Path: utzoo!utgpu!watmath!clyde!bellcore!rutgers!netsys!vector!nobody From: embick@tetra.nosc.mil (Edward M. Embick) Newsgroups: comp.dcom.telecom Subject: Re: In-use light Message-ID: Date: 28 Oct 88 16:40:08 GMT Sender: chip@vector.UUCP Lines: 22 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 166, message 3 {{{ Ooooops. Although credited to me, the message this is in response }}} {{{ to was written by Larry Lang . This message appeared }}} {{{ during the mailing list outage, and at that stage my software was }}} {{{ munging "From" lines. Appologies to Larry and all. -chip }}} In article <614@vector.UUCP> chip@vector.UUCP (Chip Rosenthal) writes: >I built something like this once. It consisted of an outboard box, >essentially a continuity tester, with a power supply and LED. >The LED would light up whenever an extension >(besides my own) was lifted. The way it worked is simple: >Phone cable has four wires, two active (red and green) >and two inactive (yellow and black). ^^^^^^^^^^^^^^^^^^^^^^^^^^^ The second pair of wires are normally used for a second phone line, such as sysops have installed for their BBS's. This solution is NOT one that would maintain the integrety of you phone system! ------------------------------------------------------------------------------ Ed Embick (If God wanted me to write legibly, He wouldn't have invented email) Computer Sciences Corporation ____ ____ ____ 4045 Hancock St. MILNET: embick@tetra.nosc.mil // // // San Diego, CA 92110 \\___ ___// \\___ (619) 225-8401 x287