TELECOM Digest     Thu, 19 May 94 23:43:00 CDT    Volume 14 : Issue 240

Inside This Issue:                           Editor: Patrick A. Townson

    ADSL and MPEG Viewing Tests (Robin Whittle)
    Cellular -> Analog Converter (burner@iia.org)
    311 Goes Statewide in New York (Dave Niebuhr)
    Distribution of WATS Numbers in the Numbering Plan (Kurt F. Sauer)
    Re: How Can I Ring Up Myself? (Kevin Ray)
    Re: How Can I Ring Up Myself? (Paul A. Lee)
    Re: How Can I Ring Up Myself? (burner@iia.org)
    Re: Bellcore to Assign NPA 500 Codes (Sergio Gelato)
    Re: Anyone Use AT&T Message Service? (Steve Cogorno)
    Re: CO Switch Types by Exchange Code (Paul Mokey)
    Re: Government Regulates Modem Redial Attempts (John Harris)
    Re: Wanted: Business Phone System (Paul A. Lee)
    Re: 800 Number Billback (Carl Oppedahl)
    Re: CNID and ANI - Will They Become One and the Same? (Jay Hennigan)

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

From: zcirrw@minyos.xx.rmit.EDU.AU (Robin Whittle)
Subject: ADSL and MPEG Viewing Tests
Date: Fri, 20 May 1994 13:18:06 +1000 


Magazine article on ADSL and MPEG-2 by Robin Whittle

ADSL stands for Asymmetrical Digital Subscriber Line - a technology
for transferring several Megabits/sec of data to the home, and several
hundred kbits/sec back to the exchange, using the existing twisted
pair copper wires - while the existing analog phone uses them as
usual. It does this by throwing a *lot* of Digital Signal Processing
at the many barriers the existing wires present to high bit-rate
communications. Each ADSL link is independent - it is not like a
shared coax cable.  For each link, there must be two transceivers -
one at the exchange and one at the home.

ADSL is seen as a way of bringing Pay TV, Video On Demand and 
Interactive Broadband Services to homes without the need to lay new 
cable.  

In the May and June editions of {Australian Communications} is a two
part article I have spent several months preparing.  16 pages of text,
tables and diagrams report on DMT ADSL and on the results of the MPEG
Test Group's recent subjective viewing tests.

The Test Group reports that for MPEG-2, for some types of program, 5
to 6 Megabits/sec is required to give quality comparable to normal
television.  This does not include 256 to 400 kbit/sec for sound.  2
Megabits/sec may be OK for film material compressed off-line, where a
human operator can fine tune the compression algorithm's attention to
the most important part of the picture.  Fast action video material is
much more demanding.

Here is an outline of the two parts of the article.

Part 1 - ADSL - Bridging the Superhighway Gap?

Introduction.
        Video On Demand.
        Provision of alternative phone services.
        Brief comparison with coaxial cable, satellite and 
        microwave Pay-TV distribution.

CAP and DMT - Two Approaches to ADSL.
        How QAM (Quadrature Amplitude Modulation) works - as in CAP.
        DMT (Discrete Multi Tone) is 249 channels of QAM.

The Twisted Pair Bottleneck.
        Physical description of buried telephone wires.
        Barriers to transmission of data :-
                Attenuation.
                Inter-Symbol Interference.
                Interference and Noise.
                Crosstalk.

HDSL - High bit-rate Digital Subscriber Line.
        Brief mention of this which provides 2 Mega bits/sec 
        duplex over 2 or 3 pairs.

Why the ANSI standards committee chose DMT over CAP.

Telecom Australia's ADSL Pilot - for 300 homes in early 1995.
        71 hour 2 Mega bit/sec Video Server from DEC.
        155 Mega bit/sec SDH fibres link to ADSL switches, each
        with 100 CAP or DMT transceivers.
        Diagram and discussion of the system - which will be 
        the second or third in the world and the first at
        2 Mega bits/sec.

