TELECOM Digest Thu, 22 Jul 94 00:13:30 CDT Volume 14 : Issue 329 Inside This Issue: Editor: Patrick A. Townson Reading the TELECOM Digest May be a Crime (Steve Bunning) CWA Charges Sprint With Illegal Action (Phillip Dampier) Secret Life of Bank Machines: Simple Tech Explanations Sought (P. Rukavina) Information on FiberOptics Requested (Matthew Scott Weisberg) Telephony Cards Other Than Dialogic - Recommendations? (Karyn German) LDDS Metromedia Calling Card Confusion (Dan Srebnick) Digital Telephone Systems (Robert Ambrose) Book Review: "Internet Public Access Guide" by Hughes (Rob Slade) Correction to 703 -> 540 Prefix List (Paul Robinson) International Math Olympiad Result (Cedric Hui) Conference Call Circuit? (Todd McLaughlin) Re: Last Laugh! Telephone Connections as Explained on Usenet (bkron@netcom) 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. ---------------------------------------------------------------------- Date: Wed, 20 Jul 1994 01:42:14 EDT From: Steve Bunning Subject: Reading the TELECOM Digest May Be a Crime [TELECOM Digest Editor's Note: This time around dear readers, I decided to save the best for first. Let's all have a good laugh to start this issue at the expense of the Pacific Telephone and Telegraph Company Security Department. They must really think they are hot stuff. PAT] ----------- In a recent issue of the TELECOM Digest, there was some joking about it being a felony to read information about telecommunications. This reminded me of something that happened to me in the mid-70s. At the time, I had subscribed to a newsletter out of California called TEL or the Telephone Electronics Line published by the Teletronics Company of America. It was similar to 2600 magazine and the TAP newletter having articles on telecommuncations topics, but with a phone phreak flavor. After receiving the publication for over a year, it suddenly stopped coming. Sometime thereafter I received a notice from the Pacific Telephone and Telegraph Company Security Office. The text of their notice read as follows: "On March 25, 1976, the Superior Court of California, County of Los Angeles, entered an injunction in favor of The Pacific Telephone and Telegraph Company and against Teletronics Company of America, and others. Your name appeared on a list (provided under Court order) of subscribers, or potential subscribers, to material previously published and distributed by Teletronics Company of America. Accordingly, for your protection and benefit, you are hereby given the following notice: IT IS A VIOLATION OF STATE AND FEDERAL LAW TO USE ANY INSTRUMENT, DEVICE OR SCHEME TO OBTAIN ANY TELEPHONE SERVICE WITHOUT PAYMENT OF THE LAWFUL CHARGES THEREFOR. IT IS ALSO A CRIME TO PROVIDE INFORMATION TO ANY PERSON WHICH IS USEFUL FOR SUCH PURPOSE. IN MANY STATES, THE POSSESSION OF OR DISSEMINATION OF PLANS OR INSTRUCTIONS FOR SUCH DEVICES IS A CRIMINAL OFFENSE. VIOLATIONS OF THESE LAWS ARE VIGOROUSLY INVESTIGATED AND PROSECUTED. ACCORDINGLY, YOU ARE URGED TO DESTROY ANY AND ALL WRITTEN MATERIAL OR DEVICE YOU MAY HAVE WHICH MAY VIOLATE ANY OF THESE LAWS. THIS STATEMENT IS BEING SENT TO YOU BY ORDER OF THE SUPERIOR COURT OF CALIFORNIA, COUNTY OF LOS ANGELES." End of notice. So you see, subscribing to telecom publications may be riskier than you imagined. I wonder, does this mean I should burn any back issues of the TELECOM Digest that I have? Perhaps reading the Digest is only a misdemeanor and not a felony :-) [TELECOM Digest Editor's Note: Isn't that precious! They want to fight, maybe somone or more people should give them one. This reminds me of a similar case here in the late 1970's when Channel 44 was operating in many parts of the USA as 'pay television' with a scrambled signal. You could watch their movies, but to do so you had to have one of their decoding boxes, and of course you got one of those when you signed up for the service. Purchase of a decoding box got to be a joke however, as more and more pirates began building them and selling them out of the back of their car. Everytime Channel 44 would change the system slightly then the pirates would soon change their product to meet the new specs. The answer from the pay-tv people was to stage raids at the homes of the pirates and seize all the equipment, arrest them, etc. One aquaint- ence of mine was 'in the business' (the pirate business that is) and he got busted for selling decoders out of the back of his van in the parking lot at 7/Eleven. They had several answers: if you claimed