Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!ucbcad!ucbvax!decvax!decwrl!nac.dec.com!nourse From: nourse@nac.dec.com.UUCP Newsgroups: comp.dcom.modems Subject: Phone Line Quality Message-ID: <9728@decwrl.DEC.COM> Date: Wed, 6-May-87 16:26:22 EDT Article-I.D.: decwrl.9728 Posted: Wed May 6 16:26:22 1987 Date-Received: Fri, 8-May-87 03:54:21 EDT Sender: daemon@decwrl.DEC.COM Organization: Digital Equipment Corporation Lines: 57 > Path: decwrl!decvax!ucbvax!kitty.UUCP!larry > Subject: Telephone line quality > Posted: 19 Apr 87 05:35:00 GMT > ... the transmission loss on most interoffice trunks originating at End > Offices (Class 5) trunks is carefully kept below 4.0 dB... > Toll Center (Class 4) and up... below 2.6 dB > a reasonably flat transmission characteristic between 300 and 3,000 Hz. What are the specs for signal-to-noise ratio? If I want to call out of the three-small-town local calling area, I have to dial 1 which routes the call out to Leominster, 15 miles away. > ... Trunks which fail to pass these automatic tests are disabled > until repair is effected. That must be why I sometimes get a fast busy, or drop back to a dial tone, when i dial 1 (this is before I get to dial any other digits). I suppose it can thus disable ALL the trunks. That does, of course, also affect 0 (for Operator) and all paths to Repair Service. > So the point is: under virtually all circumstances, > you should have little concern about the transmission quality of interoffice > trunks, as compared to your own subscriber loop. Are old, rural, step-by-step exchanges an exception to this? The noise starts when I dial 1, so I don't think the subscriber loop has anything to do with it. > ...some of this standardization has gone to hell with the advent of > Alternate Long Distance carrier... Some local operating companies (including ours) are using that as an excuse to let line quality deteriorate, even for calls within the LATA. > This is NOT a "plug" for AT&T; it's just a simple fact of life since > AT&T still runs all the major toll switching centers in the U.S.) That may be why we still don't have `equal access'. (New England Telephone says there are `no plans' to implement it, or even touch-tone, in our town). To use an alternate carrier, we have to dial: 1 -950-0xxx [access code][number] When I've used Sprint from a place with decent equal-access, the line quality was better than AT&T. > the comparatively small additional monthly and installation charge is well > worth it to get a better subscriber loop. I just checked with New England Telephone. They said there is no such option. In 1980, when I had a Bell 212a modem installed (with an RJ41 jack), the installer fiddled around with his test gear on the phone line for a couple of hours, but I can detect no difference in quality from my other phone line. It is billed as a standard business phone line. What does the switch, and the collection of resistors and capacitors inside an RJ41 jack do?