
From telecom-request@delta.eecs.nwu.edu  Fri Sep 29 20:16:32 1995
by
1995
20:16:32 -0400
telecomlist-outbound; Fri, 29 Sep 1995 16:21:25 -0500
1995
16:21:22 -0500
To: telecom@eecs.nwu.edu


TELECOM Digest     Fri, 29 Sep 95 16:21:00 CDT    Volume 15 : Issue 412

Inside This Issue:                           Editor: Patrick A. Townson

    Re: Lots of Goofups This Week (Brent E. Boyko)
    Re: Lots of Goofups This Week (danny burstein)
    Re: Lots of Goofups This Week (James E. Bellaire)
    Re: Lots of Goofups This Week (Bill Blackwell)
    Re: Will NA Caller ID Boxes Work in Europe? (Jeremy Rogers)
    Re: Will NA Caller ID Boxes Work in Europe? (Pat Barron)
    Re: Variable Length Phone Numbers (John Levine)
    Re: Variable Length Phone Numbers (Martin Kealey)
    Re: Variable Length Phone Numbers (Christian Weisgerber)
    Re: Dialing 911 Instead of Police's 7D Number (Nevin Liber)
    Re: Dialing 911 Instead of Police's 7D Number (Mike Morris)
    Unabomber Full Text Now in Archives (TELECOM Digest Editor)

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
public service systems and networks including Compuserve and America
On Line. It is also gatewayed to Usenet where it appears as the 
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newsgroup 'comp.dcom.telecom'. 

Subscriptions are available to qualified organizations and individual
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The Digest is edited, published and compilation-copyrighted by Patrick
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----------------------------------------------------------------------



In article <telecom15.410.9@eecs.nwu.edu>, TELECOM Digest Editor
<telecom@eecs.nwu.edu> wrote:

> The other major screw-up involved pagers. Did yours go off this week?
> Apparently someone in Houston sent a signal to a satellite (?) which
> in turn caused several satellite receivers to shut down. Does anyone
> have further details on this?

Our Pagenet pagers were out of service from about 11:30 P.M. Tuesday 
night
to 11:30 A.M. Wednesday. The medical staff were not pleased.

According to an Associated Press news article today, a technician at
Space Com, the satellite carrier, accidentally disabled "thousands" of
satellite receivers. Apparently the receivers had to be restored
individually.  The story indicates that five of the national paging
companies use Space Com.

I believe that the individual receivers that they are talking about 
would
include one at each paging transmitter.


Brent E. Boyko  Telecom Engineer
Loma Linda University Medical Center
bboyko@brent.llu.edu

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



In comp.dcom.telecom you write:

> The other major screw-up involved pagers. Did yours go off this week?
> Apparently someone in Houston sent a signal to a satellite (?) which
> in turn caused several satellite receivers to shut down. Does anyone
> have further details on this?

> Per RISKS Digest, one of the carriers for satellite relay sent out a 
> signal which shut down the base receivers in umptity umptity cities.

Huh?

When you send a page the signal gets relayed to <large number> of local 
sites which then feed it into local transmitters. WHile this is designed 
for the (semi) nationwide coverage, it's often the way your neighborhood 
paging system works as well. 

Your "satellite pager" does -not- get its signal directly from orbit, 
but 
rather via a terrestrial relay.

So they shut down the local receivers by remote control. Problem was 
they 
couldn't restart them the same way. 

This could be due to two reasons:

a) There was a complete shutdown so the receivers didn't get the 'turn 
on' signal (after all, they were off....)

b) Pager transmitters are designed so that a group of them spaced, 
perhaps, ten miles apart, all go off simultaneously. Although it flies 
in 
the face of everything I know about radio, they can, and do, set off 
multiple transmitters to ensure (usually) that the signal covers the 
wanted area.

This requires "ultra precise" synchronization. It's quite possible they 
were able to turn the units back on, but did not have remote-synch 
capability.

