Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!netsys!vector!telecom-gateway From: johnl@esegue.segue.boston.ma.us (John R. Levine) Newsgroups: comp.dcom.telecom Subject: Re: Line Capture Device - RJ31X Message-ID: Date: 4 Oct 89 02:39:51 GMT Sender: news@vector.Dallas.TX.US Reply-To: johnl@esegue.segue.boston.ma.us Organization: Segue Software, Cambridge MA Lines: 23 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 431, message 7 of 9 An RJ-31 is a specially wired connector placed in series with the phone line near where it enters the house, in front of all the other phones. You plug an 8-position miniature phone plug into it. Four wires are used: pins 5 and 4 are tip and ring from the phone company, and pins 8 and 1 are tip and ring to the rest of the phones. The equipment you plug in, most often a burglar alarm, normally bridges 1 to 4 and 5 to 8, so the rest of the phones act normally. When it wants to make a call it can butt in, force a hangup, and do whatever it wants. There are little shorting bars in the RJ31 socket that bridge 1 to 4 and 5 to 8, so if you unplug the equipment the rest of your phones work. The best place for the RJ31 is inside the alarm control box where a burglar can't unplug it easily, but they usually seem to be installed near where the phone line enters the house. Regards, John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 492 3869 johnl@esegue.segue.boston.ma.us, {ima|lotus}!esegue!johnl, Levine@YALE.edu Massachusetts has 64 licensed drivers who are over 100 years old. -The Globe