Article View: sci.electronics
Article #16964Re: Telephone "in use" light
From: Dana Merrill
Date: Mon, 11 Jan 1993 15:04
Date: Mon, 11 Jan 1993 15:04
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In article <1993Jan10.063830.1164@athena.mit.edu>, cthomas@athena.mit.edu (Michael T Ford) wrote: > > In article <1io3i5INNnat@MINERVA.CIS.YALE.EDU> shaffer-wendy@MINERVA.CIS.YALE.EDU (Wendy Shaffer) writes: > >Regarding the telephone in use light, the Feb issue of Popular Electronics has > >a schematic. Unfortunately, I'm completely unfamiliar with how the telephone lines > >work. > >The schematic shows two wires going to the telephone line. One of them is marked with the word "Tip" and a + sign. The other is marked with "Ring" and > >a minus sign. Could somebody fill me in on what these mean and how to identify > >one from the other. Thanks > > Telephones nowadays run off of only two conductors. The red and green > wires are the most common. And if I remember correctly, red is tip, and > green is ring. (Someone correct me if this is backwards.) > Don't worry about hooking the circuit up backwards; the worst that will > happen, if anything, is that it won't work. > > Good luck, > Mike WZ0C Installers often pay little attention to polarity when installing residential wiring. You may find tip or ring on any color wire in the outlet. Many installations (particularly newer ones) use more pairs anyway which do not necessarily include red and green! I haven't seen the circuit mentioned, but a good design would include a polarity guard (all electronic telephones do) so that the connection polarity doesn't matter. dam ================================================================== Dana Merrill Bell Northern Research DMerrill@BNR.CA Research Triangle Park, NC ==================================================================
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Newsgroups: sci.electronics Path: arc1-ca.pugleaf.net!sparky!uunet!pipex!bnr.co.uk!bnrgate!corpgate!brtph560!NewsWatcher From: Dmerrill@bnr.ca (Dana Merrill) Subject: Re: Telephone "in use" light Message-ID: <Dmerrill-110193094958@47.140.3.192> Followup-To: sci.electronics Sender: news@brtph560.bnr.ca (Usenet News) Organization: BNR References: <8fHQtP600WAvM1Wc4j@andrew.cmu.edu> <1io3i5INNnat@MINERVA.CIS.YALE.EDU> <1993Jan10.063830.1164@athena.mit.edu> Date: Mon, 11 Jan 1993 15:04:21 GMT Lines: 36