Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!bcm!dimacs.rutgers.edu!rutgers!cbmvax!grr
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.dcom.modems
Subject: Re: Help: My telco has mid and high frequency loss
Message-ID: <17323@cbmvax.commodore.com>
Date: 10 Jan 91 00:32:24 GMT
References: <88953@lll-winken.LLNL.GOV>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 63

In article <88953@lll-winken.LLNL.GOV> casey@gauss.llnl.gov (Casey Leedom) writes:
> 
>   I just moved into a house in the Berkeley hills.  I plan on
> tele-commuting to work several days a week using an X terminal and V.32
> over Telebit T2500s (GE7.00 PROMs.)
...
>   The other possible source of these problems is the house wiring.  The
> wiring in the house is very old, untwisted aluminum 3-pair.  Yes, I said
> aluminum!  Don't ask me -- everyone I've told of and showed the wiring to
> says they've never heard of aluminum being used for telephone wiring ...
> and some of them have been in the telephone business for over twenty
> years!

I'd find it really wierd if it was aluminum and not tinned copper...
> 
>     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 wouldn't be too quick to blame the house wiring, the amount of wire there is
small compared to the local loop.  Usually house wiring problems are due to
loose or corroded conections, which cause a static noise, especially when the
weather is damp.  Make sure the wire and connectors are clean and screwed down
tight.  Check for obvious crip type splices where shorter pieces of wire were
joined or extensions added.

You can replace the wire if you want, but I wouldn't be too optimistic about
improvments.

>     3.	I think I remember hearing, perhaps in this group, that twisted
> 	pair wiring can actually *degrade* frequency response because of
> 	capacitance coupling.  Am I dreaming that up?  Will I be doing
> 	more harm than good by running copper twisted pair?

Not likely to be a significant effect either way.

> 
>     4.	We're thinking of running twisted copper 6-pair throughout the
> 	house to accommodate future expansion with an Ethernet, AppleTalk
> 	net, and up to three phone lines.  Does anyone see any problem
> 	with cross talk doing this?

Shouldn't be too much a problem, although you might hear some "digital" noise
in your phone due to pick up of "RF" signals from the network stuff.  If this
happens you can treat it the same way you would CB or Ham Radio pickup.

I'd suggest complaining to the telco in terms they can understand.  Tell them
that the volume is too low or there's ugly static anytime it rains.  They might
either install a booster amp or give you a different circuit.  This *might*
help.  On the other hand, you just might be so far from the central office that
this is all the quality you're going to get.  You might also consider getting
a "foreign exchange" phone line into that other central office if it's closer
or has new equipment, but there's a fair chance that you just end up with an
even longer link, still going to the old central office and thence to the other
exchange...plus they'll want to charge you a bunch of money for it.

Good luck...

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)