The Telecom Digest for December 09, 2010
Volume 29 : Issue 332 : "text" Format
Messages in this Issue:
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Date: Tue, 7 Dec 2010 23:34:22 -0500
From: Monty Solomon <monty@roscom.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Factors affecting social networking site use
Message-ID: <p0624081cc924baf13473@[10.0.1.2]>
First Monday, Volume 15, Number 12 - 6 December 2010
Factors affecting the frequency and amount of social networking site
use: Motivations, perceptions, and privacy concerns
Jiyoung Cha
Abstract
The purpose of this study is to explore the factors that affect the
use of social networking Web sites. In doing so, this investigation
focuses on two dimensions of social networking site use frequency
(i.e., how often people use social networking sites) and amount
(i.e., how much time people spend on social networks). Integrating
the technology acceptance model with uses and gratification and other
consumer characteristics, this study found that interpersonal
utility, perceived ease of use, privacy concerns, and age predict the
frequency of social networking site use. Interpersonal utility
motive, escape motive, and Internet experience explain the time spent
on social networking sites.
...
http://firstmonday.org/htbin/cgiwrap/bin/ojs/index.php/fm/article/view/2889/2685
Date: Tue, 7 Dec 2010 23:36:24 -0500
From: Monty Solomon <monty@roscom.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Sharing music files: Tactics of a challenge to the industry
Message-ID: <p0624081dc924bb7352e8@[10.0.1.2]>
First Monday, Volume 15, Number 12 - 6 December 2010
Sharing music files: Tactics of a challenge to the industry
Brian Martin, Chris Moore, Colin Salter
Abstract
The sharing of music files has been the focus of a massive struggle
between representatives of major record companies and artists in the
music industry, on one side, and peer-to-peer (p2p) file-sharing
services and their users, on the other. This struggle can be analysed
in terms of tactics used by the two sides, which can be classified
into five categories: cover-up versus exposure, devaluation versus
validation, interpretation versus alternative interpretation,
official channels versus mobilisation, and intimidation versus
resistance. It is valuable to understand these tactics because
similar ones are likely to be used in ongoing struggles between users
of p2p services and representatives of the content industries.
...
http://firstmonday.org/htbin/cgiwrap/bin/ojs/index.php/fm/article/view/2986/2680
Date: Tue, 7 Dec 2010 23:37:47 -0500
From: Monty Solomon <monty@roscom.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Twitter content classification
Message-ID: <p0624081fc924bbdb6b68@[10.0.1.2]>
First Monday, Volume 15, Number 12 - 6 December 2010
Twitter content classification
Stephen Dann
Abstract
This paper delivers a new Twitter content classification framework
based sixteen existing Twitter studies and a grounded theory analysis
of a personal Twitter history. It expands the existing understanding
of Twitter as a multifunction tool for personal, profession,
commercial and phatic communications with a split level
classification scheme that offers broad categorization and specific
sub categories for deeper insight into the real world application of
the service.
...
http://firstmonday.org/htbin/cgiwrap/bin/ojs/index.php/fm/article/view/2745/2681
Date: Tue, 7 Dec 2010 23:42:57 -0500
From: Monty Solomon <monty@roscom.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Mobile Health 2010
Message-ID: <p06240821c924bd3fbe9b@[10.0.1.2]>
Mobile Health 2010
by Susannah Fox
Oct 19, 2010
Pew Research Center's Internet & American Life Project
OVERVIEW
The online health-information environment is going mobile. 17% of
cell phone users have used their phone to look up health or medical
information and 9% have software applications or "apps" on their
phones that help them track or manage their health.
ABOUT THE SURVEY
The results in this report are based on data from telephone
interviews conducted by Princeton Survey Research Associates
International between August 9 and September 13, 2010, among a sample
of 3,001 adults, age 18 and older. Interviews were conducted in
English and Spanish and included 1,000 cell phone interviews. For
results based on the total sample, one can say with 95% confidence
that the error attributable to sampling is plus or minus 2.5
percentage points. For results based on Internet users (n=2,065) and
cell phone users (n=2,485), the margin of sampling error is plus or
minus 3 percentage points.
