TELECOM Digest     Wed, 29 Jun 2005 01:00:00 EDT    Volume 24 : Issue 299

Inside This Issue:                             Editor: Patrick A. Townson

    Wheelock Outdoor/Loud Noise Environment Ringer (Mike Riddle)
    VoIP Phone Home? (fiatlux)
    Re: Western Union History (Jim Haynes)
    Re: Western Union History (Wesrock@aol.com)
    Re: Where to Buy a Cellular Phone Jammer? (Joseph)
    Re: Where to Buy a Cellular Phone Jammer? (AES)
    Re: Where to Buy a Cellular Phone Jammer? (Michael D. Sullivan)
    Re: Where to Buy a Cellular Phone Jammer? (Danny Burstein)
    Re: 50 Year Unisys Employee Retires (Tony P.)
    Re: DSL Speed (nmclain@annsgarden.com)

Telecom and VOIP (Voice over Internet Protocol) Digest for the
Internet.  All contents here are copyrighted by Patrick Townson and
the individual writers/correspondents. Articles may be used in other
journals or newsgroups, provided the writer's name and the Digest are
included in the fair use quote.  By using -any name or email address-
included herein for -any- reason other than responding to an article
herein, you agree to pay a hundred dollars to the recipients of the
email.

               ===========================

Addresses herein are not to be added to any mailing list, nor to be
sold or given away without explicit written consent.  Chain letters,
viruses, porn, spam, and miscellaneous junk are definitely unwelcome.

We must fight spam for the same reason we fight crime: not because we
are naive enough to believe that we will ever stamp it out, but because
we do not want the kind of world that results when no one stands
against crime.   Geoffrey Welsh

               ===========================

See the bottom of this issue for subscription and archive details
and the name of our lawyer; other stuff of interest.  

----------------------------------------------------------------------

From: Mike Riddle <nospam@ivgate.omahug.org>
Organization: Solitary, Poor, Nasty, Brutish & Short
Subject: Wheelock Outdoor/Loud Noise Environment Ringer
Date: Tue, 28 Jun 2005 21:10:17 -0500


Recently acquired an old Bell Systems outdoor/loud area ringer made by 
Wheelock. Number "KS-16301" stamped inside. Large cast iron or steel 
case, uses 110VAC for the ringer, signalled by 20Hz, 60Hz, or DC.

Anyone have any source for wiring diagrams/options?

N.B.  Either this or something similar in external appearance was used 
for alert horns at SAC bases -- possible still in use at ACC bomber 
installations.

Thanks,

Mike Riddle
mriddle%nospam@ivgate.omahug.org
"To Reply Remove the Obvious"
http://www.mikeriddle.com

------------------------------

From: fiatlux <jmc@canon.org>
Subject: VoIP Phone Home?
Date: 28 Jun 2005 11:11:12 -0700


Written by: Jason Canon
Peach ePublishing LLC

VoIP Phone Home?

The movie Extra Terrestrial (ET) coined the phrase "phone home" and
each year American's look for more cost effective ways to do just
that.  The past 10 years have seen the development and growing
popularity of Voice over Internet Protocol (VoIP) technologies to
achieve cost savings over the traditional circuit-switched telephone
networks. The two dominate technologies used for VoIP are: (1) the
Session Initiation Protocol (SIP) and (2) Peer-2-Peer (P2P).  For
business and educational institutions SIP VoIP solutions have produced
substantial savings. For home voice users, however, SIP VoIP is still
value challenged.

A typical circuit-switched landline phone costs about $19.95 per month
(plus tax). The good old American landline phone should be graphically
depicted beside the word "reliable" in the dictionary. Not only does
it keep working, even when all electrical power fails, but it can even
provide you with a light to dial with. At $15 dollars per month SIP
VoIP is still value challenged due to the lack of full support for
E9-1-1 emergency services and of course the reliability issues
inherent with using a real time application over a "best effort"
network like today's Internet. Although few VoIP articles still
reference Internet Request For Comments (RFC) 3714 "IAB Concerns
Regarding Congestion Control," the technical challenges associated
with VoIP are widely known. Further, even with the recent dubious
edict by the Federal Communications Commission (FCC) that VoIP service
providers will provision support for E9-1-1 within 90 days, this still
leaves the reliability issues unresolved. The use of adaptive rate
CODEC's to prevent congestion collapse is a swell idea if it applies
to my neighbor's service but not my own. Using adaptive rate CODEC's
to elicit voluntary user preemption has no appeal in the modern world.
Technology is supposed to be getting better and it is clearly not
better that users receive disconnects or degraded service quality in
order to constrain network bandwidth consumption.

Quality of Service (QoS) has been the four letter word of the Internet
for a very long time. Yet, we know that real time applications such as
video and voice are a mismatch for "best effort" service models.  Cost
savings are important, but not if they require users to accept
backward technology leaps. After 9/11 the United States should have
begun standardization efforts to insure that VoIP QoS levels would be
equivalent to circuit-switched networks, especially where emergency
E9-1-1 calls are concerned. The recent FCC order only requires that
E9-1-1 call center traffic be properly routed. It does nothing to
insure QoS of the connection once the call is completed.

