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Message Digest
Volume 28 : Issue 126 : "text" Format
Messages in this Issue:
Re: Telecom Digest archives questions [TELECOM]
Re: Waveguide (was "size a major consideration...")
Re: Hackers Break Into Virginia Health Professions Database, Demand Ransom
Re: Telecom Digest archives questions [TELECOM]
Re: Hackers Break Into Virginia Health Professions Database, Demand Ransom
====== 27 years of TELECOM Digest -- Founded August 21, 1981 ======
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See the bottom of this issue for subscription and archive details
and the name of our lawyer, and other stuff of interest.
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Date: Wed, 6 May 2009 21:58:25 -0700 (PDT)
From: Thad Floryan <thad@thadlabs.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Telecom Digest archives questions [TELECOM]
Message-ID: <e0bb5598-a23c-4032-a543-ad43dbba8fab@d25g2000prn.googlegroups.com>
On May 6, 9:18 pm, tec...@tantivy.tantivy.net (Bob Vaughan) wrote:
> [...]
> I find mbox to be a very useful format.
>
> One of my major frustrations with Yahoo groups is the lack of any bulk
> download capability, or any way of importing group archives into a
> offline reader, other than saving individual posts.
There is a widely available perl script that downloads en masse
from Yahoo into mbox format.
One caveat is one's Yahoo account can get "locked out" for
awhile if too much is downloaded at one time.
A Google search on "yahoo2mbox" will point you to the perl
program and also many forums discussing how to get-around
Yahoo's restrictions.
***** Moderator's Note *****
Before you go to the trouble, remember that the digest's archives are
already available in mbox format, either from the web page, or from me
if you need something more recent.
Bill Horne
Temporary Moderator
------------------------------
Date: Thu, 07 May 2009 11:31:14 -0500
From: Neal McLain <nmclain@annsgarden.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Waveguide (was "size a major consideration...")
Message-ID: <4A030CD2.1010400@annsgarden.com>
David Lesher <wb8foz@panix.com> wrote:
> I've known of CATV companies that did use some coax backhauls to
> the head end; now fiber rules the nest.
CATV systems commonly used coax to backhaul signals from points within
the distribution system (e.g., municipal buildings, schools, the CATV
company's office) back to the headed for redistribution. But these
signals were usually carried over the same coax network that carried
downstream distribution signals. They were carried in the "subband"
(5-20 MHz) below Channel 2. A hypothetical example:
http://annsgarden.com/telecom/Backhaul.jpg
In this example, a signal is carried upstream to the headend on a
subband channel, and converted at the headend to Channel 13 for
distribution to subscribers.
Thousands of CATV systems also employed coax for "forwardhaul" to
carry signals from the headend to the distribution network. Most of
the early systems were built in mountainous areas where coax was
needed to get signals from the headend on the mountain to the
residents in the valley. In places with relatively flat topography,
CATV companies built tall towers, often outside of town, and used coax
to carry signals to the distribution network.
Example: Hillsdale, Michigan:
http://annsgarden.com/telecom/Hillsdale1.jpg
http://annsgarden.com/telecom/Hillsdale2.jpg
I wrote:
> Nothing unique about that, of course: it's the same modulation scheme
> that AT&T Long Lines had been using for years for their intercity
> relays.
Richard <rng@richbonnie.com> wrote:
> No. To transmit the video of one TV signal, AT&T Long Lines used FM
> modulation of one 20 MHz channel at 4 GHz or 11 GHz or one 29.xx MHz
> channel at 6 GHz. The audio was transmitted separately on other
> facilities using wide-band audio channels which were intermixed with
> regular 4 KHz-wide analog voice circuits. The microwave systems had
> names like TD, TH, TJ, and TL; the "T" meant televison because they
> originaly were designed to capture the television transmission market.
> The wider-band systems at 6 GHz were developed in the late 1950's in
> case high-def TV for theaters was developed.
> When not carrying television, these systems carried 1200 multiplexed
> SSB voice channels (1860 channels for the 6 GHz system).
Did "T" always indicate television? I thought TD could refer to a
group of 1200 multiplexed SSB voice channels.
http://long-lines.net/tech-equip/misc/EOBS84-363.html
In any case, the comparison I was trying to make is that AT&T used SSB
suppressed carrier modulation to combine voice signals into groups. I
understand that AT&T used FM for the microwave link whether it was a
TD group or one video signal.
Frequencies within the CARS band can be used for FM or SSB AM. There
are several frequency plans; the frequency plan I described in my
previous post is Group C. Other Groups (A, B, and K) can be used for
FM. The allocation plan, as defined in the FCC rules at 47 CFR 78, is
at http://tinyurl.com/47CFR78
Many CATV companies used FM transmission in Groups A, B, and K to
carry individual TV channels from remote points back to headends.
Two examples:
- Benton KY to Paducah KY. In this case, an FM CARS link was used to
carry a Nashville TV station, received off-the-air in Benton, to the
CATV system in Paducah.
http://annsgarden.com/telecom/Paducah.jpg
- North Bergen NJ to Lyndhurst NJ. In this case, an FM CARS link was
used to carry a Philadelphia TV station, received off-the-air in North
Bergen, to the CATV system in Lundhurst. Even though Lyndhurst is
actually closer to Philadelphia than North Bergen, the difference in
elevation between North Bergen (210 feet) and Lyndhurst (20 feet) made
the link necessary.
http://annsgarden.com/telecom/Lyndhurst.jpg
The transmitter at North Bergen was located on the top floor of a
multistory apartment building, inside an apartment that the CATV
company rented. The equipment racks were in the living room, and the
antennas were installed on the balcony. The whole thing came to an
abrupt end in 1982 when a fire broke out in the apartment. It must
have been a big fire: when I visited the site a few days later,
everything in the apartment was black, the glass balcony doors were
broken, and the aluminum antenna reflectors looked like Salvadore
Dali's pocket watches.