...
http://www.pewinternet.org/Reports/2010/Mobile-Health-2010.aspx
http://www.pewinternet.org/Reports/2010/Mobile-Health-2010/Overview.aspx
Date: Tue, 07 Dec 2010 22:00:31 -0800
From: Thad Floryan <thad@thadlabs.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: 586A/586B/586C (was: Re: Another odd question)
Message-ID: <4CFF1EFF.8040508@thadlabs.com>
On 12/7/2010 5:08 PM, Bill Horne wrote:
> This seems to be a day for odd questions, and I just thought of one.
>
> The Ethernet plugs we use at work are wired for the "568B" standard,
> with the orange wires on pins 1 and 2, and the green wires on pins 3
> and 6.
>
> Here's the question: _why_? I've been told that the whole idea with
> Ethernet is to avoid "Near end crosstalk", so it seems to me that the
> best way to do that would be to put one pair on pins one and two, and
> the other on pairs seven and eight. How did we wind up with 568B?
568B supersedes 568A. 568B is also known as "AT&T Configuration" and is
common in wired installations. 568A, when still found, is typically in
jumper cables. 568B is essentially mandatory for 100 Mbps and faster.
Both 568A and 568B are now superseded by 568C as of February 2009. :-)
Brief details of that can be found in this document:
http://www.tiaonline.org/standards/about/documents/StarReport_09-10.pdf
Search for 568 in the above PDF for some background. Here's a brief clip
copy'n'pasted from page 21 of that PDF:
"
" In February 2009, TR-42 published a new
" standard: ANSI/TIA-568C.0, Generic Telecommunications
" Cabling for Customer Premises.
" This publication created a foundation for three
" types of documents (common standards,
" premises standards and component standards)
" and now becomes the TR-42 standard covering
" cabling topologies, design, distances and
" outlet configurations, as well as specifics for
" cabling infrastructure in all locations. Later In
" 2009, TR-42 published the ANSI/TIA-568-C.2,
" Balanced Twisted-Pair Telecommunications
" Cabling and Components Standard, covering
" the component and performance requirements
" for balanced twisted-pair cabling.
" [...]
" TIA-568-C.1 was published with
" TIA-568-C.0. The publication of ANSI/TIA-568-C.2,
" Balanced Twisted-Pair Telecommunications
" Cabling and Components Standard, completed
" the third revision of the 568 standard, since
" ANSI/TIA-568-C.3, Optical Fiber Cabling Components
" Standard, was published in 2008.
A simple diagram comparing 568A and 568B is here:
http://www.pera.net/Images/Category_5_Diagram.gif
Unfortunately, copies of ANSI standards cost big bucks; the (expletive
deleted) standard for tripod camera attachments cost me US$35 IIRC and
that was only ~15 pages.
Date: Wed, 08 Dec 2010 17:18:49 +1100
From: David Clayton <dcstar@myrealbox.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Pre-natal mobile phone use leads to naughty kids
Message-ID: <pan.2010.12.08.06.18.48.907179@myrealbox.com>
http://www.itwire.com/your-it-news/mobility/43753-pre-natal-mobile-phone-use-leads-to-naughty-kids
Pre-natal mobile phone use leads to naughty kids
By Anthony Caruana
Tuesday, 07 December 2010 16:40
Your IT - Mobility
Danish research has identified a potential link between mobile phone use
by pregnant mums and their children, linking this to the development of
behavioural problems. According to the study, children exposed to mobile
phones before birth and who used phones before the age of 7 were 50% more
likely to have behavioural problems, while those who were exposed to
mobile phones only before birth had a 40% increased likelihood of
behavioural problems.
The study, published in the Journal of Epidemiology and Community Health,
ran from March 1996 to November 2002. It followed nearly 100,000 pregnant
mothers who completed a detailed questionnaire on lifestyle factors,
dietary habits and environmental exposures. When their children were seven
years old, they were questioned again on information pertaining to the
health of her child, cell phone use among children as well as among the
mothers during pregnancy.
The study found that "There is an association between prenatal as well
as postnatal use and behavioural problems by age 7 years among a general
population of mothers who are cell phone users. These results replicate
the findings of an association observed among only early technology
adopters. These new results also reduce the likelihood that these are
chance findings or findings that did not adequately consider the influence
of other important factors for behavioural problems. These results should
not be interpreted as demonstrating a causal link between cell phone use
and adverse health effects for children, but if real - and given the
nearly universal use of cell phones - the impact on the public's health
could be of concern."
In other words, there is a correlation but not necessarily a causal
effect.
