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Message Digest
Volume 28 : Issue 136 : "text" Format
Messages in this Issue:
Re: Verizon selling off phone lines
Re: Verizon selling off phone lines
Re: CO backup power (was Re: FiOS in MDU Buildings)
Re: CO backup power (was Re: FiOS in MDU Buildings)
Re: Verizon selling off phone lines
Re: Verizon selling off phone lines
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Date: Mon, 18 May 2009 10:44:26 -0400
From: Fred Goldstein <fgoldstein.SeeSigSpambait@wn2.wn.net>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Verizon selling off phone lines
Message-ID: <20090518144251.3C8FE48077@mailout.easydns.com>
On Sun, 17 May 2009 07:54:01 -0700, Sam Spade <sam@coldmail.com> wrote,
> >>Western Electric were primarily interested in large multi-office
> >>cities where common control capabilities were needed, and [were] not
> >>much interested in smaller places where SxS was not only adequate but
> >>in many ways superior.
> >
> >
> > Certainly SxS was superior for smaller offices. Common control
> > required considerable overhead and was thus uneconomical in smaller
> > offices.
> >
> > Nonetheless, the Bell Labs history on switching documents many
> > improvements made to the Strowger unit over the years, [to improve]
> > SxS offices. [For example,] in the 1960s electronic front ends were
> > added to improve efficiency.
>
>Before that Pacific Telephone, for one BOC, added a No, 5 XBAR unit as
>the common control unit for giant, old SxS offices (Pasadena and Los
>Angeles Madison come to mind) and the XBAR also served as a local office
>code expansion unit.
>
>GTE, OTOH, [chose] this terrible "director" unit, which failed terribly
>under traffic loads, and this went on for years in the LA area. The
>subscriber could make a non-toll call just fine, but on a toll call he
>could wait up to 90 seconds for an ATB signal to appear.
>
>***** Moderator's Note *****
>
>I'd like to hear more about using a #5 for common control with a SxS
>office: I didn't know that was possible until now.
Going on folklore (not having worked "inside" Ma, but having random
sources...)...
Panel offices had a bit of what might be considered common control;
it used a "decoder" to route calls baed on the first three digits
dialed. Some time later, "directors" were added to some step offices
to add similar capabilities, but most step offices didn't have
them. Panel had a higher entry cost, of course, and thus was only
used in urban markets. Here's the rub: Panel's trunk signaling was
incompatible with step; they could not directly have trunks to each
other. So a stepper market (like Los Angeles) generally had no panel
offices in it. But sometimes a panel market had both, such as
suburbs with step near a panel city. In such cases, they could only
interconnect indirectly. That was the role of the crossbar tandem.
So there were many more tandem offices in the past than there are
now. The crossbar in Pasadena was probably considered to be a
metropolitan (not toll) tandem. Some of these crossbar tandems had
the card translator units, which made them *extra* loud! (Metal
punch cards, IIRC about 10x6 inches, had holes punched in them and
notches on the bottom, corresponding to prefix codes, and metallic
probes read them as they dropped when the notches matched. Or
something like that.)
When electronic switching came in and panels were gone, the number of
tandems went way down. Looking at a 1982 (before the 4ESS/5ESS/DMS
digital tandems) New England Telephone list, Massachusetts had two
tandems in Brockton (Class 3 and 4 4A and XBT crossbars), two in
Cambridge (4A crossbar and a 1ESS), one in Dorchester (crossbar), one
in Fall River (crossbar), two in Framingham (4A and XBT), four in
Boston-Franklin (CAMA XBT, Long Lines 4A, toll XBT and Metro XBT),
one in Boston-Harrison (XBT), two in Lawrence (4A and XBT), one in
Malden (XBT), one in Newton (XBT), one in Springfield (Long Lines,
the state's first 4E), and two in Worcester (4A and XBT). That's
about 20 switches. But the XBTs were almost all marked for removal
in 1982. There were no panels left and big 4Es were on the way.
