Check in ...East Coast BLACKOUT

Montblack wrote:

Now I'm confused. Is my DSL running at higher frequencies, over the same
(single) wire strand that my voice is running on? Or is it running on the
second wire strand, in my standard household wire - which contains 2 wire
strands? Or is it using both strands?

It depends. Read on.

Newps replied:

It takes two wires to have a voice line. There are typically 4 wires in a
residential phone line; red, green, yellow and black. Normally the first
phone number uses the red and green wires. The other two will be for your
second phone number, should you get one. The DSL uses the same two wires as
your first phone number, with a filter to keep the two things separate.

Many houses with DSL are wired as Newps writes, but not all. DSL operates at
frequencies that are unused by "plain old telephone system" (POTS); like 20KHz
and up. Therefore the phone company can provide DSL without stringing new
copper from the central office to the home (which would be a *huge* cost),
provided the quality of the line is up to the task (this is the physics behind
the "X,000 ft rule", where "X" is 18 or 20 or so). Putting the DSL signal on
the voice pair usually requires a high frequency attentuator be placed at each
phone, however.

Some neighborhoods, like mine, are wired with optical fiber to the pedestal (in
the alley, shared by several homes), and then copper from the pedestal to the
outlet. Since I only have one landline (red-green), the telephone company
opted to use the second copper pair (yellow-black) as the DSL line. This saved
me the hassle of having the DSL filters (high freqency attenuators) at each
phone.

Russell Kent

("Newps" wrote)
It takes two wires to have a voice line. There are typically 4 wires in
a residential phone line; red, green, yellow and black. Normally the
first phone number uses the red and green wires. The other two will be
for your second phone number, should you get one. The DSL uses the same
two wires as your first phone number, with a filter to keep the two
things separate.

Looks like a clear explanation. Thanks.

--
Montblack

"Montblack" wrote:
My comment was home phone "wire" (singular) + DSL wire (singular) = 1
standard household phone wire pair. Maybe could have been more clear. I
meant "each" wire inside the pair. You (and Peter Gottlieb) read 2 separate
pair of wires - I think.

I'm not at all sure what to make of that. In phone-speak, nobody ever
talks about "wires" or "strands". You talk about "pairs". A 2-pair
cable will have in it 4 wires:

blue w/ white stripes
white w/ blue stripes
orange w/ white stripes
white w/ orange stripes

The blue/white pair is pair #1, and the two wires which make up this
pair are twisted around each other. The orange/white pair is pair #2,
and are likewise twisted around each other. If you've got 4-pair cable
(pretty common), pairs 3 & 4 will be green-white and brown-white (I hope
I got that right). The color code goes on for hundreds of combinations.
This kind of cable is commonly known as UTP (Unshielded Twisted Pair).

Older houses might have "quad" cable, which has 4 wires colored red,
green, black, and yellow. Pair #1 is red/green, pair #2 is
black/yellow. You don't see this much any more. Its fine for voice,
but I'm not sure DSL can run over quad cable (because the wires are not
twisted into pairs, the electrical characteristics are inferior to the
twisted pair cable described above).

Now I'm confused. Is my DSL running at higher frequencies, over the same
(single) wire strand that my voice is running on?

Ugh. Again, not sure what to make of this. Your voice service is not
running on a "single wire strand", it's running on a single pair. The
most common type of residential service has two pairs going to your
house. As originally envisioned, the second pair would be used for a
second phone line, or possibly as a spare if the first one went bad.

Depending on how the local telco and DSL providers get along, your DSL
service might be on the same pair as your phone service, or it might be
on the other pair. In either case, it is certainly running at higher
frequencies.

Robert Moore wrote:
"Montblack" wrote

Now I'm confused. Is my DSL running at higher frequencies, over
the same (single) wire strand that my voice is running on? Or is
it running on the second wire strand, in my standard household
wire - which contains 2 wire strands? Or is it using both
strands?


Do you know something that I don't?

How does anything electrical work with only one wire
(conductor)?

Hmmm....maybe my 1950's electrical engineering studies
at Georgia Tech are outdated.

Bob Moore
see
http://computer.howstuffworks.com/dsl2.htm

A simple explanation.


WW

Montblack wrote:

The DSL person explained it to me that each household phone line actually
had two wires in it - DSL uses one, voice the other. I think my "strand"
count is off by a factor of 2(?). More?