Mark> A SpaceCom technician at their uplink facility in Tulsa,
Mark> Oklahoma accidentally send out a spacey command shutting down
Mark> the satellite receivers used by pager systems throughout the
Mark> country, affecting millions of pagers.  SpaceCom supports 5 of

I can picture the guy.  He's waiting for the 'Index restructured'
response, when suddenly the screen starts filling with these:

Message from Chicago2: Shutdown completed.
Message from NewYork4: Shutdown completed.
Message from LosAngeles1: Shutdown completed.
Message from Miami3: Shutdown completed.
Message from NewYork2: Shutdown completed.
etc.

Magnus.

dannyb@panix.com (or dburstein@mcimail.com)

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



In TD410 Patrick Townson wrote about this weeks goofs:

You want to know about goof ups?  Someone in the sales department at
my internet provider took an order to change MY email domain over to
uucp (from my current shell/SLIP arrangement).

I noticed that TD was not coming at all since Saturday and sent some
mail to myself which eventually returned via DAEMON.

It is likely that you (Pat) have a box full of DAEMON's from me.  For
that I apologize.  I have firmly instructed my provider not to do this
to you again.

Fortunately lcs.mit.edu has provided me with ftp back issues.  Otherwise 
I
would have starved from lack of Telecom information.

BTW:  Other than this my provider is an excellent and affordable 
service.


James E. Bellaire (JEB6) bellaire@tk.com
                   ^^^^  The ruler of this domain!


[TELECOM Digest Editor's Note: I saw a few of those daemons sent by your
provider but ignored them. Do you think your provider will listen to
and abide by your 'firm instructions'?   <grin>  Just a reminder to all
readers that back issues -- fourteen year's worth, thousands of issues --
can be obtained from the Telecom Archives as needed at lcs.mit.edu using
anonymous FTP.  PAT]

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



According to the Houston Chronicle (_The Paper_(tm)), the shut-downs
were caused when a data entry clerk mistakenly forgot to enter a 
carriage
return when he was entering in the receiver codes into several paging
companies' satellite uplink ...


Bill Blackwell      
bear@electrotex.com 
Houston, Texas, USA 

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



In article 8@eecs.nwu.edu,  <cook4ald@mechanus.magic.ca> writes:

> My friend's family (in Poland) were watching a local TV program that
> mentioned the fact that calling line id was available in the area
> (Warsaw).  They would like to know if the calling id boxes that we can
> buy here (I'm in the Toronto, Ontario, Canada area) would work if they
> were sent there?

I don't know about Poland, but NA CLID equipment won't work on BT in
the UK.


Jez

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



> [TELECOM Digest Editor's Note: What caller-ID boxes do you know that 
run
> on AC rather than battery?  I have never heard of this.   PAT]

My FANS CallScreener plugs into the wall; does not use a battery.


Pat

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



> there is a virtual network in NANP, which can be navigated by taking
> groups of three digits at a time ...

Not really. Consider area code 809, where you need to decode 809 and
the following three digits to tell what country the call is going to.

>  By the way, are land-line numbers portable in NANP yet? ]

In a few cities. There's still three competing technical schemes for
how portability will work, and no agreement at all on who's going to
pay for it.

> As I understand it, the reason that NANP needed to switch to NXX
> area codes was not because it had run out of numbers, but because it
> had run out of prefixes.  If there hadn't been the rigidity that
> prefixes and area codes be exactly three digits, maybe this would have
> been alleviated.

They'd have had to design things quite differently in the first place;
by the time they started to run out, there weren't 10 contiguous area
codes to allocate any more. The NANP worked great for several decades.
It ran into trouble because a lot of things started to need phone
numbers that nobody'd forseen in the late 1940s, e.g. mobile phones,
pagers, modems, faxes, and individual extensions in a company PBX.

> With the price of connectivity coming down, it is not unreasonable to
> consider that proxy lookup services would be at least a reasonable, if
> not better approach, than making each switch do its own database
> lookup?  Indeed, isn't this how 800 number lookup already works?  The
> local switch sees "1800" and then knows "collect 7 more digits and
> refer them to Bellcore" (or whoever).  THEN a decision on routing the
> CALL is made.

That's right. It's also the most likely scenario for local number
portability, although it's still possible that they'll use a scheme
that assigns each prefix to a switch (the same as now) and effectively
call-forwards calls that aren't homed in that switch.

> If compelled signalling were used,

Ah, but it's not. And that's the issue, isn't it?


