Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!bellcore!texbell!vector!telecom-gateway From: goldstein%delni.DEC@decwrl.dec.com (Fred R. Goldstein dtn226-7388) Newsgroups: comp.dcom.telecom Subject: Re: Number of devices on 1 line? Message-ID: Date: 12 Jun 89 12:45:00 GMT Sender: news@vector.Dallas.TX.US Lines: 24 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 196, message 5 of 6 If I recall my Part 68 correctly, the rule on Ringer Equivalence Numbers is that all devices must not have a combined REN greater than 5. Not 6 or 8 as previously reported. This is the standard that all CO switches are built to. Some may actually support more, but the telco is obligated normally to allow up to 5 REN total, and that's what they're now built for. REN of 1 comes from the traditional electromechanical ringer, but not even all of them are equal to 1. I have a Northern Telecom deskset (1986 Link model) with a real bell (not a fire alarm chirper) with an REN of 0.8A, which is typical of modern equipment. Some modems and answering machines, which don't need to really ring, have RENs in the 0.1 range. A friend had trouble in her apartment, with phones not being audible, and it turned out to be an REN violation. The answering machine was something like 1.2, and there were four other phones... Unplugging any one device made them all ring, but with the REN overload, the ring voltage fell too low for them all to ring. SOme devices rang, but were anemic, while others didn't ring at all. Yes, it's a violation of telco rules to overload your line. If you really need to have more bells, you should get an external bell relay. fred