Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!rutgers!texbell!vector!telecom-gateway From: tad@ssc.UUCP (Tad Cook) Newsgroups: comp.dcom.telecom Subject: Re: Cordless Phone Message-ID: Date: 29 Oct 89 19:29:38 GMT Sender: news@vector.Dallas.TX.US Organization: very little 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 479, message 6 of 10 In his posting, Cyril Bauer talks about a system using carrier current transmission on the power line for telephone extensions. Although this can work, there are a couple of problems with this. One is with all of the powerline noise filters and spike blockers that we have on our computers and electronic gear now. The ones with just an MOV are not a problem, but the better quality ones with filtering act as a big bucket for all the RF. Another problem is that power wiring at a premise is divided between the two legs of the 220 VAC line. A signal transmitted on one leg wont go to the other very well. One way around this is to hook a cap between the two 220 VAC legs at the service entrance to couple the signal between the two legs. One mod that may work with the noise filters is to put series inductors between the noise filter and the line. This would present high impedance to the RF. Many noise filters already have inductors, but if there is a capacitor on the line side, there would still be a problem without external inductors. Tad Cook tad@ssc.UUCP