Table listing the ANSI draft standard's options for downstream and 
        duplex data rates.

Discussion of cost and (dis)advantages compared to digital coax.

Part 2 - Bringing Home ADSL - The Race is On

Detailed discussion of reach limits - depending on cable and data rates.
        It seems that 6 Mega bit/sec could work to 3 km of 0.4 mm 
        cable (10 kft of 26 gauge). This - or a little more - may be 
        enough to reach between 80 and 95% of urban subscribers in 
        Australia. Many doubts remain about the distribution of cable 
        lengths, crosstalk, impulse noise and the performance of 
        practical ADSL transceivers.  Computer models predict 3.7km 
        for 6 Megabits/sec and way over 4km for 2 Megabits/sec. 
        I expect it will take two years of transceiver development, 
        extensive field trials and new surveys of the existing cables 
        before anyone will really know how many homes can be reached 
        at 6 Megabits/sec.

Cost and Availability - Assessment of plans by Amati, Motorola and 
        Aware & Analog Devices. 
        Amati plans to release a 2 Megabit/sec "Presto" and a >6 
        Megabit/sec "Overture" which will use Motorola DSPs and 
        Amati's own custom chips. Aware & Analog Devices are working 
        on multi DSP "chipset" and will evolve cheaper designs from 
        there.  Analog Devices have a low-cost 2 MHz 14 bit monolithic 
        Analog to Digital Converter which will be essential for low 
        cost ADSL transceivers.  Motorola are designing a single chip 
        transceiver for 1996 at <US$100. This is a very ambitious 
        plan.

Latest details of issue 1 of the ANSI standard for DMT ADSL which will 
        be good enough for trials. The second draft will take at least 
        another year and will contain a specification for an interface 
        to customer premises equipment which will be suitable for mass 
        production.

Total System Cost.
        Likely costs of complete system including MPEG-2 video and 
        audio decoders. C-Cube video chip needs four 4M DRAMs and may 
        cost US$35 next year. 

MPEG-2 Subjective viewing tests - as mentioned above.
        Factors which affect encoding difficulty and of some of the 
        defects which are visible at low bit rates.

Brief discussion of managing Video On Demand and other data using ATM. 
        Sydney networking company Jtec will develop an ATM/ADSL 
        switch for Telecom Australia, but no details are available yet. 

Inside DMT.
        Two diagrams depicting attenuation, crosstalk and noise issues 
        and how they affect the  and data carrying capacity of each of 
        the 249 downstream and 25 upstream QAM sub-carriers.  With two 
        pages of text which describe the passage of bits through all 
        the stages of transmission and reception.  Includes 
        description (but not explanation) of Reed-Solomon FEC, 
        interleaving and Trellis Coding. This is a terse, but complete 
        description for the more technical reader.

I believe that ADSL will happen and will probably play a role in
bringing the information super-you-know-what to our homes, schools and
businesses -- particularly in Australia where coax cable is just
starting to be laid.

As Eli Noam said, ADSL is like feeding vitamins to a horse instead of
buying a truck.  However, DMT ADSL is serious nutrition - the old
twisted pair nag *can* be run at 6.144 Megabits/sec downstream plus
640 kbits/sec duplex - while the ordinary phone is used normally.
However all claims about ADSL and other ambitious technologies being
mass producible in (the obligatory) "two years time" should be
considered in the light of (Stewart) Fist's law :-

***      A product takes twice as long to develop as planned.      ***  
***   When it arrives, it costs twice as much as first claimed -   ***
***                   and is half as good.                         ***  

                    ---*--**--***--**--*---

"Australian Communications" is a monthly magazine averaging 150 pages,
covering networking and telecommunications management with a clear
layout, great diagrams and in-depth articles. Other articles in the
May issue concern options for controlling congestion on ATM networks,
a review of a Cisco ATM router and a seven page article on client/server 
security issues.

