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From: kgdykes@watmath.waterloo.edu (Ken Dykes)
Newsgroups: comp.dcom.telecom
Subject: Re: Help Wanted: Telco Service has Mid and High Frequency Loss
Message-ID: <15983@accuvax.nwu.edu>
Date: 10 Jan 91 10:57:36 GMT
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X-Telecom-Digest: Volume 11, Issue 26, Message 1 of 8


In article <15903@accuvax.nwu.edu> casey@gauss.llnl.gov (Casey Leedom)
writes:

>  The other possible source of these problems is the house wiring.
>The wiring in the house is very old, untwisted aluminum three-pair.
>Yes, I said aluminum!  Don't ask me -- everyone I've told of and

   I wouldn't worry so much about Aluminum, but UNtwisted? eeeeeek!

>  There's about forty feet of the wire strung between the drop box and
>the telephone jack I'm trying to use.  It's also wired serially
>through a jack about ten feet from the drop box.  That earlier jack
>has a telephone set on line one, but nothing on line two.  The far

   Does your wiring-run pass any furnace/air-cond/water heater/etc
which may have a relay/starter going about every 45 minutes? perhaps
when it "starts" you get some sort of induction pickup on your wires.

Also, do your mid->high frequency response problems occur at harmonics
of 60hz (ie: your phone wires pass hydro wires, the 60hz induction
provides a possible dampening effect?)

[caveat: I really dont know what I'm talking about.]

>  While in PEP mode, I can hear a very small amount of cross talk when
>both the modem and voice lines are idling (very low level regular

   Cross-talk will disappear with twisted pair (or at least "very
small" levels will :-)

>    2.	I welcome any comments about the potential problems that very
>	old, untwisted aluminum wiring might generate and in particular,
>	does anyone think it could be responsible for my frequency
>	response loss?

   I think UNtwisted is unwise at best of times, heck, bite the bullet
install lots of twisted pairs and run Ethernet all over your house :-)

>    3.	I think I remember hearing, perhaps in this group, that twisted
>	pair wiring can actually *degrade* frequency response because of

   You got it backward in my belief.

>    4.	We're thinking of running twisted copper six-pair throughout the
>	house to accommodate future expansion with an Ethernet, AppleTalk
>	net, and up to three phone lines.  Does anyone see any problem

   Yes, yes, capacity planning! wire is cheap, the "running it" is a
pain, do it once, but run a lot of pairs.


Ken Dykes, Software Development Group, UofWaterloo, Canada [43.47N 80.52W]
    kgdykes@watmath.waterloo.edu  [129.97.128.1]        watmath!kgdykes
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