Path: utzoo!telecom-request Date: Mon, 27 May 1991 17:29:39 GMT From: Jon Sreekanth Newsgroups: comp.dcom.telecom Subject: Re: Ringing Tones Around the World Message-ID: Organization: TELECOM Digest Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 402, Message 9 of 9 Lines: 36 In article YSAR1111@vm1.yorku.ca (Rick Broadhead) writes: > Are there any telephones on the market for a residential line that > produce a double ring? Or is such a feature restricted to PBX system > phones? > [Moderator's Note: I don't know if you meant it the way it came out, > but the telephone instrument has *nothing* to do with the ring you > hear as the caller. What you heard must have been some kind of fluke; > ome temporary switch problem. PAT] You may have reached a fax switch, or some similar hack. These units pick up the line on hearing a ring signal, and send out a "phantom ringback", waiting to sense a fax or modem carrier tone. A lot of them generate a pretty yucky ringback (= single stage filtered square wave). Since the ring at the called end and the telephone company ringback sent back to the caller are un-synchronized, and these boxes pick up the line very fast, it's possible that the only "ringback" the caller hears comes from terminal equipment, not telco ringback. Though it's surprising that they should generate a non-standard ringback, instead of the standard US ringback. At least one fax switch I know of (CCI, Colorado ?) has an EPROM upgrade to generate different countries' ringbacks. But to get back to the main thread: is it "mandatory" for all US exchanges to generate the familiar ringback ? Jon Sreekanth Assabet Valley Microsystems Fax and PC products 346 Lincoln St #722, Marlboro, MA 01752 508-562-0722 jon_sree@world.std.com