Professor Rodney Croft, Executive Director of the Australian Centre for
Radio Frequency Bioeffects Research and a Professor of Health Psychology
at the University of Wollongong, said that "Although this new study is
interesting in that it reports greater behavioural problems in 7-year-olds
whose mothers reported more mobile phone use during pregnancy (than in
those who reported less mobile phone use), the data is not strong enough
to indicate that prenatal mobile phone exposure causes behavioural
problems in children". Professor Croft's main concern is that the
nature of the study relied on parental "parental recall of mobile phone
use" and that this may not have been particularly accurate or
measurable.
>From the other side of the world, Professor Patricia McKinney, Emeritus
Professor of Paediatric Epidemiology at the University of Leeds, said that
"The conclusions from this large study, associating behavioural problems
in very young children with mobile phone use, over-interpret the results.
There is no scientific basis for investigating exposure of the growing
baby when pregnant mothers use a mobile phone, as exposure to
radio-frequency radiation from mobile phones is highly localised to the
part of the head closest to the phone; there is no evidence to suggest
that other parts of the body, such as the abdomen where the baby is
growing, are affected by mobile phone use".
Similarly Professor David Spiegelhalter, Professor of Biostatistics at the
University of Cambridge, said he was "skeptical of these results".
Date: Wed, 8 Dec 2010 02:34:44 +0000 (UTC)
From: wollman@bimajority.org (Garrett Wollman)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Another odd question
Message-ID: <idmqs4$2cji$1@grapevine.csail.mit.edu>
In article <20101208010810.GB3356@telecom.csail.mit.edu>,
Bill Horne <bill@horneQRM.net> wrote:
>Here's the question: _why_? I've been told that the whole idea with
>Ethernet is to avoid "Near end crosstalk", so it seems to me that the
>best way to do that would be to put one pair on pins one and two, and
>the other on pairs seven and eight. How did we wind up with 568B?
Early on, there was an idea that you might want to put a voice pair on
4/5. Then an eight-position modular plug wired for single-line voice
would work if plugged in to a data line. I suppose if you were
running the original AT&T StarLAN over category-3 wiring, this might
have worked. AIUI, MIT's internal phone wiring is still done very
much like that: all the home runs end up at a distribution frame in
the closet, and then are cross-connected to analog voice, ISDN, or an
Ethernet switch. (We run our own network in my building, and we use
VoIP, so all of that wiring lies fallow in the nearly-empty phone
closets.)
Gigabit Ethernet (and higher speeds) require all four pairs, and in
fact use them bidirectionally. (That's why "crossover" cables are no
longer useful.)
-GAWollman
Disclaimer reinformcement: I may work for MIT, but they don't pay me
enough to speak for them.
--
Garrett A. Wollman | What intellectual phenomenon can be older, or more oft
wollman@bimajority.org| repeated, than the story of a large research program
Opinions not shared by| that impaled itself upon a false central assumption
my employers. | accepted by all practitioners? - S.J. Gould, 1993
Date: Wed, 08 Dec 2010 07:14:17 -0600
From: bonomi@host122.r-bonomi.com (Robert Bonomi)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Another odd question
Message-ID: <9OWdnSwXYMQ0GWLRnZ2dnUVZ_rqdnZ2d@posted.nuvoxcommunications>
In article <20101208010810.GB3356@telecom.csail.mit.edu>,
Bill Horne <bill@horneQRM.net> wrote:
>This seems to be a day for odd questions, and I just thought of one.
>
>The Ethernet plugs we use at work are wired for the "568B" standard,
>with the orange wires on pins 1 and 2, and the green wires on pins 3
>and 6.
>
>Here's the question: _why_? I've been told that the whole idea with
>Ethernet is to avoid "Near end crosstalk", so it seems to me that the
>best way to do that would be to put one pair on pins one and two, and
>the other on pairs seven and eight. How did we wind up with 568B?
We 'wound up' with 568B because people didn't like 568A. <grin>
The 8P8C pin-out is 'upward compatible' with the RJ-11/-14, so 'pair 1'
is on the center pins (4 & 5), 'pair 2' is the 'surrounding' pair (3 & 6),
and the remaining 2 'pairs' were put on sets of adjacent pins (1&2 , 7&8).
10-Base-T Ethernet was designed to share a 4-pair cable with a phone
line. the phone is on pair 1, for compatibility, and 'data' went on
pairs 2 and 3.
