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TELECOM Digest     Fri, 8 Sep 95 08:06:00 CDT    Volume 15 : Issue 375

Inside This Issue:                          Editor: Patrick A. Townson

    Re: Area Code Crisis -- A Different Viewpoint (Fred R. Goldstein)
    Re: Area Code Crisis -- A Different Viewpoint (Wes Leatherock)
    Re: Area Code Crisis -- A Different Viewpoint (Sam Spens Clason)
    Re: Area Code Crisis -- A Different Viewpoint (Dik Winter)
    UC Berkeley Short Courses on Broadband and Wireless Comm (Harvey 
Stern)
    Variable Length Phone Numbers (Christian Weisgerber)
    Excel Telecommunications Cited For Slamming (DLD Digest via Mike 
Troutman)
    Re: Names For That Key Under the 9 (Mark Brader)
    Re: Names For That Key Under the 9 (Paul O'Nolan)
    Re: Names For That Key Under the 9 (John R. Covert)

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



In article <telecom15.372.9@eecs.nwu.edu>, dmcmahon@edlgu4.ericsson.se 
says...

With regard to variable-length numbers and why they work in Europe and
not in the USA or Canada ...

>> [I don't know, never having been there, but I would expect that even
>> in Germany where DDI numbers can have a variable length inward 
dialing
>> suffix, the PBX would know still when to initiate an immediate
>> connection because this no-prefix policy also applies to extension
>> numbers (eg no ordinary extension numbers start with a 0).  Can 
anyone
>> in +49 confirm or deny this?]

> Not from here, but there are two ways this can work:

> 1) Get a speech path to the PBX and then dial your additional digits;
> or

> 2) Define either fixed (with additional analysis) or variable (with
> timeout) length numbers in *ALL* exchanges where the PBX could be
> called from, and that's a lot op places ...

Neither is the reality.  In practice, the way variable-length numbers
works is based upon the trunk signalling (two l's, British spelling)
method used in Europe, which is different from the trunk signaling
(one l, American spelling) in the USA.  The European networks
(pre-SS7) used compelled signaling (such as MF/R2), in which each
digit is sent on an open trunk down to the next, and ack'd at the far
end.  When the far end has enough digits, it sends the appropriate
signal and the call goes ahead.  This had some obvous round-trip-delay
issues, but was plenty fast for the old steppers that dominated
Europe.  (This is a stepper-friendly scheme.)

The USA, on the other hand, implemented toll dialing in crossbars,
which have digit registers that store dialed digits.  Thus the trunk
isn't selected until a three-digit (or six-digit with NPA) prefix is
dialed, and the dialed number is sent en-bloc once all seven or ten
digits (plus the 1 in some cases, but that wasn't actually part of the
number) are collected.  In the American system, the originating switch
needs to know how many digits will be there.  IDDD time-outs, of
course, are a hack that were added because of this incompatibility.

With SS7 (or ISDN), digits can still be sent en-bloc or "compelled",
as required.


Fred R. Goldstein   k1io    fgoldstein@bbn.com
Bolt Beranek & Newman Inc., Cambridge MA  USA   +1 617 873 3850
Opinions are mine alone; sharing requires permission.

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



martin@kurahaupo.gen.nz (Martin D Kealey) wrote:

       [ ... text deleted ... ]

 > What do you mean here?  There is no NANP calling card format.  I 
think you
 > are talking about LEC calling cards which (usually) mean NPA-NXX-XXXX 
YYYY
 > where YYYY is the PIN.  It has nothing to do with carrier selection; 
in
 > fact, the call will be placed over the carrier that that particular 
phone
is
 > presubscribed to (unless that carier doesn't accept LEC cars - 
unlikely).  

 > Most IXC calling cards are not composed of a particular phone number,
though
 > you can have the card number reflect your home number, since it is 
usually
 > possible to choose the number.

        This varies all over the place.  Some IXCs typically *do*
issue a calling card number that corresponds to your telephone number.
I have had such cards from AT&T, MCI and Sprint, as well as my LEC,
but also some which are non-conforming from the same IXCs.

        Calling cards are consistently used to make calls over carriers
other than the one the calling phone is presubscribed to -- by dialing
10XXX+0+, or by dialing an 800 number.

        Sprint a year or two ago, and may still, have an arrangement
to call using your Discover card.  This is a different 800 number for
this purpose, and you dial your Discover card number (16 digits) as
your calling card number.

        Most carriers do accept calls on LEC cards or in that format,
particularly carriers such as Oncor and other ones which charge
excessive rates, since they have no other way to bill your call except
through your LEC account.  (Surely no one has an Oncor calling
card[!].)


