TELECOM Digest Sat, 8 Jan 94 09:22:00 CST Volume 14 : Issue 19 Inside This Issue: Editor: Patrick A. Townson Re: Book Review: "The Phone Book" by Carl Oppedahl (Carl Oppedahl) Re: "Anonymous Call Rejection" - Could be Dangerous (Richard Masoner) Re: "Anonymous Call Rejection" - Could be Dangerous (Anthony E. Siegman) Re: "Anonymous Call Rejection" - Could be Dangerous (James R. Saker Jr.) Re: Surcharge for Tone Dialing to be Dropped (Carl Oppedahl) Re: Surcharge for Tone Dialing to be Dropped (Ed Greenberg) Re: Surcharge for Tone Dialing to be Dropped (A. Padgett Peterson) Re: Surcharge for Tone Dialing to be Dropped (Chris Labatt-Simon) Correction: Re: Help Needed With V.42bis (Jim Graham) Re: Hayes' New Modem (Jakob Hummes) Re: Communication Over Power Lines? (Michael D. Griffin) Re: How are VCR Plus Codes+ Generated (Peter Capek) Sprint (Dvorak) Modem Offer - Finally (Dan Osborn) 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. 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 compilation-copyrighted by Patrick Townson Associates of Skokie, Illinois USA. We provide telecom consultation services and long distance resale services including calling cards and 800 numbers. To reach us: Post Office Box 1570, Chicago, IL 60690 or by phone at 708-329-0571 and fax at 708-329-0572. Email: ptownson@townson.com. ** 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 gatewayed to Usenet where it appears as the moderated newsgroup comp.dcom.telecom. It has no connection with the unmoderated Usenet newsgroup comp.dcom.telecom.tech whose mailing list "Telecom-Tech Digest" shares archives resources at lcs.mit.edu for the convenience of users. Please *DO NOT* cross post articles between the groups. 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: oppedahl@panix.com (Carl Oppedahl) Subject: Re: Book Review: "The Phone Book" by Carl Oppedahl Date: 7 Jan 1994 17:52:11 -0500 Organization: PANIX Public Access Internet and Unix, NYC In varney@ihlpe.att.com writes: > In article oppedahl@panix.com (Carl > Oppedahl) writes: >> The state-to-state differences are discussed in my book about phone >> service. >> [TELECOM Digest Editor's Note: What's this about your book about phone >> service? Please review it for us and tell us how to obtain copies. PAT] [most of review omitted here -- thank you by the way to Mr. Verney!] > Some complaints: > -ANI is defined as the service we here call "Caller ID", which will > be confusing when talking to those who know the difference. Yes, Mr. Varney is right. I incorrectly used the terms as if interchangeable, which of course they are not. If and when there is another edition I will correct this. > -Quad wire is blessed as a method of installing 2-line telephones, and > as a general inside wiring method. Again Mr. Varney is right. While I am pleased with most of what I wrote, I am very embarassed that I did not then appreciate the difference between quad and twisted-pair for multiline purposes. As readers here are aware (1) many home have quad already in place so adding twisted-pair is more work and (2) quad often yields annoying crosstalk. I wish I had made the latter point in my book, and hope to cover that point in another edition. > -The cellular information should include information on ESN-cloning > and other problems with cellular service. Again he is right. > -Information (see below) useful to apartment dwellers is indexed under > the term "multiunit buildings", not under "apartment". (In general, > there is little "lawyer-speak" in the book.) Yes, and what's annoying is, I supplied an index and the publisher did not use it -- they used one prepared by an index consultant that they had used on other books. Oh, well. > Al Varney - I have no connection with Consumers Union, except as > a happy customer. I have no connection with any lawyer, > except as an unhappy customer. Well, thank you for taking the time to write it up. Now, dear readers, here is how we can get a new edition that corrects the bugs Mr. Varney mentioned, and that reflects everything else people in this newsgroup might want to add -- you can guess. People would have to buy the present print run. So, trot down to your local bookstore and clear those shelves. Buy extra copies for use as gifts. Or call up Consumer Reports Books and order it by phone. But seriously, thank you for the writeup. Carl Oppedahl AA2KW Oppedahl & Larson (patent lawyers) Yorktown Heights, NY voice 212-777-1330 ------------------------------ From: cendata!richardm@uunet.UU.NET (Richard Masoner) Subject: Re: "Anonymous Call Rejection" - Could be Dangerous Organization: Central Data Corp., Champaign, IL Date: Fri, 7 Jan 1994 21:44:22 GMT In article drharry!aboritz@uunet.UU.NET (Alan Boritz) writes: > Then you probably don't receive a lot of calls from telemarketing > idiots and nosy scam artists. We go through periods at work when > we're inundated with those, and calls from telemarketing machines (our > exchanges are low numbers in the 201 area). Telemarketing calls are > an enormous time-waster, and more than half of the investment scam > callers are pushy and rude. Invade my privacy at home with a useless > sales pitch AND hide your CNID from me and I'll redefine the word > "rude" for you. ;) Many (not all) telemarketing calls actually originate from somewhere outside of your area code (places where rent and labor is cheap). Rejecting anonymous callers doesn't work for them. > If you're hiding your identity from me (privacy block), then I don't > want to talk to you. My time is worth more than yours (anonymous > caller, that is) and I don't appreciate it being wasted. Many people do have legitimate privacy concerns, and don't want their phone numbers to be known outside of a select circle. Just my observations. Richard F. Masoner Central Data Corporation 1602 Newton Dr., Champaign, IL 61821 (217) 359-8010 x251 ------------------------------ Date: Fri, 7 Jan 94 16:57:53 PST From: Anthony E. Siegman Subject: Re: "Anonymous Call Rejection" - Could be Dangerous > Then you probably don't receive a lot of calls from telemarketing > idiots and nosy scam artists. We go through periods at work when > we're inundated with those, and calls from telemarketing machines ... > Telemarketing calls are an enormous time-waster, and more than half > of the investment scam callers are pushy and rude. Ditto here. In past two days San Jose Mercury telemarketers have managed to ring all four university extensions on my secretary's desk (selling newspaper subscriptions to Stanford University office extensions? -- but then, who expects intelligence from telemarketers). Let me once again pitch the simple idea that telemarketers should be allowed total freedom to call anyone -- but required to do it with CNID from a special "telemarketing area code" prefix, like 300 or 400 or ??? (just like the "Advertisement" warning at the top of commercial inserts in reputable magazines). Those who wanted could then buy a cheap black box to block all such calls. No First Amendment problems, no "do not call this number" databases to prepare and maintain, burden of protection entirely on the callee (but easily done), etc. ------------------------------ From: jsaker@cwis.unomaha.edu (James R. Saker Jr.) Subject: Re: "Anonymous Call Rejection" - Could be Dangerous Organization: University of Nebraska at Omaha Date: Fri, 7 Jan 1994 19:22:27 GMT Ron Schnell writes: > I have anonymous call rejection enabled on my phone in Miami, FL, and > someone tried to call me from a cellular phone that was installed in a > rental car in San Diego in their rental car and got the rejection > message. > I assume that the cellular rental company uses some ultra-cheap LD > service (to make the most amount of money possible on the $2.00/minute > rental charge!) that uses a local out-going line in Miami that > disabled CID. I've got US West Cellular service in Omaha, Nebraska (all you can eat a month for $150!). Several of my friends and business associates who have caller ID services have noticed that whenever they receive calls from me on my cellular phone, they appear as anonymous calls. Attempts to use last-call-return also fail (with some useless message). Evidently it's not just cheap cellular providers which demonstrate this problem ... Jamie Saker jsaker@cwis.unomaha.edu Chief Operating Officer Business/IS Major Synergistic Communications Univ. Nebraska at Omaha voice: (402) 680-8280 fax: (402) 391-7283 ------------------------------ From: oppedahl@panix.com (Carl Oppedahl) Subject: Re: Surcharge for Tone Dialing to be Dropped Date: 7 Jan 1994 17:24:46 -0500 Organization: PANIX Public Access Internet and Unix, NYC In Eric De Mund writes: > Dave Niebuhr in TELECOM Digest V14 #15: >> NYTel, as part of a multi-million dollar rate rollback has been >> ordered to reduce the cost of touch-tone dialing from $1.35 to $.50 >> per month which is still not enough. > Given that backwards state of affairs, maybe my dad *is* telling me > the truth when he says that he can't even *get* touch-tone service at > his home in central Nassau County (Westbury), Long Island, New York, > telephone number (516) 333-xxxx. Incredible. I don't know the situation now, but a few years ago a