Regards,

John R. Levine, Trumansburg NY
Primary perpetrator of "The Internet for Dummies"
and Information Superhighwayman wanna-be

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



I really must stop doing this thing of answering multiple points in one
article - but never mind for now.

[1]

>> virtual network in NANP ... groups of three digits at a time ...

> Consider area code 809

It still goegraphically reduces to "the Carribean & misc other bits" -
maybe not a great increase in specificity, but still a reduction to a
nameable geographic entity.  Many area codes are a lot more specific.

I'm not claiming that this is a perfect mental model, but it's at least
somewhat useful, else there wouldn't be people who learn off all the 
area
codes "for fun" because there wouldn't be any point to learning them.

[2]

>> If compelled signalling were used,

> Ah, but it's not. And that's the issue, isn't it?

Quite true; the point I'm trying to get at is that compelled
signalling doesn't necessarily mean opening a voice-grade path all the
way to the far end, so while it's not entirely without cost, that cost
is pretty insignificant; for example, far less than the voice-grade
path used to signal ring-back in a lot of networks.  (It is
conceivable that there may even be a net benefit from cost reductions
elsewhere.)

Sending one keypad digit takes only 4 bits; even if it were to get say
512 bits of framing overhead added, that still only amounts to about 4
ms of voice time - or a fraction of a cent for the entire phone
number, to even the most distant part of the world.


Cheers,

Martin D Kealey  36.88888S/174.72116E   ## Science Fiction Modellers' 
Club of
<martin@kurahaupo.gen.nz>               ## New Zealand     
<info@sfmc.org.nz>
voice +64-9-8150460  fax +64-9-8150529  ## all SF catered for; email for 
info

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



Tony Harminc <EL406045@BROWNVM.BROWN.EDU> writes:

>> What is a phone number? For the most part, a phone number is a 
*route*
>> through the network.

> This is absolutely not true in North America.

Well, AFAIK you can roughly tell the location of +1-xxx-yyy-zzzz if you
know xxx and yyy. (With the obvious exception of 1-800 and other kinds
of portable numbers.)

> Each switch in the network is capable of doing a database lookup on
> (typically) six digits of the phone number to determine the action to
> take to advance the call. The individual digits of the number in no


                                               

> way specify the route the call is to take through the network; this is
> a decision made by each switch as needed, and is based on much more
> than the digits in the number. Currently available trunks, congestion,
> previous routing history, and many other factors can be taken into
> consideration to make routing decisions.

You have to realize that the routing example I gave was simplified a
lot, partly to show my point, partly because I'm not all that familiar
with the details of SS7 routing. Of course a switch can sit there and
collect further digits before making a routing decision, and routing in
Germany is also influenced by trunk availability, congestion, and many
other factors. I think you try to point out differences that don't
exist.

[ my example deleted ]
> Easy yes -- but a disaster for planning and orderly growth.

Why so? I don't have a history of the development of the German
numbering plan and I am too young to remember much of it, but growth
works nicely by expanding into formerly unused portions of the numbering
plan. If a dead end should really come up somewhere, the situation can
be relieved by inserting a single digit somewhere, which is certainly no
worse than North American area code splitting.

The latest major event was the integration of the former East German
network, +37.<area code>.<number> as +49.3<area code>.<number>. No
sweat, since the 3* area code range had wisely been reserved...

> This sort of design ensures that Germany will not have portable
> numbers for a long time.

Germany has had toll free, special service, and other kinds of portable
numbers for several years by now. Their prefixes lead to one of several
centralized switches that perform a data base lookup, negotiate some
billing details with the originating and true destination switch, and
return the true number to place the call to.

Basically, this scheme could be extended to all numbers but I'm not
aware of any plans to do this. As long as the call charges are dependant
on the distance, a principle that doesn't seem to be going out of
fashion anytime soon, a mapping of area code and location remains
desirable.

> Okay -- you are in Germany and you start to dial +1 40 ...
> Now with your scheme, the local switch would have to pick up a trunk 
to
> somewhere -- to where ?

Why should it have to pick up a trunk yet? You miss the point of a SS7
signaling network, where all the switches are connected by what amounts
to a packet-switched network independant of the voice circuits. A trunk
isn't selected until the destination switch has signalled back.