your product was 'genuine' they got you on fraud charges; it obviously was not the real thing. If you claimed it was type accepted by the FCC then that was also fraud; in subscription television systems type acceptance does not issue on decoders alone, only on entire systems including the transmitter, etc. If you sold 'educational kits you assemble on your own' with the circuit board already put together and maybe a single knob or two which had to be screwed on in order to make it a 'kit you built yourself' then you were an accomplice to the theft of services done by the persons who purchased your 'kit'. They had it made, or so they thought; they had an answer to every angle the pirates tried to use. Thinking back to the days of Prohibition in the United States in the 1920's, I recalled how Anheiser-Busch (the makers of Budweiser Beer) had survived during those lean years: They sold kits by mail order which people could use at home to brew their own 'near beer', a con- coction which *was* legal during prohibition. Anheiser-Busch sent the nearly completed distillery (you had to screw in a couple of pieces) along with 'brewing instructions for near-beer'. Every page of the very detailed instruction book cautioned against using certain ingred- ients in certain quantities, i.e. 'do not use (ingredient x) and only use the amount we tell you of (ingredient y), because if you put 'x' in there in quantity 'y' you will manufacture beer, and that is not legal!' Of course you know the purchasers of the little distillery and brewing kits put in plenty of 'x' and 'y', but they had been warned by Budweiser against doing it, so as not to violate Prohibition. With that in mind, the 'Radio Hobbyists Guild' was started. The Guild had one project, and one project only in mind: to educate people in the ways to *avoid breaking the law* where subscription television decoder boxes were concerned. The Guild published a very detailed instruction book complete with schematics showing how Channel 44 boxes worked, so that whatever the reader happened to be building in the way of electronic devices he could be sure to *not configure the components in the way shown here* to avoid breaking any laws, etc. Every page of the schematics was plainly noted "Caution, do not put electronic components together in the way shown in these diagrams becase by doing so you might be breaking the law." The reader was frequently warned that 'in the event you are building some kind of electronic device and *accidentally* (my emphasis) construct a decoder box then you must be certain not to actually use it for that purpose until you have (1) obtained type acceptance from the FCC, (2) notified Channel 44 that you are in possession of it and agreed to pay their monthly fees, and (3) gotten their permission in writing to do so.' The little book published by the Radio Hobbyists Guild was given away to anyone who sent a dollar or four postage stamps with a self addressed large envelope to a certain post office box in downtown Chicago. I think a couple thousand copies were sent out in all. Channel 44 knew it was just a ploy -- thinly veiled BS -- but how do you go about making someone quit urging others to obey the law? PAT] ------------------------------ From: phil@rochgte.fidonet.org (Phillip Dampier) Reply-To: phil@rochgte.fidonet.org Date: Wed, 20 Jul 1994 13:30:05 -0500 Subject: CWA Charges Sprint With Illegal Action CWA CHARGES SPRINT WITH ILLEGALLY SHUTTING LATINO SUBSIDIARY A WEEK BEFORE UNION VOTE Sprint Long Distance illegally shut down a San Francisco subsidiary that markets services to the Spanish-speaking community just one week before the 177 workers were set to vote on unionizing in a National Labor Relations Board election, the Communications Workers of America declared in charges filed with the NLRB. CWA is requesting that the NLRB seek an injunction to re-open the office under Section 10(j) of the National Labor Relations Act, and also is calling for the labor board to proceed with a representative election. The unfair practice charges were formally filed against Sprint late yesterday in San Francisco. The union charged that Sprint abruptly closed the office on July 14 to retaliate against the workers for seeking to organize -- approximately 70% had petitioned for an election -- and to block what portended to be the first successful unionization campaign so far at the aggressively anti-union long distance company. CWA also charged that the action was intended to intimidate