As for SIP VoIP in the home, there is too little incentive for savvy
consumers to part with more of their hard earned communications
dollars for an industry offering that simply does not meet the needs
of the user. Until something concrete can be done to move SIP VoIP
forward, service based on P2P such as Skype seems to be the only
sensible choice on the kitchen table. Why should home users pay $15 or
more per month for less reliable communications than they already have
with their land line? Skype gives users the ability to experience
"best effort" voice over the Internet for FREE. Could this be the
reason why more than 125 million copies of Skype's P2P software has
been downloaded?  And for the occasions where interconnection with the
existing circuit-switched telephone networks is required, Skype offers
a very competitive 2 cents per minute interconnection rate. With Skype
you can talk for 12 =BD hours interconnected to the phone system for
the same cost as a basic rate SIP VoIP service.

Until genuine changes are made to support SIP VoIP QoS there does not
appear to be a convincing or compelling reason today for users to
choose anything other than P2P VoIP services such as Skype to render
Internet "best effort" home phone services.

You can read the complete article and view associated graphics online
at: http://canon.org/VoIP_Phone_Home.html.

Copyright 2005 Peach ePublishing, LLC

Jason Canon has authored numerous technical research papers including:
photonic switching, gigabit networking, VoIP E9-1-1 and others. He is
an expert author for EzineArticles.com. E-mail: Jason Canon at
jmc@canon.org.

NOTE: For more telecom/internet/networking/computer news from the
daily media, check out our feature 'Telecom Digest Extra' each day at
http://telecom-digest.org/td-extra/more-news.html . Hundreds of new
articles daily.

------------------------------

Subject: Re: Western Union History
Reply-To: jhaynes@alumni.uark.edu
Organization: University of Arkansas Alumni
From: haynes@alumni.uark.edu (Jim Haynes)
Date: Tue, 28 Jun 2005 19:28:11 GMT


In article <telecom24.296.7@telecom-digest.org>,
 <hancock4@bbs.cpcn.com> wrote:

> [Other perspectives welcome.  public replies please]


I composed the following a few days ago and was going to take it to
private email, which bounced.  So here it is.

Oslin also repeats the Western Union article-of-faith that the Bell
System broke its agreement with W.U. when it began offering TWX
service.  And he accuses the U.S. govt., probably correctly, of
favoritism toward ITT, which had something to do with the merger with
Postal.

One could say that Western Union's goose was cooked when they were
offered the chance to buy the Bell patents and turned it down.  Of
course it was a perfectly reasonable decision for them.  They were in
the long distance communication business, and the early telephone
wouldn't transmit very far.  And it was fair enough at that stage to
say the telephone was a curiosity rather than a useful business
machine.  Further they had the operational view that people brought
them telegrams and their operators transmitted them and they delivered
them.  It was hard for them to understand that customers might wish to
speak directly to each other (in an age when people of good breeding
sent handwritten notes to invite their friends to meet with them, and
to reply to such invitations).

Their goose was cooked because the telephone was destined to outgrow
the telegraph in bandwidth and distance, and would have the advantage
of economy of scale.

A second opportunity was lost when the government forced AT&T to
divest its controlling interest in W.U.  Without that we might have
had a coherent national system of voice and record communication,
instead of forcing the two so use separate plant facilities and
compete with each other.  Seems like Postal was the main beneficiary
of that action, since it could not have competed effectively with the
AT&T-WU combine.

I presume AT&T didn't "really" violate any agreement with W.U. when it
introduced TWX.  Otherwise W.U. could have sued an won.  W.U. could
have started a competing service at that time, but they lacked the
local loops it would have required, and would have had to put in their
own or lease from Bell.  Or maybe they considered it and found they
couldn't make it pay.  (Bell getting local loops for TWX at the
marginal cost of loops for telephony; while W.U. would have had to
construct them from scratch.)

Following the tenure of Newcomb Carlton, Vail's hand-picked successor
at W.U., the company seems to have gone through a long period of
lackluster leadership.  One who is more interested in business than I
could see who were the directors at the time and perhaps what their
motives were.

Seems like I read somewhere that W.U. was once offered the opportunity
to buy Teletype and turned it down.  They didn't want to be in the
manufacturing business.

The merger with Postal is portrayed as being both government mandated
and as being on terms very costly to W.U.  If this is true then it is
another instance of the government hobbling a company that was not in
very good shape to begin with.  W.U. did get some good people out of
Postal -- their president W. P. Marshall and engineer Gilbert Vernam
are two I can think of.