The DSL person may have not used precisely correct terminology. The phone
service line (the "network interface"), and the phone wiring within the
house, each have 4 conductors (provided the house was wired within the last
~35 years). By industry standard, these 4 conductors are colored red, green,
yellow, and black, and are paired red-green and yellow-black. The primary
(or only) phone number ("line") in a household will invariably be assigned to
red-green. The secondary phone line will be assigned to yellow-black. In
some neighborhoods, one can get a second phone activated simply by purchasing
a 2-to-1 phone adapter and calling Ma Bell for a phone computer change.

Russell Kent

"Montblack" wrote:
The DSL person explained it to me that each household phone line actually
had two wires in it - DSL uses one, voice the other.

If that's what he said, he's wrong.

Here's what I really know about DSL ....$44 per month.

To be honest, that's all you should really need to know. The key to
making technology usable by the public is to make it simple to use.
Take this box, plug it in, send us $44/month. Sounds about the right
level of complexity to me.

Montblack wrote:

My comment was home phone "wire" (singular) + DSL wire (singular) = 1
standard household phone wire pair. Maybe could have been more clear. I
meant "each" wire inside the pair. You (and Peter Gottlieb) read 2 separate
pair of wires - I think.

There's no way any phone service can use a single wire. Phone service, like
electrical service, requires two or more conductors. In phone parlance, this is
a "loop". In electrical parlance, this is a power and neutral. Now. The typical
"drop", that is, the cable coming into your house, contains four wires. Enough
for two telephones.

Now I'm confused. Is my DSL running at higher frequencies, over the same
(single) wire strand that my voice is running on?

Most (or all) DSL uses higher frequencies than voice and runs on the same wire
pair as your voice connection. I have never heard of a subscriber DSL line that
requires 4 wires, though some other types of digital lines do.

George Patterson
Brute force has an elegance all its own.

Russell Kent wrote:

The DSL person may have not used precisely correct terminology.

The DSL person didn't know his ass from a hole in the ground.

George Patterson
Brute force has an elegance all its own.

"G.R. Patterson III" writes:



Roy Smith wrote:

Of course, it doesn't always work that way. I remember something like
10-15 years ago, a major long-distance switch in Manhattan went down.

I was working for Bell Communications Research at the time. As I recall, it
was a CEV containing multiplexing and digitizing equipment. A lot of Wall
Street traffic went through there. It did not have its own backup generators,
and, as you stated, someone disabled the alarm after it went off. Normally,
field crews would be sent out with portable generators before shutting the
alarm off, but someone screwed up.

I believe Roy is referring to the ATT toll tandem and DACS. There
is a very bitter irony to the story. ATT had a deal with ConEd to
"load shed" ie if ConEd got overworked, ATT would go to diesel for
short periods to ease the strain. {Many large customers have similar
deals; they get big price breaks for doing so..}

ConEd called, ATT shed load, and later returned to the grid.
BUT..several of their rectifiers ('battery chargers') on that floor
failed to restart. The trouble was, none of the power people were
there -- as they were all at a training session .... for the new
power failure monitoring system...

By the time a power employee got back and heard the alarm, the
batteries were too near exhausting to recover. It took hours to
bring everything back up, during which all three NYC airports were
down since the DACS [an electronic patch panel for leased circuits]
ran all of FAA's circuits.

One result was a crack in the FTS2000 sole-source contract. This
debacle forced OMB to allow FAA to rent some service from others.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Newps writes:



Montblack wrote:



Now I'm confused. Is my DSL running at higher frequencies, over the same
(single) wire strand that my voice is running on? Or is it running on the
second wire strand, in my standard household wire - which contains 2 wire
strands? Or is it using both strands?

It takes two wires to have a voice line. There are typically 4 wires in
a residential phone line; red, green, yellow and black.

There are 4 wires in older INSIDE WIRING IN YOUR HOUSE. That's
different from the outside plant from the CO to your house.

Normally the
first phone number uses the red and green wires. The other two will be
for your second phone number, should you get one. The DSL uses the same
two wires as your first phone number, with a filter to keep the two
things separate.

And if your IW is newer, it's likely 3-4 pair; blue/white & white/blue;
orange/white [etc], greeen/white, & brown/white...

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433