Wes Leatherock   wes.leatherock@hotelcal.com                            
wes.leatherock@oubbs.telecom.uoknor.edu                       
wes.leatherock@f2001.n147.z1.fidonet.org           

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



In <telecom15.372.9@eecs.nwu.edu> dmcmahon@edlgu4.ericsson.se (Denis 
McMahon) 
writes:

> martin@kurahaupo.kurahaupo.gen.nz (Martin D Kealey) wrote:

>> There is something to be said for having all national
>> numbers of a uniform length to avoid other countries having
>> to maintain digit-length tables, but this doesn't constrain
>> length-variability of local numbers.

> OK, but for every country any variable length national
> numbers will invariably mean variable length international
> ones as well. ie in the UK we have a mix of 10 and 11 digit
> national numbers, and that means that +44 can be followed by
> either 9 or 10 digits!!

> This means that for calls to the UK, either the shorter
> number length has to time out, or analysis has to be done at
> the next digit - which is another ten lines of data to
> maintain in every switch worldwide that supports
> international dialing!

In the good old days when calling grandma I'd dial 0175 (area code),
wait for second dialtone and then dial her local number.  Dialing 0175
actually connected me to her area code main exchange from where I then
dialed her local number.  This way my local or area code exchange
needn't know anything about the numbering in 0175.

Today there are some 300 AXE10 local and transport switches in Sweden.
But there are only a few *gateway* switches.  They'd be the only ones
that need to deal with foreing numbering.


Sam   http://www.nada.kth.se/~sam,  sam@nada.kth.se,  +46 701234567

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



Steve Cogorno writes:

> The main problem with variable length phone numbers is NOT technical
> as you have pointed out; it is difficult for humans to use.  It is
> very confusing to not know how many digits to expect.  Suppose you
> have a form that someone has filled out and there are only six digits.
> Does this mean that the number is incomplete, or is it actually
> correct?

As variable length is/was just about the norm in Europe I can attest
that it was not confusing.  In the Netherlands the norm was that the
first digit of the subscriber number told the number of digits.  When
expansion was needed some numbers got an additional first digit, again
based on the original first number.  So the (actual) number in
Amsterdam 59121 was changed to 359121 and later to 6395121.  The
intercept is easy to understand: "The number has been changed, dial
now first the digit 3 followed by the old number".  What is the
intercept after the grace period when you dial a number by its old
area code in the US?

The argument about forms is bogus.  There are many cases where the
number of figures is not fixed in something you can fill out in a
form.  When in the UK something fills in his car registration number
as "V 5", would somebody wonder whether it was incomplete or actually
correct?  (Yes, that number does exist; I have seen it.)  When
somebody fills in his Dutch giro-account as 4832 does this mean the
number is incomplete, or actually correct?  (Again, that number does
exist together with 5, 6 and 7 digit numbers.  Probably also numbers
with less digits.)

Variable length phone numbers appear to be confusing to those not used
to it; that does not mean it is generally confusing!


dik t. winter, cwi, kruislaan 413, 1098 sj  amsterdam, nederland, 
+31205924098
home: bovenover 215, 1025 jn  amsterdam, nederland; e-mail: dik@cwi.nl

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



U.C. Berkeley   Continuing Education in Engineering
Announces 4 Short Courses on Broadband Communications, Wireless Networks

SONET/ATM-BASED BROADBAND NETWORKS: Systems, Architectures and
Designs  (November 29-December1, 1995)

It is widely accepted that future broadband networks will be based on
the SONET (Synchronous Optical Network) standards and the ATM
(Asynchronous transfer Mode) technique.  This course is an in-depth
examination of the fundamental concepts and the implementation issues
for development of future high-speed networks.  Topics include:
Broadband ISDN Transfer Protocol, high speed computer/network
interface (HiPPI), ATM switch architectures, ATM network
congestion/flow control, VLSI designs in SONET/ATM networks.  This
course is intended for engineers who are currently active or
anticipate future involvement in this field.

Lecturer: H. Jonathan Chao, Ph.D., Associate Professor, Brooklyn
Polytechnic University.  Dr. Chao holds more than a dozen patents and
has authored over 40 technical publications in the areas of ATM
switches, high-speed computer communications, and congestion/flow
control in ATM networks.

MODERN TELECOMMUNICATIONS: Wide Area Networks, Personal Communication
Systems, Network Management and Control, and Multimedia Applications
(November 2-3, 1995)

This course is designed as a gentle but comprehensive overview of
telecommunications including current status and future directions.
This course traces the evolution of telecommunications, starting from
its voice roots and progressing through local, metropolitan, and wide
area networks, narrowband ISDN, asynchronous transfer mode, broadband
ISDN, satellite systems, optical communications, cellular radio,
personal communication systems, all-optical networks, and multimedia
services.

Lecturer: Anthony S. Acampora, Ph.D., Professor, Electrical
Engineering, Columbia University.  He is Director, Center for
Telecommunications Research. He became a professor following a 20 year
career at AT&T Bell Laboratories, is an IEEE Fellow, and is a former
member of the IEEE Communications Society Board of Governors.