W.U. got into the microwave business, which provided a lot more
bandwidth than they needed.  For whatever reason they were not able to
sell their excess bandwidth to the TV networks.  Maybe they didn't
have the capital to serve the places the networks wanted to go; and
again AT&T had the economy of scale to their advantage.  W.U. could
have done what MCI later did, selling bandwidth in competition with
AT&T on high-traffic routes.  AT&T put MCI through a bruising legal
fight on that one, and maybe W.U. didn't have the stomach for it.  And
then W.U. was a member of the club of common carriers, while MCI was
an outsider trying to get in.

The government forced W.U. to divest their cable business.

Then W.U. brought Telex to the U.S.  This seems like a major mistake
to me.  It put them into head-to-head competition with TWX, and AT&T
owned all the local loops.  They couldn't profit from the ability of
Telex to work internationally because they had been divested of their
cable business.  They had to buy a lot of switching equipment to
establish the service, and it was equipment about to be obsoleted by
electronic switching.  Meanwhile AT&T proceeded to put TWX onto the
voice switched network, where it was just a marginal cost.

W.U. operated a lot of local telegraph offices long after they had
ceased to pay for themselves.  In some cases the FCC required the
company to keep the offices open.  W.U. should have had a plan to
convert them to contract agencies; although the best way to do this
would probably involve having the agencies use TWX.

W.U. spent tons of money developing FAX technology.  Not much ever
came of it.  They had their Desk-Fax machines, which relied on the
model of using dedicated local loops and having customers send
messages to the W.U. office for further transmission rather than
direct to their destinations. Today's fax, very successful, makes use
of technologies that were not available when W.U. was in the business
and of end-to-end connections made possible by the excellence of the
telephone system and by the Carterfone regulatory ruling.

W.U. built the Plan 55 message switching system for the Air Force; but
then after a few years it was replaced by AUTODIN which W.U. also
supplied.  I wonder if the lost a lot of money on Plan 55 because of
the short life of the system and the amount of equipment that was made
surplus.  AUTODIN used computer switching technology and I suspect
they took a bath on that because computers were generally overpriced
and became obsolete in such a short time.  And then there's the matter
of software always turning out to be a lot more costly than expected.

Then W.U. got into the business of remote data processing, but didn't
make a go of it.  I don't know what went wrong there; other companies
succeeded (G.E. Information Services for one).

They introduced a dialup data service where you could choose the
bandwidth at the time you dialed the connection.  This seems like a
goofy thing to me.  Some business machines were only capable of
operating at one particular data rate anyway, so the availability of
other rates at different prices was not useful.  It must have been
very costly to provide a switching system that accomodated variable
bandwidth selection.  (It would be fairly easy to do today now that
transmission is digital; but at the time it was not easy.)

They did other goofy things in the consumer area, such as CandyGrams
and Gift America.  Maybe the failure of those didn't entail much of a
writeoff; I don't know.  And they tried some rather pitiful service
offerings in the voice business.

've always wondered if perhaps W.U. was too New York centric in its
management attitudes.  I know that AT&T had the practice of bringing
in middle managers on temporary duty from the Bell operating
companies.  Thus they kept headquarters aware of what like was like
out in the faraway regions, and took the systemwide perspective back
with them when they returned to their home companies.  I wonder if
W.U. did anything like that with its managers.  Also AT&T had the New
York Telephone Co.  to run the business in the city, whereas W.U. had
its corporate headquarters and its major operating activity in the
same building in the city where it did most of its business, along
with most of its R&D organization.  There may have been a tendency to
overlook the problems out in the hinterlands in favor of those at 60
Hudson St.  That's enuf for now.

jhhaynes at earthlink dot net


[TELECOM Digest Editor's Note: I always thought most of the smaller,
less profitable Western Union offices were run as contract agencies;
the 'agent' (or person who put up the money to pay the rent on the
location, the phone bills and the payroll) was also the person who got
the twelve to eighteen percent commission Western Union paid on
'sent paid' and 'received collect' traffic through the office. WUTCO
did supply the big, bulky, very noisy, each one weighed a ton 
teletypewriter machines for the locations, and the telco circuits to
operate them. The business was usually marginal enough that the agent
would pay his clerks minimum wage and stay financially alive by
locating his office around other 24/7 facilities such as bus stations
and train depots. _If_ the agency started making any _real_ profit
as evidenced by the monthly reports the agent had to submit to the
company, then WUTCO would yank the agency back and turn it into a
corporate location, although usually retaining the agent and his
employees as WUTCO employees instead. I know Greyhound Bus has done
that since its beginning: _if_ there is any money to be made, then we
will make it; if not, then _you_ run it as an agency location, living
off the 12-15 percent commission we agreed to pay you along with 
whatever sundries and other items you sell there on your own, assuming
_we_ approved of that part as well.  PAT] 

------------------------------

From: Wesrock@aol.com
Date: Tue, 28 Jun 2005 14:02:21 EDT
Subject: Re: Western Union History


In a message dated 27 Jun 2005 09:55:40 -0700, hancock4@bbs.cpcn.com
writes:

> But I don't understand how WU missed the explosion of computers.  It
> had a microwave system in place.  It even put up a satellite.  I think
> it could've been a long distance carrier, perhaps a niche player, but
> a carrier just the same -- with a good name.

