29 Years of the Digest ... founded August 21, 1981
The Telecom Digest for July 05, 2011
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Date: Sun, 03 Jul 2011 16:48:41 -0700 From: Sam Spade <email@example.com> To: firstname.lastname@example.org. Subject: Re: Battery power support today Message-ID: <LPydnQuNiOBHYo3TnZ2dnUVZ_tSdnZ2d@giganews.com> David Scheidt wrote: > Sam Spade <email@example.com> wrote: > :David Lesher wrote: > :> Sam Spade <firstname.lastname@example.org> 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 <email@example.com> To: firstname.lastname@example.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  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 <email@example.com> To: firstname.lastname@example.org. Subject: New mobiles study doubts cancer risks Message-ID: <email@example.com> 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 <firstname.lastname@example.org> To: email@example.com. 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 <firstname.lastname@example.org> To: email@example.com. Subject: Re: "Underground" demarc? Message-ID: <1309737476.83461.YahooMailClassic@web111714.mail.gq1.yahoo.com> --- On Fri, 7/1/11, grumpy44134 <firstname.lastname@example.org> 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 email@example.com firstname.lastname@example.org
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