employees at other Sprint facilities who have been seeking to organize despite fierce management opposition as laid out in Sprint's "Union-Free Management Guide." Sprint bought La Conexion Familiar ("The Family Connection") in 1992 after contracting with the company for several years to sell Sprint long distance service and provide Spanish language customer service to the Latino community throughout the west and mid-west. La Conexion's total workforce numbers 235, mostly women of Latin American origin. La Conexion's business represents about seven percent of the Latino market niche in long distance nationwide, which is growing 2 1/2 times the rate of the market overall. In what CWA President Morton Bahr described as "a brutal mass execution," Sprint management suddenly secured the La Conexion offices the afternoon of July 14, and told the workers to collect their belongings and leave the facility after first submitting to body searches by the security force. "Workers burst into tears, at least one woman fainted, and paramedics were summoned," the San Francisco Examiner reported of the scene. Captain Philip Harvey, who led the paramedic team, said: "There was a point where we were going to offer the services of a psychological counseling team because we feared they might start calling 911 and overwhelm the system." One female worker was taken to the hospital for further treatment for what was described as a "psycho-social crisis." Shortly after the closing took place on July 14, a top Sprint official who was briefing several CWA officials on the action disparaged La Conexion workers as mainly "illegal immigrants" who spoke "Hispanic" and who had "bought" their $7 an hour jobs with bribes. While Sprint claimed that it closed the operation for economic reasons, in fact this past March the company general manager told the {San Francisco Chronicle} that La Conexion had been growing as much as 20% a month for the past two years and that he projected a tripling of annual revenues by 1996. As recently as last month, a Sprint national newsletter featured La Conexion as a unique and "very successful" marketing enterprise. "They told us that the reason they're closing is they were losing money but that's a lie," said one of the fired workers Argelia Ardon. "They closed us because we were organizing." Threats that Sprint would pull the plug on La Conexion if the workers voted to unionize had been widely rumored, drawing letters of concern from telecommunication union leaders in Germany and France, where Sprint is seeking a partnership with the national phone companies. ------------------------------ Date: Wed, 20 Jul 1994 15:33:58 +0100 From: Peter Rukavina Subject: Secret Life of Bank Machines: Simple Tech Explanations Sought I'm looking for simple technical explanations of how bank machines and bank machine networks work for a radio series on "everyday technology" I'm working on. Specifically: (1) How is my "PIN Number" kept secret from everyone but me? Is it stored on the magnetic stripe on my "bank card" or in some form in the bank's "central computer?" Or somewhere else? (2) How is the security of tranmissions between bank machines and the "central computers" ensured? I have an old "Discover" magazine article which talks about a 64-bit digital key generated by "white noise" which is placed in both bank machine and central computer and used to DES encrypt everything that passes between the two... is this accurate? (3) How is the traffic between different banks' networks (and different "networks of networks" like Cirrus and Plus and, here in Canada, Interac) handled? Do all banks' computer speak "the same language" in the same way that all Internet computers speak TCP/IP? (4) I'm assuming the process of, say, withdrawing $20 from a machine goes something like this: - I stick my card in, card reader gets my "client number" from the magnetic stripe, asks me for my PIN Number, somehow verifies that I entered the right one (or not) - the local computer in the bank machine presents me with a menu of possible transactions (perhaps based on information it got about my various accounts from the "central computer"?) and takes me through a series of questions... Withdraw... Savings... $20.00 - the bank machine computer the packages up the request and sends it off to "central" which verifies (a) that I have enough money in my account and (b) that I haven't gone over my "daily limit" and, if everything's okay, sends a signal to this effect back to the