NETWORKS FOR DIGITAL WIRELESS ACCESS:  Cellular, Voice, Data,
Packet, and Personal Communication Systems (November 8-10, 1995)

This comprehensive course is focused on the principles, technologies,
system architectures, standards, and market forces driving wireless
access.  At the core of this course are the cellular/microcellular/
frequency reuse concepts needed to enable adequate wireless access
capacity for Personal Communication Services (PCS).  Presented are
both the physical-level issues associated with wireless access and the
network-level issues arising from the inherent mobility of the
subscriber. Standards are fully treated including GSM (TDMA), IS-54
(North American TDMA), IS-95 (CDMA), CT2, DCT 900/CT3, IEEE 802.11,
DCS 1800, and Iridium.  Emerging concepts for wireless ATM are also
developed.  This course is intended for engineers who are currently
active or anticipate future involvement in this field.

Lecturer: Anthony S. Acampora, Ph.D., Professor, Electrical
Engineering, Columbia University.  He is Director, Center for
Telecommunications Research. He became a professor following a 20
year career at AT&T Bell Laboratories, is an IEEE Fellow, and is
a former member of the IEEE Communications Society Board of
Governors.

ATM DATA COMMUNICATIONS NETWORKS: Internetworking, Signaling and
Network Management (November 27-28, 1995)

This short course examines the key issues involved in designing and
implementing high-performance local and wide area networks.  Topics
include: technology drivers, data protocols, signaling, network
management, internetworking and applications.

Lecturer: William E. Stephens, Ph.D., is the Head of the Wireless and
ATM Networking Group at the David Sarnoff Research Center.  Prior to
this he was Director, High-Speed Switching and Storage Technology
Group, Applied Research, Bellcore.  Dr. Stephens has over 40
publications and one patent in the field of optical communications.
He has served on several technical program committees, including IEEE
GLOBECOM and the IEEE Electronic Components Technology Conference, and
has served as Guest Editor for the IEEE Journal on Selected Areas in
Communications.

For more information (complete course descriptions, outlines,
instructor bios, etc.) send your postal address or fax to:

Harvey Stern   or Loretta Lindley
U.C. Berkeley Extension/Southbay
800 El Camino Real Ste. 150
Menlo Park, CA 94025
Tel: (415) 323-8141  Fax: (415) 323-1438
email: southbay@garnet.berkeley.edu 

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



Recently, comp.dcom.telecom has seen some talk on the viability of
variable length phone numbers within a country (or any specific
network, for that matter). Many posters, especially those from North
America, insist on their belief that phone numbers have to be of
constant length, otherwise one must have timeouts etc.

First, let me state that I see *no reason whatsoever* why there can't be
variable length phone numbers or why a switch would have to know the
total length of the number. If you think there is a need for such
restrictions, please explain why you think so. Your reasons are not
obvious.

I would also like to point out that in Germany, where I live, telephone
numbers vary in length, in fact my voice number is +49.621.5870460 and
my modem number is +49.621.583214, area codes vary in length (2..5
digits), we have DID numbers of different lengths, and all of this
without any kludges like second dial tones, timeouts, etc. Claiming that
this is impossible is ridiculous in face of the facts.

What is a phone number? For the most part, a phone number is a *route*
through the network. The last few digits are a unique ID that maps onto

_
                                                                                                  

a particular line in the destination switch. (Whether the destination
switch is a telco CO or a PBX does not matter.)

What must a switch do during call set-up? It receives dialing
information (single or multiple digits) from an inbound trunk (or from
the line card, if it is the caller's switch), and, after collecting
enough of these, selects an outbound trunk. Further dialing info it
receives is passed on to the switch on the outbound trunk. Note that
no trunk line has to be actually connected yet. The destination switch
collects dialing info until a line that it serves is identified, then
it initiates a ring signal. Information about this is passed back the
chain of switches to the caller's switch which locally feeds a "remote
is ringing" signal. When the called line answers, again information is
passed back to the caller's switch, and now the speech circuit is
actually activated along the switch chain.

Of course the above is somewhat simplified, but it is the principle a
call set-up works by. In the ISDN age, the switches communicate using
SS7 or, in the case of ISDN BR and PRIs, both of which can be used to
connect PBXes by the way, the D channel protocol preferred in your part
of the world.

This system works with SS7/ISDN. It also worked with the prior German
phone technology, purely electro-mechanical switches. (That's relays,
levers, etc. No transistorized technology whatsoever.) With that
technology speech circuits were connected through to the next switch
already during dialing, though.

So, you want to give me a call?

Okay, you dial +49 or within Germany 0. Now you're on the long distance
level of the German Telekom network.