> It isn't even known what country you are calling yet! Then you dial 3
> as the next digit, and the switch in Germany knows you are calling
> Canada rather than the USA. But Germany has trunks to at least two
> points in the area covered by area code 403 - which one should it pick
> up? The next digit is 9, but still nothing is known - it could be
> somewhere near Calgary, or over a thousand miles north in the 
Northwest
> Territories. Only after two more digits (say 79) is it finally known
> what local area the called line is in.

When I dial '+...' ("00..." in Germany) my switch forwards further
digits to one of several switches responsible for handling
international destinations. The default one from here is in
Frankfurt/M. When I dial +1.40 all that happens is some signaling
traffic. Now, when I dial +1.444 I at once get an intercept.
Obviously, there's a lookup that checks for valid North American area
codes. Apart from this, the switch in Frankfurt just sits there and
collects digits until a 10-digit North American number is completed.
Then it makes a routing decision and actually sets up the call.


Christian 'naddy' Weisgerber    naddy@mips.pfalz.de

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



In article <telecom15.409.8@eecs.nwu.edu>, gordon@sneaky.lonestar.org
(Gordon Burditt) wrote:

> Please educate the *POLICE* that 9-1-1 is for life threatening 
> emergencies ONLY.

Good luck.  It seems that if you don't phone it in on 911, they just 
don't
seem to care.

A couple of years ago I was the victim of a hit and run by a drunk 
driver
in Chicago.  Since no one was injured, I phoned it in on the non-
emergency
line.  When I finally got through, they told me since no one was hurt,
they couldn't be bothered to come out to the scene.  If I wanted, I 
could
come down to the station and make a statement.  Luckily, my automobile 
was
still driveable, and I did so.  They reluctantly (kept telling me it
probably wouldn't do any good, etc.) wrote down the information about 
the
accident.  I bet that I would have gotten better treatment if I had just
called 911 in the first place.

Do they record non-emergency calls to the police, fire department, etc.? 
Maybe they ought to start ...


Nevin ":-)" Liber       nevin@CS.Arizona.EDU    (520) 293-2799

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



wes.leatherock@hotelcal.com (Wes Leatherock) writes:

> Martin McCormick <martin@dc.cis.okstate.edu> wrote:

>> The alarm boxes vanished from streets in Tulsa and Oklahoma
>> City as well as many other places as soon as 911 became the method of
>> choice to report emergencies.  I also remember that many of the 
street
>> boxes had a glass window that one had to break with an attached 
hammer
>> to activate the alarm.  This always seemed dumb and dangerous to me,
>> but I am sure there was a good reason for it.

> I believe the idea of the glass window and hammer was to
> reduce the number of false alarms; you had to do something more than
> just walk by and pull the lever.  This was true in most cities I'm
> familiar with.

I spent one summer working for an alarm company and was fortunate
enough to spend some time with the head technician, who was kind
enough to "walk" me through a sample of each kind of alarm system.
The street boxe (and some of the older building alarm) circuits 
use a technology called a McCullogh (Mccullock? McCulloch? sp? I never
saw is written - just heard it spoken) circuit.  Addresses were 
assigned by breaking tabs off a code wheel in the box, and each of
three positions had five tabs.  The spring mechanism had enough energy 
to turn the wheel at least three revolutions, many times five. 

The "console" was basically a buzzer and a light for each circuit --
when a box was tripped the buzzer/light would be "read" by an
operator, who then looked up the number in a card file. Some panels
had 50 circuits.  The circuit used a higher voltage DC (100-150v) that
is alternately shorted and grounded by the leaf switch that rode the
edge of the code wheel in the box.  The system was designed to provide
a usable signal even if one wire of the pair was open.

He told me the glass was there to keep the bugs, snow, dirt and rain
out of the clockwork/cam/leaf switch mechanism.

This is from a 20 year old memory, so I hope I got it right.

