMT Sender: chip@vector.UUCP Lines: 29 Approved: telecom-request@vector.uucp X-Submissions-To: telecom@bu-cs.bu.edu X-Administrivia-To: telecom-request@vector.uucp X-TELECOM-Digest: volume 8, issue 209, message 3 prindle@NADC.ARPA (Frank Prindle) writes in article : >X-TELECOM-Digest: volume 8, issue 206, message 6 > >I'm curious when the term DTMF (Dual Tone Multi Frequency) became synonymous >with Touch Tone. As I recall, DTMF once designated the set of dual-tone >frequencies used for in-band signaling on long distance trunks, which used >a completely different set of tones than Touch Tone, and was always generated >within the CO, not by any phone set (well, except for the "blue boxes"). The in-band signaling is called MTMF. (Multiple Tone-Multiple Frequency), TouchTone has always been called DTMF. MTMF is on its way out, but is certainly not gone yet and I doubt it will fade completely anytime soon. There is some great reading in _The Bell System Technical Journal_ (which has had several name changes over the years.) I recently visited the New York Public Library (the biggy in the middle of the city) and got a complete tutorial on the evolution of ESS, cellular phones, signaling, call routing and TSPS. Free, written by the designers. Just find a empty microfilm machine and plan to spend about 8 hours reading. -Jim Hayes Advanced Micro Devices, Inc., Sunnyvale CA. hayes@amdcad.amd.com /earth: file system full {ucbvax|sun|decwrl}!amdcad!hayes These are not opinions of AMD.