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) 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 GEnie. It is also gatewayed to Usenet where it appears as the moderated newsgroup 'comp.dcom.telecom'. Subscriptions are available at no charge to qualified organizations and individual readers. Write and tell us how you qualify: * telecom-request@eecs.nwu.edu * The Digest is edited, published and compilation-copyrighted by Patrick Townson of Skokie, Illinois USA. You can reach us by postal mail, fax or phone at: 9457-D Niles Center Road Skokie, IL USA 60076 Phone: 708-329-0571 Fax: 708-329-0572 ** Article submission address only: telecom@eecs.nwu.edu ** Our archives are located at lcs.mit.edu and are available by using anonymous ftp. The archives can also be accessed using our email information service. For a copy of a helpful file explaining how to use the information service, just ask. ************************************************************************* * TELECOM Digest is partially funded by a grant from the * * International Telecommunication Union (ITU) in Geneva, Switzerland * * under the aegis of its Telecom Information Exchange Services (TIES) * * project. Views expressed herein should not be construed as represent-* * ing views of the ITU. * ************************************************************************* Additionally, 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. 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. ---------------------------------------------------------------------- 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 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 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 [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 wrote: > In TELECOM Digest, V14 #233, Will Martin > 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 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 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 ------------------------------ 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 TELECOM Digest Editor noted in response to Jonathan : > 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 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 ******************************