Neal McLain
***** Moderator's Note *****
I didn't do a lot of work on microwave, but I _was_ trained in "L"
carrier. What little I remember was that one L carrier Mastergroup
needed one coaxial cable, and that a single TV channel _also_ required
a coaxial cable to itself.
The coax had noticeable transit delays when used for TV, which were
long enough that Huntley and Brinkley had to use a carefully-crafted
set of "handoff" cues to compensate, so that one had to start talking
a couple of seconds before the other one stopped: I don't know if
Microwave eliminated the problem.
I think TV signals that traveled on coax included multiplexed audio in
later years, although I'm not familiar with the modulation scheme that
was used.
Bill Horne
P.S. Please try to send "Plain Text" emails to the Digest, or the
StripMime software will remove the HTML and "format" your
submission in a way you may not care for.
--- StripMime Report -- processed MIME parts ---
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text/html
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Bill Horne
Temporary Moderator
------------------------------
Date: Thu, 07 May 2009 17:39:03 +1000
From: David Clayton <dcstar@myrealbox.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Hackers Break Into Virginia Health Professions Database, Demand Ransom
Message-ID: <pan.2009.05.07.07.39.02.823737@myrealbox.com>
On Wed, 06 May 2009 07:34:08 -0400, Monty Solomon wrote:
> Hackers Break Into Virginia Health Professions Database, Demand Ransom
>
> By Brian Krebs
>
> Washington Post
> May 4, 2009
>
> Hackers last week broke into a Virginia state Web site used by
> pharmacists to track prescription drug abuse. They deleted records on
> more than 8 million patients and replaced the site's homepage with a
> ransom note demanding $10 million for the return of the records,
> according to a posting on Wikileaks.org, an online clearinghouse for
> leaked documents.
Or the organisation merely restores the data from their daily backup for
just the cost of time and inconvenience. At worst one day's changes may be
lost - hardly worth $10M.
--
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.
***** Moderator's Note *****
The amount they demanded was just for bragging rights: it was crack by
some script kiddie who didn't have much imagination, plus the usual
"If it bleeds, it leads" fearmongering by the television stations.
If he had had the brains to demand a more realistic amount - say,
$3,000 - _then_ it would have gotten interesting.
Bill Horne
Temporary Moderator
------------------------------
Date: Thu, 7 May 2009 11:50:33 -0700 (PDT)
From: hancock4@bbs.cpcn.com
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Telecom Digest archives questions [TELECOM]
Message-ID: <6f6382b0-ea70-423d-9279-9bc05753a030@b1g2000vbc.googlegroups.com>
On May 6, 7:35 am, John Mayson <j...@mayson.us> wrote:
Regarding the archives, I would like to say that having the Western
Union Technical Review and other materials are a major asset.
Those who built and maintain these archives deserve a big THANKS.
> I remember when we had The Phone Company and would wait until 11 PM to
> call our grandparents to save on toll charges. Comparing 1981 to 2009
> is really stunning.
As an aside, that 11 pm discount time was originally midnight; then
they moved it to 11 pm. The 11 pm discount, was part of a new major
long distance rate overhaul. IIRC, at that time introduced (1) a
third large discount period (in addition to day and evening) and (2)
one minute charging instead of the three minute minimum, and (3)
applied to dial-direct calls only, operator handled calls cost more.
This was introduced in the early 1970s that reflected virtually the
whole country had DDD. (Those that didn't have DDD and those who had
trouble placing a call and needed operator help still were charged DDD
rates.)
It is important to note this was a major rate reduction. Critics of
the old Bell System who claim divesture and "competition" was
necessary to reduce toll rates ignore measures like this.
------------------------------
Date: Thu, 07 May 2009 18:29:20 -0800
From: John David Galt <jdg@diogenes.sacramento.ca.us>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Hackers Break Into Virginia Health Professions Database, Demand Ransom
Message-ID: <gu01s1$r44$1@blue.rahul.net>
> Hackers last week broke into a Virginia state Web site used by
> pharmacists to track prescription drug abuse. They deleted records on
> more than 8 million patients and replaced the site's homepage with a
> ransom note demanding $10 million for the return of the records,
> according to a posting on Wikileaks.org, an online clearinghouse for
> leaked documents.
The state should simply pay the ransom, then have police on-scene when
the money is delivered. There's no way the bad guy(s) can collect it
without exposing themselves; that's why kidnapping for money no longer
occurs in the US.
***** Moderator's Note *****
Maybe they planned on having it sent through PayPal ...
If I were doing that kind of work, I would approach the organization
that had been hacked, and offer a "No cure, no pay" contract to
recover the data for some relatively minor amount. Assuming they were
willing to sign, I'd produce a miracle cure, send them a bill, and
make it my business to never, ever rub their nose in it.
Bill Horne
Temporary Moderator
------------------------------
TELECOM Digest is an electronic journal devoted mostly to telecom-
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End of The Telecom digest (5 messages)
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