They were a long distance carrier at one time, complete with 10XXX
code.  I used them a time or two, and I believe I knew of a business
that was pic'ed to them, probably through a reseller.

Wes Leatherock
wesrock@aol.com
wleathus@yahoo.com

------------------------------

From: Joseph <JoeOfSeattle@yahoo.com>
Subject: Re: Where to Buy a Cellular Phone Jammer?
Date: Tue, 28 Jun 2005 17:22:12 -0700
Reply-To: JoeOfSeattle@yahoo.com


On Tue, 28 Jun 2005 05:11:46 GMT, Dale Farmer <dale@cybercom.net>
wrote:

> Except it doesn't work.  Better to put scanners up and listen to their
> transmissions.

Which with digital encryption will be a mighty task!

------------------------------

From: AES <siegman@stanford.edu>
Subject: Re: Where to Buy a Cellular Phone Jammer?
Date: Tue, 28 Jun 2005 19:34:08 -0700
Organization: Stanford University


In article <telecom24.298.7@telecom-digest.org>, Dale Farmer
<dale@cybercom.net> wrote:

>> So what legitimate reasons are there to use a cell phone jammer? (Note
>> that I said legitimate, not legal.)

Maybe built into an auto, just enough signal strength to be effective
inside the auto, comes on when the ignition is turned on and the
gearshift is anywhere but Park?

(with maybe a DISABLE button accessible only from the back seat, which
has to be held in continuously to keep the jammer off)

I'm not seriously proposing this, just noting that some might think it
a legitimate safety requirement.

------------------------------

From: Michael D. Sullivan <userid@camsul.example.invalid>
Subject: Re: Where to Buy a Cellular Phone Jammer?
Date: Wed, 29 Jun 2005 02:43:02 GMT


Fred Atkinson wrote:

> On Sun, 26 Jun 2005 23:21:42 -0400, mc <mc_no_spam@uga.edu> wrote:
 
>> Not as far as I know.  The Communications Act of 1934 gets amended
>> all the time, but it is still, as far as I know, the basis of radio
>> regulation in this country (and, yes, television and cell phones
>> are, physically, radio).  Did it go away when I wasn't looking?

> Well, the Telecommunications Act of 1996 was enacted.  I had assumed
> that it replaced the Communications Act of 1934.  I guess I was wrong
> on that assumption.  Do we have any lawyers on here that can clarify
> that issue?

No, the 1996 Telecom Act did not replace the Communications Act of
1934; it amended some sections of it and added some new sections to
it.  I am a wireless telecom lawyer in a Washington, D.C. firm, and
those are facts, not legal opinions.

As to jammers, they are completely illegal to import, manufacture, or
use in the United States (unless you are an arm of the federal
government or have an experimental license permitting jammer use for
testing purposes -- which would require you not to jam licensed
cellular signals.  In fact, the FCC just reissued a public notice to
that effect.

 Entitled, "Sale or Use of Transmitters Designed to Prevent, Jam or
Interfere with Cell Phone Communications is Prohibited in the United
States," Document # DA-05-1776, and dated June 27, 2005, it's
available at
<http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-05-1776A1.pdf>.

Here's the text:

[FCC Public Notice Letterhead]
                                                               DA-05-1776
                                                            June 27, 2005

  Sale or Use of Transmitters Designed to Prevent, Jam or Interfere with
       Cell Phone Communications is Prohibited in the United States

In response to multiple inquiries concerning the sale and use of
transmitters designed to prevent, jam or interfere with the operation
of cellular and personal communications service (PCS) telephones, the
Federal Communications Commission (FCC) is issuing this Public Notice
to make clear that the marketing, sale, or operation of this type of
equipment is unlawful. Anyone involved with such activities may be
subject to forfeitures, fines or even criminal prosecution.

Cellular and PCS telephones provide valuable wireless communications
services to the American public for business and personal
communications. Recently, however, the FCC has seen a growing interest
in devices -- called 'cellular jammers' or 'cell phone jammers' --
designed to deliberately jam or disrupt wireless communications.

Inquiries about the use of cellular jammers are often accompanied by
comments that the use of wireless phones in public places is
disruptive and annoying. Advertisements for cellular jammers suggest
that the devices may be used on commuter trains, in theaters, hotels,
restaurants and other locations the public frequents.

The Communications Act of 1934, as amended, and the FCC rules prohibit 
the manufacture, importation, marketing, sale or operation of these 
devices within the United States (See Section 302(b) of the 
Communications Act, 47 USC 302a(b) and Section 2.803(a) of the FCC's 
rules, 47 CFR 2.803(a)). In addition, it is unlawful for any person to 
willfully or maliciously interfere with the radio communications of any 
station licensed or authorized under the Act or operated by the U.S. 
Government (See Section 333 of the Communications Act, 47 USC  333). 
Further, Section 301 of the Act, 47 USC  301, requires persons 
operating or using radio transmitters to be licensed or authorized under 
the Commission's rules.