If your library does not carry it, you can fax them on +61-2-264-2244 
for subscription and back-issue details.  Airmail subscriptions 
beyond Asia are approx $US67.

I would like to compare notes with anyone on ADSL, digital coaxial-
cable and SHF multi-megabit radio links.  I am also interested in
applications of the future world network and the social implications -
so I guess I am interested in almost everything.


Robin Whittle 
9 Miller St. Heidelberg Heights 3081 Melbourne Australia
Ph +61-3-459-2889  Fax +61-3-458-1736
zcirrw@minyos.xx.rmit.oz.au   Internet access thanks to CIRCIT 

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

From: burner@iia.org
Subject: Cellular -> Analog Converter
Date: 19 May 1994 23:25:45 -0400
Organization: International Internet Association


Does anyone know of an adapter/converter that connects to a cellular
phone (most likely in place of the handset) and provides an analog
Rj-11 jack?  Or, is there some other way to connect analog phone
devices to a cellular phone.  It needs to be able to make outgoing
calls, and the capability of incoming calls would be needed, if it's
at all possible.

Thanks.

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

Date: Thu, 19 May 94 17:09:54 EDT
From: dwn@dwn.ccd.bnl.gov (Dave Niebuhr)
Subject: 311 Goes Statewide in New York


This month's insert in NYNEX's (formerly NYTel) bill had a small item
about using 3-1-1 for TDD users to contact emergency assistance.  This
will be in place in all areas where NYNEX has a presence in its
various LATA's.

3-1-1 will remain in place until the E911 system is implemented
statewide.

I do not know what will happen with those LATAs that are small parts
of other states (CT, MA, PA and possibly VT).


Dave Niebuhr      Internet: dwn@dwn.ccd.bnl.gov (preferred)
                            niebuhr@bnl.gov / Bitnet: niebuhr@bnl
Senior Technical Specialist, Scientific Computing Facility
Brookhaven National Laboratory Upton, NY 11973  1+(516) 282-3093
                                          FAX   1+(516) 282-7688

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

From: ks@netcom.com (Kurt F. Sauer)
Subject: Distribution of WATS Numbers in the Numbering Plan
Date: Thu, 19 May 1994 21:38:27 GMT


I was unaware that 1-800 number prefixes were available to more than
one LD provider.  Someone called this "portability."  Yeah, probably
an FAQ question, but I didn't know how to determine if this were true.
If it is, how is the call placed?  Wouldn't only the LD carrier have
the true route for the call?  


Kurt F. Sauer  


[TELECOM Digest Editor's Note: It is called '800 portability', and unlike
in the past where telcos could only route toll-free calls by the first
three digits -- the exchange --, meaning exchanges were assigned to or
'belonged to' a given carrier, now routing can be done on the entire 
number. The LD carrier enters the correct information in a database which
is used by all telcos. When you dial an 800 number, your local telco makes
a quick search of the database and routes your call to the 'real' number
to which the 800 version is attached.  PAT]

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

From: kevray@MCS.COM (kevin.ray@kray.com)
Subject: Re: How Can I Ring Up Myself?
Date: 19 May 1994 14:40:47 -0500
Organization: MCSNet Services


TELECOM Digest Editor noted in response to jherl@uxa.cso.uiuc.edu (Joseph 
Herl):

> least in the Chicago 312/708 area, ringbacks are accomplished thus:

> Dial 1-57x-last four digits. The 'x' is a digit 1-9. It varies from one
> exchange to another so you have to test to see which works. For example,

I live in the 708-622 (Elgin) exchange (also including 741/742/468/464/695/
697/931/888/) in which 1-57[0-9]-my_last_four_digits produced "when dialing
a call within your area code only dial the seven digits, when ...". What 
does work in this exchange is "511" and the last four digits.

Dialing 711-last_four_digits is like dialing 911 ... ???