Now, -if- the two Ethernet pairs were on 1&2, 7&8, the separation between
'tip' in the two pairs would have been the same as the separation between
'ring' in the two pairs. Meaning the inductive coupling would have been
roughly _equal_, effectively _maximizing_ the induced signal in the
differential circuit. By placing the conductors ad -different- distances,
one gets different amounts of induced signal in each wire -- this leads
to the 'excess' amount on one wire being 'ignored' by the differential
receiver, so that, effectively, only the lesser of the two induced
signals is 'seen' by the attached equipment.
Date: Tue, 07 Dec 2010 23:32:12 -0500
From: Eric Tappert <e.tappert.spamnot@worldnet.att.net>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: A question about CO wiring
Message-ID: <ik1uf6d0rck9j6igasufgi4enev68bpf54@4ax.com>
On Tue, 07 Dec 2010 20:25:28 -0500, Bill Horne <bill@horneQRM.net>
wrote:
>I've been working for a company that sells a line-switching device for
>use by the utility industry. We routinely get boxes returned to us
>that have been fried by voltage spikes, and it occurs to me that a
>central office must take a lot of surges, spikes, etc. That's a
>paradox, because I never heard of a CO being damaged by anything but a
>direct lightning hit the whole time I was a tech.
>
>We had, of course, "carbons" and "heat coils" at the frame that were
>intended to take care of spikes coming in on the cable, but to gauge
>by the way today's electronic boxes get burned up so easily, I'm
>really surprised we didn't have a lot more trouble with lightning.
>Ergo, I'm wondering what other equipment was used to keep the CO's
>from suffering at Zeus' hands.
>
>Bill
Bill,
The old electomechanical switches (including the analog ESS) were
pretty much immume from anything that got through the carbon blocks.
The heat coils were for overcurrent protection due to a short in the
cable plant.
Modern digital line cards have "secondary protection" circuits which
are specifically design to deal with anything that can get past the
gas tubes that replaced the carbon blocks. Don't forget the gas tubes
short the pair to ground when activated (as did the carbon blocks).
Gas tube protectors are more closely controlled as to breakover
voltage than the old carbon blocks. That and maintenance issues are
the reason they replaced the carbon blocks. This secondary protection
often uses high voltage tolerant technology and can be designed to be
very effective. The heat coils are still in place to protect from
shorts in the cable plant, but modern digital line cards also current
limit the loop current to something in the 20-40 mA range.
CO bonding and grounding is also very good compared to most subscriber
locations.
Of course the cable plant is shielded (except, perhaps, the drop) and
twisted to minimize capacitive and inductive coupled surges. Where
poles are shared, then the power company conductors are above the
telco wiring, acting as one of old Ben Franklin's lightning rods...
Underground cable sees large surges only in the area of a strike being
grounded, so they see less of the effect of lightning.
In short, if things are properly designed for the environment, then
things short of a direct strike are usually pretty harmless.
BTW, subscriber telephones seem to do pretty well behind the telco
protection blocks (at least the good ones)....
Perhaps the boxes you see are being fried by power line surges (which
can be large due to either switching actions at substations or power
line faults). COs run on batteries and have some decent isolation
from power line surges.
ET
--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
Date: Wed, 08 Dec 2010 17:16:32 +1100
From: David Clayton <dcstar@myrealbox.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: A question about CO wiring
Message-ID: <pan.2010.12.08.06.16.29.335749@myrealbox.com>
On Tue, 07 Dec 2010 20:25:28 -0500, Bill Horne wrote:
..........
> We had, of course, "carbons" and "heat coils" at the frame that were
> intended to take care of spikes coming in on the cable, but to gauge by
> the way today's electronic boxes get burned up so easily, I'm really
> surprised we didn't have a lot more trouble with lightning. Ergo, I'm
> wondering what other equipment was used to keep the CO's from suffering at
> Zeus' hands.
>
I know for a fact that all incoming connections in Australian COs are
protected by heavy duty surge protection devices (and have been since the
exchange equipment went digital decades ago). These devices clipped
directly onto the Krone termination blocks along with a good ground
connection.
These will protect the electronic exchange ports from anything bar a
direct hit, but at the other end of the cables things like ADSL modems
will just get progressively degraded by induced spikes if they do not have
some protection.
One just has to frequent various forums and see the posts of people
complaining about their ADSL services immediately after storm activity in
their local area, but it takes a while for them to stop blaming their
ISP and realise that their equipment "...but it's been working perfectly
for years..." is the problem.