Parties violating the provisions of the Communications Act and/or FCC
rules mentioned above may be subject to the penalties set forth in 47
USC 501-510. Monetary forfeitures for a first offense can be
as much as $11,000 a day for each violation and could subject the
offender to criminal prosecution. Equipment may also be seized by the
United States Marshals and forfeited to the U.S. Government.

For additional information, contact Brian Butler, Spectrum Enforcement
Division, Enforcement Bureau, at (202) 418-1160 or
brian.butler@fcc.gov.

By the Enforcement Bureau, Office of Engineering and Technology, and 
Wireless Telecommunications Bureau.

             =============================

As the Public Notice says, if you have any questions, call the FCC's
spectrum cop, Brian Butler.  He's the dedicated spokesperson on this
issue for the Enforcement and Wireless bureaus as well as the Office
of Engineering and Technology.  Personally, I don't see much ambiguity
in what the FCC said.  Jammers are illegal.  Period.


Michael D. Sullivan
Bethesda, MD (USA)
(Replace "example.invalid" with "com" in my address.)

------------------------------

From: dannyb@panix.com (danny burstein)
Subject: Re: Where to Buy a Cellular Phone Jammer?
Date: 28 Jun 2005 15:23:25 -0400


In <telecom24.298.7@telecom-digest.org> Dale Farmer
<dale@cybercom.net> writes:

>> So what legitimate reasons are there to use a cell phone jammer? (Note
>> that I said legitimate, not legal.)

> The only reason I can think of offhand is for a bomb squad to use to
> block one possible source of remote detonation.  I started to type
> that a hostage situation would also be one, but then it occurred to me
> that there may be non-hostage innocents trapped in there as well, who
> might want to call the police for assistance in escaping. 

The various hostage rescue groups have access to cellular blockers, as
well as contact numbers at the cellcos, to do various degrees of
restricting cellular usage. The main reason is to prevent the hostage
takers from being able to talk to other folk, but there are plenty of
secondary ones as well.

Oh, and when they _really_ need to block cellular communications, they
have been known to physically shut down the local cell towers.

_____________________________________________________
Knowledge may be power, but communications is the key
		     dannyb@panix.com 
[to foil spammers, my address has been double rot-13 encoded]

------------------------------

From: Tony P. <kd1s@nospamplease.cox.reallynospam.net>
Subject: Re: 50 Year Unisys Employee Retires
Organization: ATCC
Date: Tue, 28 Jun 2005 20:36:48 -0400


In article <telecom24.297.4@telecom-digest.org>, hancock4@bbs.cpcn.com 
says:

> The Philadelphia Inquirer did a feature article on a man, age 68, who
> was retiring from Unisys after 50 years of service.  (He started with
> Unisys precedessor Burroughs).

> It's extremely rare today for someone to work 50 years for the same
> corporation.  In 1986 Unisys had 123,000 employees, now it has 36,400.
> Only 15% of Americans 65 and over are still working and the average
> person retiring today has been with his employer 10 years, not 50.

I'm a state employee. Our legislature just handed us a bon mot that says 
most of us won't be able to retire until 70, and at that we won't get 
the same benefit as those before us. 

It's funny -- our director of finance is retiring end of this year. We
were joking about it. I said she should be happy that we're financing
her retirement. My boss said she should invite us over for the dinner
we paid for. It was too funny but demonstrated that retirement systems
are in fact Ponzi Schemes.

> [TELECOM Digest Editor's Note: One important reason companies do not
> keep around 40-50 year employees any longer is because that employee's
> benefits package is usually so extravagant. For example, I recall one
> fellow who had worked for Standard Oil more than twenty years back in
> the 1960's, when I was there.  Working there that long, he was
> entitled to five weeks paid vacation every year, and first choice of
> the available times for vacation. He _always_ managed to parlay that
> five week vacation into _six_ weeks by scheduling his vacation times
> around weeks which had holidays in them, which entitled him to an
> extra vacacation day. For example, vacation during the week which
> contained Memorial Day, also the week which contained Independence Day
> and Labor Day got him _three extra days_ right there. So he would then
> take those three extra days vacation and either use them for the
> Monday <-> Wednesday of Thanksgiving Week when the entire office got
> two days (Thursday and Friday) off anyway. Or, depending on how the
> calendar worked out that year, maybe he would take those three days
> during Christmas/New Years week. 

> Needless to say, Standard Oil got quite annoyed at having to legally
> pay him for not being there for large gaps of time. Eventually, they
> had a whole bunch of people in that situation and of course, if you
> can find an excuse for letting the person go, then you also have to
> pay them for the _company's share_ of their 401-K plan or whatever,
> _plus_ their severance pay, _plus_ their pension, etc. And there is
> absolutely no reason a good supervisor cannot find an excuse -- _any_
> lawful excuse will do, to can you if they wish to do so. That is one
> reason most companies do not like to have employees around that long;
> to their way of thinking, the person has gotten just to expensive for
> them. 