friend in Westbury had three lines in the house, one of which was a 516-333. The 516-333 had been in place for a decade or more, and he kept it because it was a flat-rate line -- no charge for local calls. Makes me think that 516-333 was some sort of ancient equipment, a stepper exchange, maybe. Carl Oppedahl AA2KW Oppedahl & Larson (patent lawyers) Yorktown Heights, NY voice 212-777-1330 ------------------------------ From: edg@netcom.com (Ed Greenberg) Subject: Re: Surcharge for Tone Dialing to be Dropped Organization: Netcom Online Communications Services (408-241-9760 login: guest) Date: Sat, 8 Jan 1994 14:20:02 GMT In article Eric De Mund writes: > Given that backwards state of affairs, maybe my dad *is* telling me > the truth when he says that he can't even *get* touch-tone service at > his home in central Nassau County (Westbury), Long Island, New York, > telephone number (516) 333-xxxx. Incredible. Since 516-333 is served out of the Westbury DMS-100, it would surprise me if it couldn't handle touchtone. Now, NYTel may have some foolish reason for not providing it, but be assured that 516-333 isn't step or some other ancient technology. Ed Greenberg edg@netcom.com Ham Radio: KM6CG ------------------------------ Date: Fri, 7 Jan 94 08:39:39 -0500 From: padgett@tccslr.dnet.mmc.com (A. Padgett Peterson) Subject: Re: Surcharge for Tone Dialing to be Dropped > In addition, it is phasing out the optional business Flat Rate and > untimed Message Rate plans for businesses in upstate NY and imposing > timed message rate for them. This is the scary part simce everywhere I go I see regional carriers attempting to eliminate "flat" and "unmetered" plans. As telecommuting and information hightway access begins to take hold, the elimination of unmetered local service is the biggest threat to individual connectivity that I can imagine. Of course, the biggies (Compu$erve, Plodigy, etc.) will have 800 numbers and just pass the cost along, but one might expect amateur BBSs, SLIPs, and the like to become much less popular. The biggest threat would be to the infant telecommuting industry and the home office which relies on unlimited local service and the best means for achieving the Clinton/Gore "20% reduction in commuting" would go up in smoke. True, TANSTAAFL still applies and I suppose metering is inevitable particularly since it is both cheap and desirable for the Telcos. The only advantage that I can see for the consumer would be that with metered service, the subscriber would have a right to a call detail listing the individual calls by called number, time, and duration. Chilly today, Padgett [TELECOM Digest Editor's Note: Chilly is an understatement, Padgett. Four degrees below zero at 9:00 AM this Saturday morning is not my idea of a pleasant spring day in Chicago! :) PAT] ------------------------------ From: pribik@rpi.edu (Chris Labatt-Simon) Subject: Re: Surcharge for Tone Dialing to be Dropped Date: 7 Jan 1994 22:51:01 GMT Organization: Rensselaer Polytechnic Institute, Troy NY, USA Eric De Mund writes: > Given that backwards state of affairs, maybe my dad *is* telling me > the truth when he says that he can't even *get* touch-tone service at > his home in central Nassau County (Westbury), Long Island, New York, > telephone number (516) 333-xxxx. Incredible. I have a friend in Islip (Nassau County) who has touchtone. I though this was a capability that was in all switches manufactured in the last umpteen (how much is an umpteen anyway?) years, and that if a customer wanted pulse service, the phone company had to disable touchtone. Anyone? Anyone? Chris Labatt-Simon Internet: pribik@rpi.edu Design & Disaster Recovery Consulting CIS: 73542,2601 Albany, New York PHONE: (518) 495-5474 FAX: (518) 786-6539 Subscribe to the Lotus Notes Mailing List - e-mail me for info.... ------------------------------ From: jim@n5ial.mythical.com (Jim Graham) Subject: Correction: Re: Help Needed With V.42bis Organization: Future site of Vaporware Corporation (maybe). --Teletoons (NW) Date: Fri, 7 Jan 1994 16:13:08 GMT The purpose of this posting is to correct some major technical goofs in another post. These corrections come right out of the ITU-T (ex-CCITT) text for V.42 and V.42bis, as well as info from one of the authors of both standards. General comments, of course, are mine. :-) In article PURWIN@XANADU.XYPLEX.COM (Janusz Purwin tel 508-952-4711) writes: > Well don't worry about if it does work or not. Firstly V.42 requires > that both modems have to have that feature enabled. Secondly it is > most useless feature ever put into modem. Its good for marketing > people to brag about and give false advertising about how faster modem > will transmit data without pointing out when it happens. First off, V.42 *IS* an important feature, especially for high-speed modems. If you didn't have some type of error control, you could run into all kinds of problems. Remember, high speed modems (e.g., V.32bis and the up-and-coming V.34) really stretch the limits of a normal POTS line. I won't bore everyone here with the details, since that's not going to be anything new to anyone anyway. Second, V.42 (and MNP3) strip off the start/stop bits, thus using only 8 bits per character instead of 10. For a V.32bis connection, this means going from a throughput of absolutely no more than 1440 cps to somewhere around 1650 cps to 1724 cps (after protocol overhead). See the discussion over in comp.dcom.modems for more details on this. But when have you ever seen a vendor 'brag' about this? > The V.42 uses Limpel-Ziff compression scheme Sorry, but V.42 doesn't do any compression, period. V.42 is an error control protocol, as is clearly indicated by the title of ITU-T (ex-CCITT) Recommendation V.42: "Error-Correcting Procedures For DCEs Using Asynchronous-to-Synchronous Conversion" (originally in all-caps). V.42 is an HDLC-based error control procedure. It operates in one of two modes: LAPM (Link Access Procedure for Modems), which is its primary mode, and an alternate mode specified in Annex A, which is basically an MNP4 clone (added to provide support for older modems that don't have V.42). If you can find anything about data compression in Recommendation V.42, you must be reading a different version than the one that was written by the CCITT (now the ITU-T). Now, assuming that your reference to V.42 was a typo, and you really meant V.42bis ... > The V.42 uses Limpel-Ziff compression scheme that is based on > generating dictionary as you transfer a file. What that mean is, it > will not compress as you type. First off, V.42bis uses a modified version of Lempel-Ziv-Welch compression. Various extensions were added to LZW to make it more effective in a modem environment where it would be required to compress continuous streams of data. It compresses whatever data it can, regardless of whether that data is typed by you, is a screen of data from the remote computer, or is a file being transferred. Second, even if V.42bis only worked when *FILES* were being transferred, and not when text screens, etc., were moving, would you please explain to me how it's supposed to know the difference? :-) Think about it ... > But here is the catch normally ALL files are compressed You seem to be assuming that the only use for high-speed modems is downloading files from a BBS. This is, in fact, far from the truth. There are lots of people using modems to access various other online applications, and V.42bis can definitely help a *LOT* in this case. And even if all you're doing is snarfing up some file from a BBS, isn't it nice to have those file listings move faster? Hey, if I'm grabbing a file from a BBS, I usually have something I want to do WITH that file -- I'd rather get on with that than sit there waiting for screen after screen of info. > by PKzip, ARC or ARJ LHA GIF programs. Those are using precisely > same algorithm as V.42. As already covered above, V.42 isn't data compression, and V.42bis (which *IS* data compression) uses a modified version of LZW that is designed specifically for the modem world. In fact, zip, etc., usually do better than V.42bis, so where possible (and it isn't always possible) you're better off compressing files with something like zip or gzip prior to sending them. > So those files are not compressible. If you try to compress them > again the file size will be larger than original. Not true. Unlike MNP5, V.42bis is nice enough to not expand pre-compressed data, so the worst you'll get is 1:1. For more details, refer to section 7.8 of Recommendation V.42bis ("Data compressibility test"). > ... So the benefits of V.42 for the user are minimal! That depends on what the user is doing. The benefits for YOU may be minimal, and that's fine. But just remember that there are other modem users in the world, and they don't all do things exactly the same way you do. Later, jim 73 DE N5IAL (/4) < Running Linux 0.99 PL10 > jim@n5ial.mythical.com ICBM: 30.23N 86.32W || j.graham@ieee.org Packet: N5IAL@W4ZBB (Ft. Walton Beach, FL) E-mail me for information about KAMterm (host mode for Kantronics TNCs). [TELECOM Digest Editor's Note: My thanks to Jim for submitting this correction. It is very difficult from where I sit to catch