By the time of divestiture, the only tandems were Cambridge,
Lawrence, Brockton, Framingham, Worcester and Springfield. A new one
in Newton was added during the dial-up boom a decade ago, and
Cambridge has two. The IXC networks, of course, are totally separate.
This Flickr collection (by "PanelSwitchman", bless him whoever he may
be) has an amazing collection of photos of old CO gear in service,
including detail shots of panel, with some explanatory text.
http://www.flickr.com/photos/9479603@N02/
--
Fred Goldstein k1io fgoldstein "at" ionary.com
ionary Consulting http://www.ionary.com/
+1 617 795 2701
***************** Moderator's Note *********************
The picture of the Type 206 Rotary Switch
(http://www.flickr.com/photos/9479603@N02/1814564983/) reminded me of
the Japenese "PURPLE" Cipher machine used during World War II, which
was reported to use similar switches: I think it was the only
electromechanial cipher device that was never replicated - probably
because a complete machine never fell into Allied hands.
This might seem a curious remark, given the subject of this thread,
but bear with me: I once met a man at the labs who was reponsible for
predicting future traffic patterns in the Bell System, and for
recommending new switch configurations. A friend told me that he had
been a cryptographer in Vietnam, and when I asked him about it, he
said that traffic analysis and cryptography were both the same
process.
------------------------------
Date: Mon, 18 May 2009 22:48:07 -0400
From: T <kd1s.nospam@cox.nospam.net>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Verizon selling off phone lines
Message-ID: <MPG.247be7f5bd6484cf989a1e@reader.motzarella.org>
In article <20090518144251.3C8FE48077@mailout.easydns.com>,
fgoldstein.SeeSigSpambait@wn2.wn.net says...
> When electronic switching came in and panels were gone, the number
> of tandems went way down. Looking at a 1982 (before the
> 4ESS/5ESS/DMS digital tandems) New England Telephone list,
> Massachusetts had two tandems in Brockton (Class 3 and 4 4A and XBT
> crossbars), two in Cambridge (4A crossbar and a 1ESS), one in
> Dorchester (crossbar), one in Fall River (crossbar), two in
> Framingham (4A and XBT), four in Boston-Franklin (CAMA XBT, Long
> Lines 4A, toll XBT and Metro XBT), one in Boston-Harrison (XBT), two
> in Lawrence (4A and XBT), one in Malden (XBT), one in Newton (XBT),
> one in Springfield (Long Lines, the state's first 4E), and two in
> Worcester (4A and XBT). That's about 20 switches. But the XBTs
> were almost all marked for removal in 1982. There were no panels
> left and big 4Es were on the way.
How about RI? I know we had a mix of #5XB, Panel, and SxS but not aware
of any tandems. Most of the metro area was served by either Panel
(Providence) or XB (Pawtucket, Cranston, Warwick).
------------------------------
Date: 18 May 2009 15:13:50 -0000
From: John Levine <johnl@iecc.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <20090518151350.57844.qmail@simone.iecc.com>
>memory. One option, not found on the 312 I worked with, was a
>motor/generator hooked to the other end of the drum ...
Motor/generators were fairly common with large mainframes. In
the late 1960s the IBM 360/91 supercomputer included one.
R's,
John
------------------------------
Date: 18 May 2009 12:57:42 -0400
From: adykes@panix.com (Al Dykes)
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: CO backup power (was Re: FiOS in MDU Buildings
Message-ID: <gus426$h2n$1@panix5.panix.com>
In article <nP1Ql.44844$Rf7.37399@newsfe21.iad>,
Dr. Barry L. Ornitz <BLOrnitz48@charter.net> wrote:
>"Al Dykes" <adykes@panix.com> wrote in message
>news:gupbc9$m9r$1@panix5.panix.com...
>> There are some very inpressive flywheel motor-generator units that
>> bridge the many seconds it can take for a generator to pick up the
>> load. ISTR seeing a system with a huge flywheel MG and 3 generators
>> and no batteries. When the power failed, all three generators were
>> told to start.