Hell, with the comp time I generate I get about 6 weeks a year. U.S.
employers are very stingy about time off. All comes down to that
Calvinist work ethic.



[TELECOM Digest Editor's Note: I think you meant to say the
'Protestant Work Ethic' instead of 'Calvinist'; but anyway, don't
be so harsh with John Calvin. He was an 'okay' guy  <wink>!  PAT]

------------------------------

Date: Tue, 28 Jun 2005 21:10:54 -0600
From: nmclain@annsgarden.com
Subject: Re: DSL Speed


Choreboy <choreboyREMOVE@localnet.com> wrote:

>>> Between the CO and the customer, isn't voice service
>>> just bare wire?

> Neal McLain wrote:

>> Not necessarily.  But let's clarify some terminology first.

>> I assume that:
>>   - By "bare wire" you don't really mean "bare" (as in
>>     uninsulated); you're simply implying that there's nothing in
>>     the wirepair, other than copper conductors, that would affect
>>     the transmission of signals.

> Oops, I was thinking "not coaxial" and "bare" popped into my head.

Actually, it is possible for a local loop to be "bare."  It's called
"open wire" -- bare uninsulated conductors attached to glass or
ceramic insulators supported by crossarms.  Phone companies used
open-wire lines for years.  As recently as 2003, the Union Pacific RR
still had a few open-wire circuits in use.  http://tinyurl.com/dzu5z
(Figures 12-15).

>> Each RT is connected to a host CO, and from the point of view of the
>> customer, it's indistinguishable from the CO.  POTS lines served
>> from the RT are switched at the CO; the RT simply relays signals
>> back and forth between the customer and the CO.  Numbers are part of
>> the same NPA-NXX blocks as the host CO.

> Is it indistinguishable if the customer has a V.90 modem?  I think
> I've read that an RT won't allow 56k dialups.

Some RTs allow V.90 modems; some don't.  Apparently, yours does
(assuming that's the reason the farm can be so far from the CO and
still get DSL).  A good tutorial on this issue is at
http://www.aztek-eng.com/TIA-paper.PDF .

>> Each [digital loop carrier] RT is connected to its host CO by one or
>> more digital circuits.  Depending on the number of POTS lines
>> needed, the digital connection can be as simple as a single T1
>> implemented over two copper wirepairs, or it can be some multiplexed
>> combination of several T1s implemented over coax, fiber, or
>> microwave.  See http://tinyurl.com/9oqru .

> Does an RT entail an extra A/D conversion?

Some do; some don't.  The tutorial cited above describes the
differences.

>> Note that dialup-modem data signals carried in the 300-3000 Hz voice
>> passband are not demodulated at the CO or RT; instead, they are
>> sampled at 8000 sps just like voice or any other audio signal.  This
>> fact imposes an absolute theoretical maximum dial-up data rate of
>> 64Kbps.  As other contributors have noted, it's impossible to attain
>> even that rate in practice due to synchronization errors between the
>> user's modem and the sampling rate.

> A carrier vor V.90 must have some very precise modulation.  It's
> amazing that an 8kHz sampling can capture it well enough to be
> useful.

Frequently it can't, which is why your modem downgrades to a slower
speed.

>> All of these noise sources collectively impair the ability of the loop
>> to carry DSL signals.

> Local loop cables (trunk cables?) seem to deteriorate.  Phone men seem
> to look for available pairs when customers complain of noise.  I
> wonder if voltage from nearby lightning strikes might cause pinhole
> damage to the insulation of twisted pairs, and over the years it gets
> hard to find a good pair.

Nearby lightning strikes likely would do a lot more than cause
"pinhole damage."  But you're right about telco cables deteriorating
over time.  Water intrusion can cause severe interference ("every time
it rains, I get static on my telephone!").

>> LOAD COILS.  The frequency-dependent attenuation characteristics of
>> the loop (as described above) also affect voice band frequencies
>> (300-3000 Hz), resulting in rolloff of the higher frequencies of voice
>> signals.  To solve this problem, telcos have traditionally installed
>> "load coils" at 6000-foot intervals on long (typically >18K feet)
>> loops.  A load coil is a small inductor installed across the
>> conductors to cancel the affects of interconductor capacitance.
>> Although load coils reduce high-frequency rolloff within the voice
>> band, they cause severe attenuation above 4000 Hz.  See
>> http://tinyurl.com/8njv3 .

> At DSL frequencies I would have thought coil impedance would be too
> high to matter.  I don't quite grasp it.

Any other reader want to tackle this question?

> Load coils might be one reason a particular phone sounds distorted at
> a particular location.

I doubt that, but I guess it's possible.

>> In areas where outside plant (OSP) is installed on utility poles,
>> telco drop terminals are called "aerial terminals" or "boots";
>> typically, a terminal is installed at each pole....