bank machine, - the bank machine, having received an "okay to dispense" signal, spits out $20 and sends back a "debit $20 from his account" message to "central." (5) How do bank machines "count money?" This would seem like a hard sort of thing to pull off, especially given that you have to be right pretty near well 100% of the time. (6) Besides the recent "Chemical Bank computer error results in double withdrawls from 100,000 accounts" problem in February, are there other large-scale problems which have occured with banking machine networks? (7) A 1992 New Scientist article talks about how the process of "shouldering" people when they're entering their PIN, then collecting their carelessly discarded receipt and, using the card number printed on the receipt, using "readily available equipment which costs less that $1600" to crank out a duplicate card using "published documents" as a guide. Is such equipment still "readily available" and what would the "published documents" be? Is this a widespread problem in the U.S.? Many thanks for any and all information. Peter ------------------------------ From: moodyblu@umcc.umcc.umich.edu (Matthew Scott Weisberg) Subject: Information on FiberOptics Requested Date: 20 Jul 1994 08:15:31 -0400 Organization: UMCC, Ann Arbor, MI Recently, I posted a request for information on WANs for a project I was researching for the City of Novi, Michigan. Well, it turns out that the cable company here, MetroVision, is under an agreement to the city to provide Fiberoptics cable to every single municipal building! MetroVision is wiring the entire Oakland County with FiberOptics, expected to be completed by the end of 95. They have a very impressive network already it seems. Many of the schools here have something called INET, basically, the schools are using MetroVisions "B" cable to "share" classes on video and such. Supposedly, the original agreement was that Metrovisoin was to run two cables of 56 channels each to provide 112 channels to subscribers, however, they only run one cable, the "A" cable, to subscribers. I saw some maps of their current network, and they apparently have 750Mhz(?) of bandwith available in the Novi area. Anyway, what I need to know is what equipment would I need to attach to their fiber to our 10BASET ethernet networks in each building? How many strands would we need? They are running at least 12 strands to each building I think ... it could be more. I also need to know some places to order the equipment from, as I need to get pricing ideas. The engineer from Metrovision that came said it is not cost effective to run fiber between "campus" buildings. They said there is already a "shadow" cable (coax) running between the buildings and we could use that and get like 1.54Mbps of bandwith. I disagree and don't feel this is enough bandwith, especially with IPX/SPX being the bandwith hog it is. I also thought that costs were coming way down on fiber. Am I mistaken? As usual, any information you can provide would be greatly appreciated! Matt Weisberg, CNE MILLIWAYS - Computer and Network Consulting PP-ASEL 21650 West Eleven Mile Road #202 Amateur Radio: KF8OH Southfield, MI 48076 Internet: moodyblu@umcc.umich.edu (810)350-0503 x11 Fax:(810)350-0504 ------------------------------ From: kmgerman@netcom.com (Karyn German) Subject: Telephony Cards Other Than Dialogic - Recommendations? Organization: Netcom Online Communications Services (408-241-9760 login: guest) Date: Wed, 20 Jul 1994 21:14:12 GMT Could someone recommend telephony cards other than those by Dialogic? I know that Dialogic is the defacto industry standard for call processing applications, but we need an option that has drivers for BSDI Unix. I would be interested in any alternatives, even if you don't know about the BSDI support -- I'll research this myself. Please email me at kgerman@marketplace.com. Thanks ever so much! Karyn German Cyberspace Development, Inc. kgerman@marketplace.com Specialists in Internet Commerce 303-759-1289 http://marketplace.com ------------------------------ From: dan@islenet.com Date: Wed, 20 Jul 94 11:10:54 EDST Subject: LDDS Metromedia Calling Card Confusion Organization: Isle-Net Telecommunications (BBS +1 908 495 6996) I use an LDDS/Metromedia calling card to call New Jersey from my workplace in NYC by dialing their 800 274 1234 number. The reason I normally use them is that they offer a no surchage calling card. Anyway, for the last couple of days, after I enter my calling card number, I get an "MCI