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The Telecom Digest for July 05, 2011
Volume 30 : Issue 165 : "text" Format
====== 29 years of TELECOM Digest -- Founded August 21, 1981 ====== |
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Date: Sun, 03 Jul 2011 16:48:41 -0700
From: Sam Spade <sam@coldmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Battery power support today
Message-ID: <LPydnQuNiOBHYo3TnZ2dnUVZ_tSdnZ2d@giganews.com>
David Scheidt wrote:
> Sam Spade <sam@coldmail.com> wrote:
> :David Lesher wrote:
> :> Sam Spade <sam@coldmail.com> writes:
> :>
> :>
> :>>The exception was a pair-gain provision such as the Bell Systems SLC 96,
> :>>which was used in rural areas and in areas of rapid residential
> :>>construction. I believe the terminating SLC 96 box had to have local
> :>>power. Anyone know differently?
> :>
> :>
> :> Oh yes, SLC's need power.
> :>
> :>
> :>>I imagine SLC 96s are long gone for residential suburban areas
> :>>but they likely still exist in some rural areas.
> :>
> :>
> :> I was just in Aptos/Watsonville CA region, and there are
> :> SLC-96's on every other corner. The giveway is the line of
> :> shiny T1 repeater cans feeding same.
>
> :Both of those areas are a mix of suburban and remote rural areas. I can
> :understand the SLC 96 on a road back in the hills of Aptos where the
> :there are long distances with no houses, then a cluster of house. But,
> :if pair gain is being used in the suburban part of Aptos I would think
> :AT&T would be getting heat from the CPUC.
>
> Why? Modern nodes support all the services that are expected, like
> DSL, television, etc. They're fed with high speed backhaul (often
> fiber in dense areas).
One word: concentration. It's been a long time, but my recollection is
that the concentration ratio is 6:1. So, no more than 16 subscribers
out of the 96 that are likely connected in a suburban area will get dial
tone at any given time. For suburban areas SLC 96s were only suppose to
be used until the LEC could provide dedicated subscriber loop.
***** Moderator's Note *****
IIRC, SLC-96's in "Mode 2", at least the way N.E.T. used them, were
able to provide 100% dialtone (within the limits of the associated CO,
of course), because they used "half rate" sampling to allow 48
channels per T-1 span. SLC-96 units had special common boards, and if
they were inserted into "Mode 3" SLC-96 carriers by mistake, a 1000 Hz
test tone would be received at 2000 Hz.
I don't think N.E.T. ever concentrated subscriber lines going through
SLC-96 in a way that would deny dial tone at any time, but that may
have been only in Massachusetts: in the 1960's, the company had
installed electromechanical concentrators to maximize cable usage in
low-profit areas, but the DPU made N.E.T. remove them because of
political backlash.
Bill Horne
Moderator
Date: Sun, 03 Jul 2011 16:50:50 -0700
From: Sam Spade <sam@coldmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Battery power support today
Message-ID: <LPydnQqNiODHnYzTnZ2dnUVZ_tSdnZ2d@giganews.com>
David Lesher wrote:
> The CPUC regulates phone service. They have no control over DSL
> & beyond. It's up to PacBell [1] how they get get dialtone to
> 28 Barbary Line or similar. And since the DS1 fed SLC's are sunk
> cost; why would they change them out?
Thus, they regulate local loop for voice services.
Date: Mon, 04 Jul 2011 17:27:07 +1000
From: David Clayton <dcstarbox-usenet@yahoo.com.au>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: New mobiles study doubts cancer risks
Message-ID: <pan.2011.07.04.07.27.06.76154@yahoo.com.au>
http://www.theage.com.au/technology/technology-news/new-mobiles-study-doubts-cancer-risks-20110702-1gvyo.html
New mobiles study doubts cancer risks
Kristen Hallam
July 3, 2011
MOBILE phones may not increase the risk of brain cancer, a study has
found, just a month after the World Health Organisation said using the
devices may cause tumours.
Studies from several countries have failed to show an increase in brain
tumours, up to 20 years after mobile phones were introduced and 10 years
after the technology became widespread, the International Commission on
Non-Ionizing Radiation Protection's committee on epidemiology wrote in the
journal Environmental Health Perspectives.
The findings of the committee, which included scientists from Australia,
challenge those of an International Agency for Research on Cancer review.
However, the debate is likely to continue because data is limited and
researchers cannot prove the complete absence of an impact on the world's
4.6 billion mobile users.
''This is a really difficult issue to research,'' David Spiegelhalter, the
Winton professor of the public understanding of risk at the University of
Cambridge, said. ''This report is clear that any risk appears to be so
small that it is very hard to detect.''
The International Commission on Non-Ionising Radiation Protection sets
guidelines for exposure limits to radiation, including radio frequency
fields emitted by mobile phones.
The panel reviewed all previous studies on the link between mobile phone
use and brain tumours, including the largest epidemiological study to
date, known as Interphone, which could not find a definite link between
mobile use and certain types of brain tumours.
Last month the International Agency for Research on Cancer, part of the
Geneva-based WHO that classifies cancer risks, said exposure to
radiofrequency electromagnetic fields was greater from handsets than phone
towers and base stations.
Bloomberg
Date: Mon, 04 Jul 2011 01:31:49 -0700
From: Sam Spade <sam@coldmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Battery power support today
Message-ID: <NICdnYhY28br54zTnZ2dnUVZ_gqdnZ2d@giganews.com>
Lisa or Jeff wrote:
> .. Things were even worse going further back in time. (IMHO, the
> above-ground nuclear testing of the 1940s and 1950s didn't help us
> any, but I don't know if anything, such as increased leukemia rates,
> have been documented.)
The late 1940s saw a few tests. The 1950s is where we went nutso, but
in Nevada and the Marshall Island. There was a lot of payoffs and
coverups on the damage caused at the Nevada test site. Hard core
radioactivity is still a great problem there. Not airborne any longer,
but mostly harmless in the soil unless you work there and are unlucky
enough to get some into your lungs.
Date: Sun, 3 Jul 2011 16:57:56 -0700 (PDT)
From: Wes Leatherock <wleathus@yahoo.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: "Underground" demarc?
Message-ID: <1309737476.83461.YahooMailClassic@web111714.mail.gq1.yahoo.com>
--- On Fri, 7/1/11, grumpy44134 <grumpy44134@gmail.com> wrote:
> My friend is having an intermittent problem with her home phone. I
> told her to find the gray demarc/Telephone Network Interface (Ohio)
> box. After not being able to find it, she reminded me her power and
> telephone wires were underground to her house. Question - where is
> the demarc for underground telephone service (in Ohio)?
I couldn't tell you about Ohio, but the buried drop serving me in
Oklahoma rises out of the ground and comes up to the conduit holding
the electric meter (to which it is grounded) and the demarc is at
about eye level, accessible to the customer, as it's supposed to be.
Wes Leatherock
wleathus@yahoo.com
wesrock@aol.com
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