> That's what somebody pointed out to me as an inline amp.  If I could
> remember who it was, I'd correct him!

Maybe that somebody was pointing to a cable TV amplifier.  They look
somewhat like aerial terminals, except that cable amps are usually
aluminum rather than black.
http://www.sbe24.org/archive/c24jun98.asp#six Drawings 8 and 9.

>> Each drop terminal has:

>>   - Two cable ports for the distribution cable: input and output.
>>     When a drop terminal is installed, these ports are often
>>     sealed as protection against water intrusion.  These seals
>>     make it virtually impossible to gain access to the individual
>>     wirepairs within the distribution cable.

> As I recall, a phone man appeared to have an aerial terminal open
> after I lost phone service one day.  He said he'd made a mistake and
> would try to figure out how to reconnect me.

Those damn OPS records again!

>>   - Several drop ports, one for each wirepair in the distribution
>>     cable.  These ports are usually implemented with screw
>>     terminals or punchdown blocks.

> Across the street, a small trunk line (cable with lots of wire pairs)
> comes from the aerial terminal down a couple of feet to a fusebox on
> the utility pole.  (I think the telco calls them something besides
> fuses.)  The drop cables come out of that box.

Probably just a junction box.

>> These unterminated wirepairs act like tuned-stub filters.  Since
>> they're unterminated, arriving signals are reflected back; these
>> reflected signals interfere with the primary signals.  In the extreme
>> case -- when the reflected signal is 180 degrees out-of-phase with the
>> primary signal -- the primary signal is severely attenuated.

> Offhand, that sounds like a stub of 1/4 wavelength.  Could the modems
> could mitigate the problem by the frequency they negotiate?

I believe the DSLAM can select both the downstream frequency (that it
uses) and the upstream frequency (that it tells the customer's DSL
modem to use).  Perhaps some other reader can give us a more complete
answer.

>> DSL signals are modulated onto carriers in two bands:
>>         Uplink   (Modem to DSLAM)  30- 110 KHz
>>         Downlink (DSLAM to Modem) 110-1100 KHz

> I wonder how they're modulated.

Can any other reader answer this question?

>> In a previous life, when I worked for a radio station, we sometimes
>> used phone patches for connections to remote locations.  At each end,
>> we'd connect a "phone patch box" directly to the ring-and-tip of a
>> phone line.  Then we'd dial up a connection with a conventional phone,
>> switch in resistors to keep the line open, and hang up the phones.
>> Voice quality wasn't as good as it would have been with a wideband
>> audio circuit, but it was certainly far better than it would have been
>> if we'd used the telephones themselves.  More than adequate for a
>> sports or news report.

> I wonder if the phone patch box had adjustments to flatten the
> frequency response.

I don't think it did, but that was a long time ago.

>> Of course, making a direct electrical connection to a phone line was
>> illegal back in those days (late 50s, early 60s).  But we were on good
>> terms with the phone guys, so they just looked the other way.

> Could you have gone to the federal penitentiary?

AT&T prohibited any direct electrical connections to its network, but
I don't think anybody ever went to jail for violating it -- AFAIK, all
AT&T could do was pull the plug.

> Was there a good reason for the law?

The story of how AT&T was forced to relax its no-connections rule, and
how subsequent events eventually led to AT&T's ultimate (if still
pending) demise, are perennial topics here on TD.

Tom Farley's "Telephone History Series" relates the story in detail at
http://www.privateline.com/TelephoneHistory/History1.htm .  The
direct-connection subplot starts on page 10
http://www.privateline.com/TelephoneHistory4/History4A.htm .

Mike Sandman's website has a history page (intermixed with pitches for
products he's selling) at http://www.sandman.com/telhist.html .  Mike
is a long-time sponsor of TD, so feel free to buy something from him.

>>> Think what would have happened if RG-59 hadn't been invented.
>>> Everybody would have used RG-6, which looks nearly the same but
>>> attenuates uhf much less.  With better reception there would have
>>> been more uhf stations and less demand for cable.

>> As a former cable guy, I don't agree with that.  Many UHF stations
>> depended on cable TV systems to distribute their signals throughout
>> their "specified zones" (which, back in the '60s and '70s, was a
>> 35-mile radius around the city of license).  This was particularly
>> true in mountainous areas where cable T systems carried UHF signals
>> to specified-zone communities that were beyond the reach of their
>> transmitters.

> With a bow-tie antenna, a good UHF amp, a rotator, and RG-6U, we could
> receive so many channels that we weren't interested in cable.

Well, obviously you don't live in a place like Mahanoy City
Pennsylvania, Tuckerman Arkansas, or Astoria Oregon -- places where it
simply isn't possible to get any station -- UHF or VHF -- off the air.
Cable TV started in all three of those communities in 1948, and all
three still claim to have been first.