>
>I once worked with a General Electric Model 312 process control
>computer. Three-phase power supplied the motor that turned the
>32K-word drum memory. One option, not found on the 312 I worked
>with, was a motor/generator hooked to the other end of the drum and a
>large battery bank. The three-phase motor turned the drum and the
>motor/generator charged the batteries. If the three-phase power
>failed, the motor/generator continued to turn the drum, powered by
>the batteries. The computer timing was obtained from one track on
>the drum. Thus as the batteries were depleted, the computer
>continued to operate but just ran a little slower. I thought it was
>a unique design.
Back in the day, all IBM mainframes of the larger sizes had rotating
MG units by default. I dunno if it could be opted-out if the customer
has a UPS system. The smaller midrange IBM machines I had hands-on
experience with didn't have a mg [and] never needed power conditioning
(360/50 and smaller 370.)
When ReallyBigBank in NYC, a maximum IBM shop, got it's first 2040 and
me, with it, circa fall 1975 it was installed in a business operation,
not a power-conditioned datacenter. Starting in the spring of the
next year the 2040 started crashing at about 7:30AM *every day*. DEC
engineers said the machine was not at fault.
After lots of escalation on the physical plant side, we met with the
Consolidated Edison (the power utility) people and they declared, "But
Of Course!" It turns out that ConEd switches daytime power factor
mode for the summer every AM and causes a glitch that apparently every
other brand of computer could handle.
It wasn't my fault. All the planning was done before I joined the
company and I was kind of new to physical plant issues. I learned a
lot.
We got a ferroresonant constant voltage transformer large enough to
need a forklift move. It smoothed everything out, so to speak.
--
Al Dykes
News is something someone wants to suppress, everything else is advertising.
- Lord Northcliffe, publisher of the Daily Mail
***** Moderator's Note *****
What little I know of power factor (trust me, it _is_ little) leads me
to be surprised that it could be adjusted in advance. Please tell us
how this is done, and why it would have to be changed at different
times of the year.
Bill Horne
Temporary Moderator
------------------------------
Date: Mon, 18 May 2009 21:04:31 +0000 (UTC)
From: David Lesher <wb8foz@panix.com>
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Verizon selling off phone lines
Message-ID: <gusigv$mrh$1@reader1.panix.com>
David Clayton <dcstar@myrealbox.com> writes:
> Do US telcos get any "freebie" use of public space for their
> infrastructure, or do they have to pay market rates (like land for
> their COs)?
Buildings they own; but in MD, they get a free ride on property taxes.
The easements for outside plant are a different matter. AFAIK, they
get such free. Fred Goldstein would know the details.
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
------------------------------
Date: 18 May 2009 20:47:54 -0400
From: adykes@panix.com (Al Dykes)
To: redacted@invalid.telecom.csail.mit.edu
Subject: Re: Verizon selling off phone lines
Message-ID: <gusvjq$cta$1@panix5.panix.com>
In article <gusigv$mrh$1@reader1.panix.com>,
David Lesher <wb8foz@panix.com> wrote:
>David Clayton <dcstar@myrealbox.com> writes:
>
>> Do US telcos get any "freebie" use of public space for their
>> infrastructure, or do they have to pay market rates (like land for
>> their COs)?
>
>Buildings they own; but in MD, they get a free ride on property taxes.
>
>The easements for outside plant are a different matter. AFAIK, they
>get such free. Fred Goldstein would know the details.
In NYC, rights to use under-street ducting is franchised to major
electrical contractors in big chunks of area. If my private company
wants to run fibre between two buildings under or via a city street,
all it takes is money, but it has to be done by the franchise owner or
his subcontractors.
There are some under-used tunnels in Manhattan and nobody ever ran a
unofficial wire through any of them. <ahem>
--
Al Dykes
News is something someone wants to suppress, everything else is advertising.
- Lord Northcliffe, publisher of the Daily Mail
------------------------------
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