Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!rutgers!ames!ptsfa!ihnp4!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: comp.dcom.modems Subject: Re: Telephone line quality Message-ID: <1731@kitty.UUCP> Date: Tue, 28-Apr-87 16:23:34 EDT Article-I.D.: kitty.1731 Posted: Tue Apr 28 16:23:34 1987 Date-Received: Thu, 30-Apr-87 04:09:56 EDT References: <27354@rochester.ARPA> Organization: Recognition Research Corp., Clarence, NY Lines: 76 Summary: Problem could be in digital central office switch In article <27354@rochester.ARPA>, ciaraldi@rochester.ARPA (Mike Ciaraldi) writes: > >> if this is so, then is there any point in getting a higher grade line > >> for one's home, when one has no control over the line quality for the other > >> 2/3 of the connection ?!? > > > > I'll answer (2) first, because it is the easier answer. In general, > >the quality of an interoffice trunk (i.e., a line connecting two telephone > >company central offices) is FAR superior to the quality of any subscriber > >line. > > This is from a long and very informative article, showing much more > familiarity with the characteristics of phone systems than I have. Thank you! > Nevertheless, I have a comment, based on my personal experience. > > My house, and the University of Rochester, are both served by > Rochester Telephone, at one time the largest independent telephone > company in the world (i.e. not part of AT&T or a government). > I live about 10 miles from the University, but both sites are well within > the local free calling area. > > For many years I have been able to communicate at 1200 bps > with almost no noise, using even rather inexpensive modems, > between my house and most parts of Rochester and the surrounding > suburbs. I can call bulletin boards, Rochester Institute of > Technology, and individuals with no problem. > But when I call the U of R, or someone in that neighborhood calls > a BBS near me, the error rate goes way up. Sometimes you can't even > hold the carrier. I have a regular residential line, but the > University and the BBS's have conditioned lines. > > I finally found someone at Rochester Telephone who knew what I > was talking about, and explained it to him. He said that the > two central offices involved happened to be connected by some of > the oldest trunk lines in the city, over 30 years old. > Until they were replaced, which would not be for several years, > the only thing I could try would be calling again and hoping > for a different (better) trunk. Sorry about the long quote, but I felt it necessary in order for my reply to be meaningful... I have had the "pleasure" [read "misfortune" :-( ] of dealing with Rochester Telephone in the past. Most of the problems I have encountered in the past dealt with their outlying central offices, such as Avon. These outlying CO's were mostly Stromberg-Carlson XY electromechanical switches, and were real trash for dial-up data transmission. The interoffice trunks feeding these outlying CO's also left something to be desired. However, within the population center of Rochester, the CO's have been mostly Western Electric #5 Crossbar, #1 ESS, and now #5 ESS. It is my understanding that Rochester Telephone is the largest non-Bell System customer of Western Electric (now AT&T Network Systems). I believe that Rochester Telephone also has Northern Telcom DMS-100 electronic switches, but I am not certain. It is my understanding that the central office quality and the interoffice trunk quality within the population center of Rochester has been rather decent. I presume this area to encompass your example area. While I am not in a very good position to dispute a Rochester Telephone engineer, I nevertheless feel your problem is NOT interoffice trunks. I am more inclined to believe that you are being victimized by faulty or maladjusted T-carrier and/or a digital central office which is not handling data very well. A T-carrier problem IS an interoffice trunk problem, but not in the same vein as my original article or the statement of the Rochester Telephone engineer. I don't want to get off on a tangent in this article, but suffice it to say that problems in sampling clock synchronization in digital switching offices can wreck incredible havoc with data. It is my understanding that some DMS-100 offices have exhibited this problem more severely that the AT&T digital offices. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"