Neal McLain


[TELECOM Digest Editor's Note: And don't forget Independence, KS where
until cable came along (via Time Warner in the 1980's) our television
reception consisted of TWO channels; channel 6 and channel 9, but only
one of those two if you wanted a good picture. Most people had very
_high_ antennas on their house if they wanted television, and they
compromised by using a 'rotor' attached to their TV set to turn the
rooftop antenna one way or the other. If they could not afford the 
rotor, then they left the antenna turned sort of in the middle and
lived with that. We got one station from Tulsa, Oklahoma (80 miles
almost straight south)  and one station from Joplin, Missouri (90
miles more or less straight east.) Around here, 'big city' (as in
presence of television stations) means Wichita, KS which is 110 miles
northwest, or Topeka KS which is about 150 miles straight north, and
we could not get those stations very well at all in those days. PAT]

------------------------------


TELECOM Digest is an electronic journal devoted mostly but not
exclusively to telecommunications topics. It is circulated anywhere
there is email, in addition to various telecom forums on a variety of
networks such as Compuserve and America On Line, Yahoo Groups, and
other forums.  It is also gatewayed to Usenet where it appears as the
moderated newsgroup 'comp.dcom.telecom'.

TELECOM Digest is a not-for-profit, mostly non-commercial educational
service offered to the Internet by Patrick Townson. All the contents
of the Digest are compilation-copyrighted. You may reprint articles in
some other media on an occasional basis, but please attribute my work
and that of the original author.

Contact information:    Patrick Townson/TELECOM Digest
                        Post Office Box 50
                        Independence, KS 67301
                        Phone: 620-402-0134
                        Fax 1: 775-255-9970
                        Fax 2: 530-309-7234
                        Fax 3: 208-692-5145         
                        Email: editor@telecom-digest.org

Subscribe:  telecom-subscribe@telecom-digest.org
Unsubscribe:telecom-unsubscribe@telecom-digest.org

This Digest is the oldest continuing e-journal about telecomm-
unications on the Internet, having been founded in August, 1981 and
published continuously since then.  Our archives are available for
your review/research. We believe we are the oldest e-zine/mailing list
on the internet in any category!

URL information:        http://telecom-digest.org

Anonymous FTP: mirror.lcs.mit.edu/telecom-archives/archives/
  (or use our mirror site: ftp.epix.net/pub/telecom-archives)

RSS Syndication of TELECOM Digest: http://telecom-digest.org/rss.html
  For syndication examples see http://www.feedrollpro.com/syndicate.php?id=308
    and also http://feeds.feedburner.com/TelecomDigest

*************************************************************************
*   TELECOM Digest is partially funded by a grant from                  *
*   Judith Oppenheimer, President of ICB Inc. and purveyor of accurate  *
*   800 & Dot Com News, Intelligence, Analysis, and Consulting.         *
*   http://ICBTollFree.com, http://1800TheExpert.com                    *
*   Views expressed herein should not be construed as representing      *
*   views of Judith Oppenheimer or ICB Inc.                             *
*************************************************************************

ICB Toll Free News.  Contact information is not sold, rented or leased.

One click a day feeds a person a meal.  Go to http://www.thehungersite.com

Copyright 2004 ICB, Inc. and TELECOM Digest. All rights reserved.
Our attorney is Bill Levant, of Blue Bell, PA.

              ************************

DIRECTORY ASSISTANCE JUST 65 CENTS ONE OR TWO INQUIRIES CHARGED TO
YOUR CREDIT CARD!  REAL TIME, UP TO DATE! SPONSORED BY TELECOM DIGEST
AND EASY411.COM   SIGN UP AT http://www.easy411.com/telecomdigest !

              ************************

Visit http://www.mstm.okstate.edu and take the next step in your
career with a Master of Science in Telecommunications Management
(MSTM) degree from Oklahoma State University (OSU). This 35
credit-hour interdisciplinary program is designed to give you the
skills necessary to manage telecommunications networks, including
data, video, and voice networks.

The MSTM degree draws on the expertise of the OSU's College
of Business Administration; the College of Arts and Sciences; and the
College of Engineering, Architecture and Technology. The program has
state-of-the-art lab facilities on the Stillwater and Tulsa campus
offering hands-on learning to enhance the program curriculum.  Classes
are available in Stillwater, Tulsa, or through distance learning.

Please contact Jay Boyington for additional information at
405-744-9000, mstm-osu@okstate.edu, or visit the MSTM web site at
http://www.mstm.okstate.edu

              ************************

   ---------------------------------------------------------------

Finally, the Digest is funded by gifts from generous readers such as
yourself who provide funding in amounts deemed appropriate. Your help
is important and appreciated. A suggested donation of fifty dollars
per year per reader is considered appropriate. See our address above.
Please make at least a single donation to cover the cost of processing
your name to the mailing list. 

All opinions expressed herein are deemed to be those of the
author. Any organizations listed are for identification purposes only
and messages should not be considered any official expression by the
organization.

End of TELECOM Digest V24 #299
******************************