Eric Ewanco <eje@world.std.com> writes:

<snip about reporting a stolen car, and the phone book didn't list
the pots line number for the police where it could be easily found>

> So I called that number and they referred me to another seven digit
> number.  (Apparently I had reached some sort of administrative office
> or something.)  So I dialed that SEVEN DIGIT NUMBER and imagine my
> surprised when I hear, "911, please report your emergency."  What
> ensued was a somewhat tense conversation, because I was understandably
> confused as I stayed on the line and argued that I didn't call 911,
> but a seven digit number.  (In retrospect I probably should have just
> apologized and hung up.  Understandably the dispatcher was a bit curt
> as she explained that I had dialed the seven digit number which
> patched into the 911 system.)

Here in the L.A. area quite a few amateur radio autopatches are set
up to take the phone number and validate it before taking the actual
phone line off hook and dialing it. Many are set up to convert 911
into a 7 or 10 digit number (most use the 7/10-digit version of the
CHP LA dispatch 911 number). There is a classic story in the local
ham radio circles about one of the early cellphone 911 calls to the 
Whittier Police Dept (an L.A. suburb) reporting a traffic accident.
They sent the ambulance to the address shown on the screen: the cell
switch site. Another story has a autopatch user calling 911 and
the police show up at the ham radio repeater site.

In both stories the city name changes with the telling, and I've never
been able to pin down the source of either story. Urban legends.
But the stories point out that 7/10 digit alternatives to 911 are 
useful.

>> Our phone books tell us to use 911 only for emergencies. The local
>> police stations in Chicago on the other hand tell us to use 911 for
>> everything.  Who is correct on this?

> Well, I think that with the shift of emphasis to 911, the organization
> and promotion of seven-digit police numbers has become chaotic through
> neglect. 911 is put on the front page whereas the seven-digit numbers
> are relegated to alphabetical listings in the middle, with no 
indication 
> which ones are for police dispatchers, which ones are administrative,
> which ones are for which communities, and so forth.  The telephone
> pinball I had to put up with in this experience was inexcusable, as
> one number directed me to another and another, or maybe nobody 
answered 
> or whatever.  Part of the fault lies with the police department then,
> I think, for failing to provide a clearly defined and effective
> alternative to 911 for non-emergency numbers.

> Hence it may be no wonder that people are more inclined just to dial
> "911" when they want the police for whatever reason.

> I think the solution is to clearly identify emergency and non-
emergency 
> numbers, and under what circumstances they should be called, and then
> make sure that the people who answer them can direct them correctly.

It's my opinion that the designers of the phone books are a bit to
blame. They should include the 7 (or 10) digit non-emergency number of
the police on the same page as the 911 listing. Pacific Bell uses the
inside of the front cover (both white and yellow pages) to list the
cities that the book serves, and the emergency number (911 in 72 point
type, in red ink), and the nonemergency police and fire numbers for
those cities.

The police are a bit to blame also for the poor design of the system 
that doesn't have a non-emergency number to call 24 hours, and the 
workaround the dispatchers have to use to get around that design
(call 911).

And it would be nice to have a standard non-emergency number: perhaps
912 or 999 could be used?  All the hardware is in for 911, all it would 
take is programming, and public education.


Mike Morris                                
morris@grian.cps.altadena.ca.us
#include <disclaimer.std.h>       I have others, but this works the 
best.
   This message assembled from 100% recycled electrons (and pixels).

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



Thank you to everyone who sent the full text of the Unibomber manifesto
to me. I got several copies, which certainly filled my mailbox in a 
hurry. A copy has been placed in the Telecom Archives for anyone who
wants to read the entire thing. You can use two methods of getting it.
The traditional one, anonymous ftp is available at lcs.mit.edu.  You 
would login anonymous, using your name@site as password. Then you must
'cd telecom-archives/reports'. If you prefer to do it by email, you
can send a request to the Telecom Archives Email Information Service
for automatic handling. The instructions for this are:

Send email to tel-archives@lcs.mit.edu.
The subject line does not matter.

As the text in your message:

REPLY yourname@site
GET unabomber
END

The above will get you several files in email with the complete text
plus the rebuttal messages which appeared here awhile back. I hope
you have time to read it all over the weekend! 

If you don't have the current HELP, INFO and DIRECTORY files for the
Archives, you can order those also by adding those three commands in
your email, prior to the END:

HELP
INFO
DIRECTORY
END

Patrick Townson

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

End of TELECOM Digest V15 #412
******************************

                                                                     
