Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: John Cowan Newsgroups: comp.dcom.telecom Subject: Re: Ringing a Busy Phone Message-ID: <6114@accuvax.nwu.edu> Date: 2 Apr 90 15:36:43 GMT Sender: news@accuvax.nwu.edu Reply-To: John Cowan Organization: ESCC, New York City Lines: 23 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 235, Message 10 of 11 In article <5863@accuvax.nwu.edu> stanley@stanley.UUCP (John Stanley) writes: > You didn't ask, but I will. "How does the CO know on a party line >which party is making a call?" Well, you all had untimed service and >the operator asked you on long distance calls. Newer systems put a >load from tip or ring to ground to indicate which party you are. This >was well beyond the old step-by-step we had, so "your number please" >on all LD calls. I have four-party service from Taconic Telephone at my summer house. (Until the recent arrival of a new family on the road, we had seven-party service, the maximum allowed by NY State.) I believe the "tuned ringing" method is used here, as we have been warned that answering machines are forbidden -- they will pick up on calls to our neighbors. The filtering isn't perfect, though; when my neighbor gets a call, my phone rings very softly. Long distance calls are handled by dialing 1+7+number, where 7 is a digit printed on the phone's number plate and labeled "DDD Code". I assume this code is different for all parties on the line, and signals the CO who is calling. Seems it would be awfully easy to cheat, but of course I don't. (no :-)).