Path: utzoo!attcan!uunet!pyrdc!netsys!vector!chip From: chip@vector.UUCP (Chip Rosenthal) Newsgroups: comp.dcom.telecom Subject: Submission for comp.dcom.telecom Message-ID: Date: 2 Nov 88 05:03:42 GMT Organization: Dallas Semiconductor Lines: 52 Approved: telecom-request@vector.uucp X-Submissions-To: telecom@bu-cs.bu.edu (TELECOM Digest Coordinator) X-Administrivia-To: telecom-request@vector.uucp (USENET Telecom Moderator) X-TELECOM-Digest: volume 8, issue 169, message 5 In article wendyt@pyrps5.pyramid.com (Wendy Thrash) writes: > > I'm the formerly happy owner of a Panasonic answering machine similar to one > described in a recent article here. A week ago I moved to San Francisco. > My phone line is the third one in the apartment, and the wires were apparently > run by a friend of my roommates rather than by Pac Bell. My phone works OK > in the new apartment, but my answering machine will not work; it answers the > phone, jiggles its tapes a couple of times, and hangs up. > > I think the machine believes that another extension has been taken off hook, > and courteously relinquishes the line. This would be a feature if, in fact, > another extension had been taken off hook, but there is no other extension > on the line. > > My answering machine works fine on my roommates' lines. Their answering > machines work on my line. I doubt that improper wiring is the problem; otherwise you would be having other noticeable problems like hum or crosstalk. Based upon the manner in which you have swapped machines and lines, and your results, my guess is that YOUR line may be served through some type of subscriber line carrier or concentrator device. While "normal" telephones will work on subscriber line carrier devices, the tip and ring voltage is often MUCH less than that supplied through a "normal" line. In the case of analog FDM systems like the Continental AML variety, on-hook voltage is ONLY 6 VOLTS! The older WECO 1-type concentrator used 24 volts, rather than the usual 48. So, your telephone answering machine may not get sufficient off-hook loop current following ring-trip and answer, and therefore think that an extension has been picked up. Subscriber line carrier or concentrator devices are used to effect "pair gain" in rapidly growing areas where there are insufficient cable pairs to service the subscribers; i.e., the apparatus multiplexes through analog FDM or digital PCM additional subscriber lines on one physical pair. To find out for certain about the status of your telephone line, measure the on-hook voltage with a digital voltmeter. If it is less than 48 volts, then you have just confirmed the problem. Newer WECO subscriber line concentrator systems (like the SLC-96) present 48 volts, and should not cause a problem. It sounds like you are probably served by an older device of some sort. In general, you have no "right" by virtue of telephone company tariffs to insist that your telephone line be a "physical" pair rather than multiplexed. However, you can politely ask. If all else fails, you can always drive the telephone company repair service nuts by repeated calls complaining about line noise; multiplexed circuits are almost always noisier than physical circuits, and they may change your pair to a physical one just to shut you up. :-) <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {att|hplabs|mtune|utzoo|uunet}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"