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

Date: Thu, 19 May 1994 18:05:15 -0400
Subject: Re: How Can I Ring Up Myself?
From: Paul A. Lee  </DD.ID=JES2CAOF.UEDCM09/@SMX.sprint.com>
Organization: Woolworth Corporation


You should be able to ring your own line if you're served by a switch
that handles (and is enabled for) revertive calling -- I think that
includes Northern and Siemens, at least.
 
To use revertive calling:

     - Go off hook
     - Dial the number for that line
     - Listen for revertive call enable tone*
          * Some switches return a repeating "zip" type tone; others return
            a gated/modified busy signal
     - Hang up
     - Line will start to ring* if revertive calling is in effect
          * Some switches will ring line normally; others will provide
            a specially gated ("distinctive") ring for revertive calling
     - Wait for ringing to stop, indicating another party on the line has
       answered
     - Go off hook and converse
     - Hang up (some switches will return a burst of ring when revertive
       calling is ended)
 
I've encountered this feature in several GTE service areas. Instructions 
for using it are published in the Milwaukee (Ameritech) book, but I haven't 
tried it here.

 
Paul A. Lee                           Voice  414 357-1409
Telecommunications Analyst              FAX  414 357-1450
Woolworth Corporation            CompuServe  70353,566
   INTERNET  </DD.ID=JES2CAOF.UEDCM09/@SMX.sprint.com>
 

[TELECOM Digest Editor's Note: I can't say I recall seeing such informa-
tion in the Ameritech book here in Chicago.   PAT]

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

From: burner@iia.org
Subject: Re: How Can I Ring Up Myself?
Date: 19 May 1994 23:28:24 -0400
Organization: International Internet Association


Joseph Herl (jherl@uiuc.edu) wrote:

> Many thanks for taking the time to respond to my question about how to
> call myself.  Your response was detailed and absolutely correct.  The
> ringback number 1-577-nnnn works here in Champaign.  I think this will
> be a big time saver when we move next week.

> [TELECOM Digest Editor's Note: Ah, so it does work throughout all of
> Illinois Bell's territory. Mine is 1-573-nnnn. I hope other readers in
> northern Illinois find this useful.   PAT]

It seems to work in Nebraska that if you dial your own phone number
and hang up, it will ring back.  That's how we always do it.


[TELECOM Digest Editor's Note: After dialing do you get a busy signal
or some special tone? If we here dial our own number, in some exchanges
we get a busy signal and in other exchanges get an intercept that 'your
call cannot be completed as dialed, please check the number and dial
again, etc ..." Even if we have call waiting installed, dialing our own
number produces a busy signal or the above recording.   PAT]

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

Date: Thu, 19 May 94 18:35:17 EDT
From: gelato@astrosun.TN.CORNELL.EDU (Sergio Gelato)
Subject: Re: Bellcore to Assign NPA 500 codes


In TELECOM Digest, V14 #237, Mike King <mk@tfs.com> wrote:

> In TELECOM Digest, V14 #233, Will Martin <wmartin@STL-06SIMA.ARMY.MIL>
> wrote:

[...]

>> is written. Are there 800-XXX exchanges in use now?

> I've seen quite a few 800-800-XXXX numbers listed.  Before portability, 
> I believe Sprint administered them.

The question was actually about 800-YXX-XXXX numbers (where Y=0 or 1).
I haven't seen any such numbers advertised in North America; but I
have seen UK numbers of the form 0839 1xx xxx.


Sergio Gelato lato@cornell.edu

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

From: cogorno@netcom.com (Steve Cogorno)
Subject: Re: Anyone Use AT&T Message Service?
Date: Thu, 19 May 1994 13:07:39 -0700 (PDT)


Said by: Mark

> I am currently living outside of the USA and usually use AT&T
> USA-DIRECT to call the US.  Well, a few weeks ago, I called, using my
> calling card, and got a busy signal.  After a few seconds, I hear a
> [computer generated] voice asking me if I want to record a message and
> have it sent at a later time followed by the prices. (I think it was
> $1.75 or $1.25, something like that per minute) All I had to do was
> press '#123' and I was prompted for a message and then was prompted at
> the end for an OK message. (i.e. press 1 or 0 or something like that)

> Well, it worked great ... has anyone else used this service?  I assume
> it has been available in the USA for a while already.

