Path: utzoo!telecom-request Date: Sun, 19 May 91 23:14 PDT From: John Higdon Newsgroups: comp.dcom.telecom Subject: Re: Touch-Tone Selections From Overseas Reply-To: John Higdon Message-ID: Organization: Green Hills and Cows Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 381, Message 8 of 10 Lines: 30 Claus Tondering writes: > One of three things happens: > 1) It works perfectly, and I get connected as requested. > 2) It works only if I hold each key down for two or three seconds. > 3) Absolutely nothing happens. The American party does not recognize > my touch-tones. > Why this difference in behavior? What can I do to make it work always? > Where does the fault lie? In Europe? In the US? In the satellite? This could very well be the result of "twist", the reception of the component tones of a DTMF at unequal levels. While the DTMF frequencies fall squarely in the "voice" band of a telephone channel, sometimes the circuit will have a non-flat frequency response characteristic. This means that on a single digit, the high tone may be detected at a significantly different level than the low tone. Such a condition usually results in the non-registering of the digit. Holding the button down and extending the length of the tone will sometimes work because the receiver can occasionally adapt to the condition while the tone is sounding. Otherwise, you would probably have to hang up and get another circuit. John Higdon | P. O. Box 7648 | +1 408 723 1395 john@zygot.ati.com | San Jose, CA 95150 | M o o !