You dial          selects
- <6>             South western Germany.
- 6<2>            The Ludwigshafen/Mannheim area.
- 62<1>           The cities of Ludwigshafen and Mannheim themselves.
- 621 <5>         Ludwigshafen.
- 621 5<8>        The particular part of Ludwigshafen I live in.
- 621 58<70460>   That's my line. My phone is ringing!
                  (Actually, the final 0 helps selecting a particular
                  device on my ISDN line.)

When I answer the phone, the call circuit will be established and voila!

Easy, isn't it?


Christian 'naddy' Weisgerber                         naddy@mips.pfalz.de
  See another pointless homepage at <URL:http://www.pfalz.de/~mips/>.

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



WASHINGTON, D.C. -- EXCEL TELECOMMUNICATIONS, INC. Is apparently
liable for a forfeiture of $80,000 in slamming cases (switching a
person's primary long distance carrier without their prior
authorization). Common Carrier Action by the F.C.C. August 18 by NAL
(Notice of Apparent Liability) (DA 95-1833).

   According to Anna M. Gomez, a spokesperson for the F.C.C.,
"apparently solid facts", have been brought to the F.C.C.'s attention
concerning two specific slamming incidents. The complainants Mr. Bruce
Adelman of Los Angeles, CA and Mrs.  Robert J. Blake of Altadena, CA
both had their long distance services wrongfully switched to Excel
through the use of both forged signatures AND forged social security
numbers.

  To see if there was a trend here, Discount Long Distance Digest also
checked with the California State Public Utilities Commission to
investigate whether Excel has slamming complaints pending against them
on a state level.

  According to Marko Valente, Manager of Consumer Affairs at the CPUC,
Excel has had approximately 10 informal slamming complaints (24 total)
made against them by California residents during 1995. None have
resulted in more serious 'formal' complaints. The figures seem to be
at, or even below, the average level for a long distance provider.

  Chris Dance, VP of Legal Affairs at Excel stated, "It is the first
penalty ever implied upon Excel by the F.C.C. The 'slams' in question
were committed by certain independent contractors of Excel, and Excel
intends to pursue and prosecute the independent sales representatives
involved in order to recover these amounts".

  Dance also stated that Excel will file a petition for reconsideration 
with the F.C.C. within the week. Excel currently has approximately
300,000 independent sales representatives.

[Ed: Uh ... make that 299,998 independent sales agents!]

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



>     Anyone add to this list?

Square.

> (2) what is the derivation for the term "pound key", since the symbol 
on
>     telephones bears no similarity to that used for British currency.

One use for the symbol is pounds weight, as in non-metric measure.  In 
my
experience (in Canada, with heavy exposure to US writing) this is much
rarer than its use as a number sign.

>     I would hazard to guess that the answer to this derives from 
confusion
>     over the standard computer character set used in the UK, which 
differs
>     from ASCII by only one character...

No; either that's a coincidence or else someone thought it was a good 
idea
to make the substitution in the position of a symbol sometimes called by 
a
similar name.  The use for pounds weight is much older than ASCII.

> [TELECOM Digest Editor's Note: We covered this in excruciating, 
exhaustive
> detail here once before ...]

Yes, and all of it anecdotal.  I say let it die, unless this time we can
actually hear from someone with *evidence*.


Mark Brader            msb@sq.com             
SoftQuad Inc., Toronto 

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



> [TELECOM Digest Editor's Note: We covered this in excruciating, 
exhaustive
> detail here once before, but I don't fault you if you can't remember 
it,
> since it was several years ago.  Volume 8, issue 190 of this Digest, 
dated
> December 1, 1988 was devoted entirely to theories about the naming of 
#.
> This followed an inquiry just like yours in mid-November of that year, 
and
> a number of reply messages which ran from then through the end of the 
month
> and culminated in the special issue of December 1.

> And no, I am not like Ann Slanders or her sister Scabby Van Buren. I 
do
> not re-run letters I got years ago on days when the mail is a little 
light,
> which it never is around here anyway. Mr. Kealey did write and ask the
> question just recently. Anyone interested in 'How the Octothorpe Got 
its
> Name' as that issue was called, can pull it from the Archives. Look in 
the
> dusty old volume 8 stuff. Maybe I *should* re-run it. Opinions?   PAT]

Rerun it!


[TELECOM Digest Editor's Note: Okay I will, following this issue of the
Digest. Thus far the mail responses are running heavily in favor of
seeing it again.     PAT]

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



martin@kurahaupo.gen.nz (Martin D Kealey) asks:

> what is the derivation for the term "pound key", since the symbol on
> telephones bears no similarity to that used for British currency.

Neither does the name for the key.

"#" is the "pound sign" commonly used in Civil and Mechanical 
Engineering
to represent pounds of weight or force.


john

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

End of TELECOM Digest V15 #375
******************************