Yeah -- I use it all the time for messages.  There is also a feature
that has a real-live AT&T operator deliver it.  You can specify if you
want whoever answers the phone to get the message, or if the operator
should ask for and only release the message to a specific person.


Steve    cogorno@netcom.com
#608 Merrill * 200 McLaughlin Drive * Santa Cruz, CA 95064-1015

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

From: bkron@netcom.com (Paul Mokey)
Subject: Re: CO Switch Types by Exchange Code
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
Date: Thu, 19 May 1994 20:57:38 GMT


Michael Stanford <stanford@algorhythms.com> writes:

> I am looking for a listing of all the CO switch types in the USA by
> area code and exchange code.

You can get what you're looking for from Bellcore at (201) 740-7500.
It's available both in paper form and on diskette.

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

Date: Thu, 19 May 94 17:08 WET DST
From: joharris@io.org (John Harris)
Subject: Re: Government Regulates Modem Redial Attempts 


Mark@legend.akron.oh.us wrote:
 
> Do you have a limit on the number telephone IDs :) that you are allow
> to block calls from?  Or do they charge you on a byte-used deal? :)
> Like I always say, I'd rather have a list of allowed numbers and
> forget the rest. :)

Hang in there.  There is a CLASS feature called 'Selective Call
Acceptance' that will do what you want.  Basically it was intended for
people who will only take calls from their kids or stockbroker at
supper time; so it will have a limit of ten numbers.
 
> [TELECOM Digest Editor's Note: There is a limit of ten numbers from
> which calls can be rejected. A new entry to the list at that point
> cause the oldest entry to drop off.   PAT]

For those of you that need more than the ten numbers allowed by the
telephone company, there are boxes you can buy.  BEL-Tronics in
Georgia makes a pair of boxes with a synthesized voice which will
reject up to 100 numbers and/or all anonymous calls.  It is great for
getting rid of junk faxes.  The only limitation -- the number must call
you once, so you can move it from the incoming call list to the reject
list.

Model ND100 $ 99.95 MSRP (Number display only)
Model AD100 $109.95 MSRP (Name display if your telco sends it)
"Dealers may sell for less."

Contact BEL-Tronics Limited
        8100 Sagl Parkway
        Covington, GA 30209
        (404) 787-6500     (800) 828-8804


John Harris      BEL-Tronics Ltd, Mississauga, Ontario L5L 1J9
joharris@io.org  (905) 828-1002             Fax (905) 828-2951

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

Date: Thu, 19 May 1994 17:38:38 -0400
Subject: Re: Wanted: Business phone system
From: Paul A. Lee  </DD.ID=JES2CAOF.UEDCM09/@SMX.sprint.com>
Organization: Woolworth Corporation


In TELECOM Digest V14 #236, Drew Benson wrote:
 
> I'm looking for an inexpensive phone system designed for small-scale kinds
> of things. Not more than eight outgoing lines.
 
I have a Panasonic KX-T61610 hybrid system at home. The system comes
loaded for six loop-start trunks and 16 stations. Station sets can be
either proprietary (key/feature) sets or standard single-line sets,
including answering machines, modems, faxes, cordless, etc. Features
(with proprietary phones) include paging (group and all-call),
automatic trunk selection (in and out), some call restriction
capabilities, live SMDR output, and other basic small business or home
functions. The system is under $800, and the sets are $90-$150 from
your local Graybar Electric. Do-it-yourself installation and
programming.
 
