Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!sri-unix!hplabs!ucbvax!ucsfcgl!pixar!aaa From: aaa@pixar.UUCP (Tony Apodaca) Newsgroups: net.sources Subject: Re: Re: Pending FCC ruling threat to modem users Message-ID: <403@pixar.UUCP> Date: Tue, 23-Dec-86 00:19:17 EST Article-I.D.: pixar.403 Posted: Tue Dec 23 00:19:17 1986 Date-Received: Tue, 23-Dec-86 19:04:04 EST References: <1572@brl-adm.ARPA> <3454@curly.ucla-cs.UCLA.EDU> Reply-To: aaa@pixar.UUCP (Tony Apodaca) Organization: Pixar -- Marin County, California Lines: 44 Keywords: modems, bandwidth, carrier, sex (no, not really) Summary: facts is facts In article <3454@curly.ucla-cs.UCLA.EDU> stiber@zeus (Michael D Stiber) writes: >In article <1572@brl-adm.ARPA> OCONNORDM@ge-crd.arpa (OCONNOR DENNIS MICHAEL) writes: >>First: MODEM calls DO NOT cost the phone company the same amount as >>other calls. They tend to be longer, and don't tolerate noise as well. > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > >1) You've obviously never had a sister (or daughter). Do families with >teenage girls pay more for phone service? Unlimited local calling >is just that _unlimited_. > >2) Modems use the same lines as voice. The assertion that they tolerate >noise less well is irrelevant, since they do not get special >priveledges. I'm sure that this discussion is going hot and heavy in net.dcom.etc but I'll answer here anyway. Flame off, Mike. The point is true even if the rationale is messed up. Modem calls DO cost the phone company more, for several reasons: 1) They are continuous. The dual carrier never stops. Therefore, the phone company must supply bandwidth to the call continuously even if there is no "valid" data. They cannot time-multiplex their signals. There are small breathing and thinking pauses in all voice conversation, and 99% of voice is half-duplex, even a teenage girl's conversations. 2) They are high bandwidth. The phone line was designed with human voices in mind, and they are pretty low bandwidth, as everyone knows. Also, everyone knows that their modems strive to get the most out of it, so they use it all up (if they didn't you'd buy a new one!). However, the phone company "counts on" the signals being voice-like, so they can cram as many signals into one wire as possible, and a modem transmission screws up their frequency-division multiplexing. 3) The carrier on some modems just happens to overlap a critical region of part of the phone company's equipment's frequency allocation. The circuits known as "echo suppression" use it to monitor themselves, and kick in higher bandwidth and better circuits if there is too much echo on the line. If they didn't have it, you'd bitterly complain about the quality of your long-distance connections. Voice doesn't have much of these freqs, but the carrier flips it out, causing it to allocate too much signal to your call. I don't work for the phone company and I dislike paying more for modem service just like the rest, but as a EE, I have to admit that "facts is facts". Didn't Wash U teach you anything? ;-) What is this doing on net.sources, anyway????