--
Regards, David.
David Clayton
Melbourne, Victoria, Australia.
Knowledge is a measure of how many answers you have, intelligence is a
measure of how many questions you have.
Date: Wed, 08 Dec 2010 08:38:19 -0600
From: bonomi@host122.r-bonomi.com (Robert Bonomi)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: A question about CO wiring
Message-ID: <7tqdnQyxXd3GBWLRnZ2dnUVZ_hydnZ2d@posted.nuvoxcommunications>
In article <E1PQ8me-0001Il-CM@telecom.csail.mit.edu>,
Bill Horne <bill@horneQRM.net> wrote:
>I've been working for a company that sells a line-switching device for
>use by the utility industry. We routinely get boxes returned to us
>that have been fried by voltage spikes, and it occurs to me that a
>central office must take a lot of surges, spikes, etc. That's a
>paradox, because I never heard of a CO being damaged by anything but a
>direct lightning hit the whole time I was a tech.
>
>We had, of course, "carbons" and "heat coils" at the frame that were
>intended to take care of spikes coming in on the cable, but to gauge
>by the way today's electronic boxes get burned up so easily, I'm
>really surprised we didn't have a lot more trouble with lightning.
>Ergo, I'm wondering what other equipment was used to keep the CO's
>from suffering at Zeus' hands.
There are only about two things one can do to 'protect' equipment from
spikes/surges/etc.:
1) give the 'excess' voltage/current a 'more attractive' path to
'ground'.
2) deny it a path 'in'.
(1) typically involves a 'gap' between the cabling and ground. sufficient
to be an effective insulator at 'normal' voltage, but, at moderate
over-voltage, it will 'arc over', and provide a near 'zero-ohm' path
to ground. In the simplest form it is just a calibrated "air gap",
fancier forms use gas discharge conductivity similar to a NE-2 indicator
bulb, or something else that 'avalanches' into conduction when a
threshold is crossed.
(2) is the equivalent of a fuse, albeit in a variety of forms. Upon detection
of the overload condition, it -open- the circuit, preventing the spike
from going further.
Then there are combinations of the above. 'crowbar' circuits are a 'selective'
short to ground, installed 'downstream' of a fuse type device. The crowbar
detects a 'slight' over-voltage, and provides a massive short to ground,
causing an immediate reaction from the circuit interruptor. The radical
increase in the overload brought about by the crowbar causes the interruptor
to react much faster than it would have to just the 'natural' overload
itself.
Date: Wed, 08 Dec 2010 06:38:59 -0600
From: bonomi@host122.r-bonomi.com (Robert Bonomi)
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Question about an old scrambler phone
Message-ID: <tNOdnQFjner-4WLRnZ2dnUVZ_j6dnZ2d@posted.nuvoxcommunications>
In article <AANLkTikNo4yk3iRENuKp_f4QRTgnedkZuknL1PEFju-E@mail.gmail.com>,
Ernest Donlin <ernest.donlin.remove-this@and-this-too.gmail.com> wrote:
>(moderator please change my email address so spammers can't use it.)
>
>I've got an odd sort of a question for your group.
>
>When I was a kid, my friend's dad had a phone in his house that he told me
>was a "scrambler". It was a regular telephone, mounted on a metal
>base, with an AC cord for the base. The base had just two vacuum tubes in
>it, and a couple of transformers. It didn't look like much, but my friend
>said his dad used it to make scrambled phone calls to his reserve unit.
>
>Has anyone ever seen anything like that? I never knew if he was yanking my
>chain or not.
One of the simplest forms of a 'scrambler' simply frequency-inverted the
audio input. basically, use the audio to AM modulate a circa 4kHz 'carrier',
and send only the the lower sideband over the wires..
Conveniently, you can 'unscramble' the signal by doing exactly the same
thing to the 'scrambled' signal.
Necessary components are: 1) an oscillator, 2) a modulator, 3) a low-pass
filter. That's two tubes, and an inductor with a couple of capacitors,
plus a multi-tap (filament and B+) power transformer to run it all.
Sounds real close to what your friend's dad had. <grin>>
Now, to answer the actual question you asked: "No, I've never actually
seen one of them myself." I only know "of" such devices, having read
about, seen schematics in books, etc.
TELECOM Digest is an electronic journal devoted mostly to telecom-
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End of The Telecom Digest (12 messages)
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