 
Paul A. Lee                   Voice  414 357-1409
Telecommunications Analyst      FAX  414 357-1450
Woolworth Corporation       CompuServe  70353,566
INTERNET  </DD.ID=JES2CAOF.UEDCM09/@SMX.sprint.com>
 
------------------------------

From: oppedahl@panix.com (Carl Oppedahl)
Subject: Re: 800 Number Billback
Date: 19 May 1994 18:14:55 -0400
Organization: PANIX Public Access Internet and Unix, NYC


In <telecom14.239.9@eecs.nwu.edu> TELECOM Digest Editor noted in response
to Jonathan <jdl@wam.umd.edu>:

> You are not being charged for the call to the 800 number. That part is
> free to you the caller with the recipient paying for the carriage. You
> are being charged for the return collect call the Information Provider
> makes to you, which the AOS operator asked if you would accept the
> charges for. Admittedly sometimes they do not bother to call back but
> simply continue the conversation with you on the same connection, but
> none the less the AOS operator at some point asked if you would accept
> the charges for the call; when accepted, it then is like any other
> collect call.

If it is considered a collect call, then I should think billed number
screening would keep it from happening.  Yet, on my mother's telephone
bill, a charge for an 800 number appeared, despite the fact that there
was billed number screening on that line.


Carl Oppedahl AA2KW    Oppedahl & Larson (patent lawyers)
Yorktown Heights, NY   voice 212-777-1330  


[TELECOM Digest Editor's Note: Had the call been handled by AT&T, Sprint,
MCI or your local telco, then billed number screening *would* have prevented
it from getting through. The thing is, many AOS companies do not consult
the database used by the major players. Even your local telco will advise
you that (should you request billed number screening) they will not abso-
lutely guarentee you will never be billed for a collect or third-number
call ... just that *they* will not originate such a charge. But, all is
not lost: some of the others maintain their own similar database. For
example, Telesphere, a long distance billing service for many AOS's and
Information Providers who bill through telcos maintains its own database
of people who do not want such charges. They'll gladly add you to their
list on request; then the AOS/COCOT's they represent will get the same
automatic decline of charges when someone uses one of those phones (or
services) that Bell would give. Ditto a couple other COCOT/AOS operations;
they tend to work from the Telesphere database as well. 

Generally whevever I get a charge on my phone bill for a collect (or
whatever) call from a COCOT, I just call the customer service number
for that carrier and get added to their negative listing. I must be on
six or seven such databases by now, and as a result I don't think
there is a COCOT/AOS left in the USA that can stick me with charges.
If you sign up for billed number screening with your local telco, that
will end it where telco and the Big Three are concerned; contacting the
Telesphere people will take care of about 80-90 percent of the rest,
especially where the more expensive and obnoxious 'charge for an 800
call' IP's are concerned.   PAT]

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

From: jay@rain.org (Jay Hennigan)
Subject: Re: CNID and ANI - Will They Become One and the Same?
Date: 19 May 1994 18:10:52 -0700
Organization: Regional Access Information Network (RAIN)


In article <telecom14.237.10@eecs.nwu.edu> padgett@tccslr.dnet.mmc.com 
(A. Padgett Peterson) writes:

> With the FCC mandate for CNID service, is it not possible that the
> telcos will use this to drop ANI? Also it has been mentioned that
> "911 service requires special trunk lines and equipment". Clearly CNID
> does not and needs only a low-cost display. Will this make local 911
> response a possibility?

The special 911 trunks are associated with ANI and ALI (Automatic
location idintification), and the PSAP (Public Safety Answering Point)
system associated with 911 allows calls to be transferred to other
agencies with the ANI and ALI passed.  In come cases, I believe that
the 911 PSAP operator can seize the calling line as well.  The 911
response is often as local as a city police or fire departmant
dispatch center, although the ALI lookup tables can be 100 miles away
at the LEC's data processing center.


Jay

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

End of TELECOM Digest V14 #240
******************************