some of the errors in the more complex technical articles which appear here in the Digest, thus the importance of readers sending in corrections when they are needed. Never hesitate to send in corrections and to be sure they catch my eye given the high volume of mail received, be sure to add some phrase in the subject line such as 'correction to posting' or similiar. PAT] ------------------------------ From: hummes@osf.org (Jakob Hummes) Subject: Re: Hayes' New Modem Date: 7 Jan 1994 21:04:43 GMT Organization: Open Software Foundation In article , md@maxcy2.maxcy.brown.edu (Michael P. Deignan) writes: > Of course, I don't know if this is how Hayes does it, but remember, > you can only modulate a sine wave one of three ways: amplitude, phase, > and frequency. > Ain't technology wonderful? Yes, it is. But there is an absolute limit (Shannon's Law). The question was about the transmission over a *real* phone line. And that means there exists *noise*. The limit of bps is proportional to the logarithm of the signal to noise ratio. Unfortunately I don't remember the constant factors. Jakob Hummes ------------------------------ From: mgriffin@access3.digex.net (Michael D. Griffin) Subject: Re: Communication Over Power Lines? Date: 7 Jan 1994 19:38:21 GMT Organization: Express Access Online Communications, Greenbelt, MD USA James H. Haynes (haynes@cats.ucsc.edu) wrote: > I believe the power companies also use carrier current for signaling > and controlling their relays and things, again working on the high-voltage > side of things so they don't have to go through transformers. Actually many of them (most) have discovered that they can run a fiber optic cable right along side or even inside the high voltage cables since the opticial signals are immune to the electrical interference ... now if someone could only figure out how to transmit electric power via fiber cable the power companies would really be happy. ------------------------------ Date: Fri, 7 Jan 94 15:14:54 EST From: Peter Capek Subject: Re: How Are VCR Plus+ Codes Generated VCR Plus codes are a "secret" encoding of the channel, start date and time, and length of a program. Gemstar seems to have elected to try to keep the encoding secret, so as to maintain their ability to sell the device, and also to sell to the newspapers the codes. This may be because they couldn't get an effective patent or other form of protection. Unfortunately, they seem not to have anticipated that this strategy would be interpreted by many as a challenge. As a result, almost all details of the encoding were deduced and published in a paper, published in Cryptologia about two years ago. As far as I know, there's no other protection on the encoding, so that no legal barrier prevents a newspaper (at least, one which isn't already under contract to Gemstar) from creating the codes itself and publishing them (modulo the missing details), although there is undoubtedly protection on the VCR Plus trademark itself. Peter Capek ------------------------------ From: dosborn@Internet.cnmw.com Date: Fri, 07 Jan 94 15:28:01 EST Subject: Sprint (Dvorak) Modem Offer - Finally Pat: As a final effort to obtain my sprint modem, I scanned back issues for Diane Worthy's number. The number associated with her is no longer in service. However, in my search I came across the number for Shawn Larimer. One article listed him as the person in charge. I called that number and left a message. Well, I just received a return call, not from Mr. Larimer, but from Don Sivesind (913-624-5136). He was very nice, even cheerful. When I breifly explained to him my tale of woe, he (much to my delight) said that he would order me a modem right away. It turns out that instead of setting up a new account (which would have trigged a modem order) they re-activated on old account. Well, I'm a "happy camper" now, and not "so" down on Sprint's customer service. Although, this still leaves David in a quandry about what to do with his extra modem. Dan Osborn [TELECOM Digest Editor's Note: Thanks for the followup on this. I'm glad to hear Sprint was willing to work along with you. Regards David and his extra modem, I wonder if he has been staying awake all night wondering what to do about it. :) Hey, he can send it to me if nothing else; somehow I will find a way to sacrifice one of the empty slots in my 386. :) I'll try to stay warm today as it is miserably cold here in Chicago, and the forecast is for sub-zero weather for a couple days. Otherwise, have a nice weekend! PAT] ------------------------------ End of TELECOM Digest V14 #19 *****************************