> Frank's mention of 'relatively low-quality cable' is really the salient
> point. The telco cabling over several km is twisted pair(s) which resists
> interference, but house wiring (especially 'extension cords') tend to be
> flat/ribbon because it's easier to hide under carpet and easier for the
> diy-er to fit connectors. If you want to make any significant run in the
> house, try to get twisted pair.
Actually, that is THE issue. If your house wiring is appropriately
twisted, then there is absolutely no loss due to distance within the
house itself. A bigger issue are "taps" which provide all sorts of
nasty near-field reflections. Unfortunately, if you place the modem as
close to the NID (Network Interface Device, ie, entrance) and NOT
apply an ADSL filter to the rest of the house wiring (best solution is
called a NID-SPLITTER which places the filter inside the NID itself
and will make the Red-Green pair Voice and Yellow-Black Data), the
rest of the house wiring will look like near-end taps which kinda
messes things up if the general health of the ADSL connection is near
the edge of working.
Technically, there is no reason to worry about modem location within
the house if the house wiring is healthy. The reason why the telephone
company writes those guides that way (and I co-wrote the one for our
company with the same general instruction) is to get ourselves off the
hook (pun intended) for house-wiring issues. Inotherwords, there is no
technical reason, just a legal reason.
When I added ADSL to my previous house, I had to do a little
telephone-line surgery. There was a 5-pair that ran through the entire
house and daisy-chained all the outlets together. Just inside the
entrance I installed a punchblock (joys of being in the telephone
industry), and added a filter to just the first pair (typically
red-green). The second pair was kept bare to the outside entrance.
This way ALL outlets were filtered for the first line. My modem was
wired to attach to the second pair (typically yellow-black). As a
result, every outlet in the house was automatically filtered for voice
and unfiltered for the modem.
We now live in a condo where the wiring is, uh, a wee bit flaky. I
just use the standard line-lump filters for all telephone devices and
plug the modem in wherever it is convenient.
AG
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