Operator" who asks me what number I am calling from and what my calling card number is. It appears that Metromedia is having some kind of switch problem in the NY area and is routing calls via MCI. I declined to complete the calls without knowing who would bill me and for how much. No one at LDDS/Metromedia or MCI could provide an explanation for this rerouting of calls via an alternate carrier. When I tried to report the problem to LDDS/Metromedia, I was place on hold for about fifteen minutes and gave up. Does anyone know what and where the problem is? Dan Srebnick ------------------------------ From: ambrose1@netcom.com (Robert Ambrose) Subject: Digital Telephone Systems Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Wed, 20 Jul 1994 22:07:37 GMT I am acting as a non-paid volunteer in an attempt to put a well known disability service organization on line. The problem I am facing has to do with their present telephone system in relation to the fact that they do not have an overabundance of spare cash on hand at the moment. They had an SRX digital phone network installed three or four years ago and as I am sure all of you well know modems operate on analogue systems. On each desk in this organization there sits a phone with three incoming digital lines which we can't access. Somehow we have to be able to grab one of those lines to use with the modem. Installing new dedicated lines is cost prohibitive. SRX has offered the solution of an analog station cards for the box in the basement which will service six people each, at a cost of $1800 per card. There are over 90 people within this agency that could use communications, so forget the cards. What would Thomas Edison have said? "Damn the torpedoes, Let's find a solution", maybe. I need a solution, they need a solution. robert ambrose 508-362-3456 or email either your solution or number ------------------------------ Date: Wed, 20 Jul 1994 12:44:03 MDT From: Rob Slade Subject: Book Review: "Internet Public Access Guide" by Hughes BKINTPAG.RVW 940427 SSC P.O. Box 55549 Seattle, WA 94155 206/527-3385 FAX: 206/527-2806 sales@ssc.com "Internet Public Access Guide", Hughes, 1994, 0-916151-70-0, U$2.95 This book (pamphlet) is a quick, and very cheap, introduction to the Internet. On the other hand, it doesn't explain much, and a lot of it is not about the Internet. It can't be considered a reference guide since it isn't easy to find the information, and there isn't a lot there. The book mentions that the best place to get information about the Internet is on the Internet, but very few sources are mentioned. Given the brevity of the book, it is surprising that two pages are spent selling other SSC books, and twelve more in a brief introduction to UNIX. However, the basics are here, particulary if the user is either working from, or dialling into, a UNIX service. In that case, sysadmins may find this a very handy "first step" for users. Service providers running strictly UNIX systems may find it much cheaper to buy these starter pamphlets (available in boxes of 240, apparently) rather than build documentation from scratch. For those providing Internet access from a UNIX platform, this would be a handy and inexpensive first guide to users. For those on other platforms, or with proprietary interfaces, it would be less useful. copyright Robert M. Slade, 1994 BKINTPAG.RVW 940427. Distribution permitted in TELECOM Digest and associated newsgroups/mailing lists. Vancouver ROBERTS@decus.ca Institute for Robert_Slade@sfu.ca Research into rslade@cue.bc.ca User p1@CyberStore.ca Security Canada V7K 2G6 ------------------------------ Date: Wed, 20 Jul 1994 15:17:24 EDT From: Paul Robinson Reply-To: Paul Robinson Subject: Correction to 703 -> 540 Prefix List Organization: Tansin A. Darcos & Company, Silver Spring, MD USA In a prior message I posted the list of prefixes changing from Area Code 703 to area code 540 effective July 15, 1995. In transcribing that list from the list in the paper, I missed a line by typing in the first three or four entries, then accidentally moving down to the next line and starting at entry number four or five there. My apologies for this error. The corrected list, which I have checked, is as follows: The following prefixes in the 703 area code will change to area code 540, effective July 15, 1995: 220 223 224 225 226 228 230 231 232 234 236 238 245 248 249 251 253 254 258 259 261 262 265 268 269 270 279 286 289 291 297 298 320 322 326 328 332 333 334 336 337 338 340 341 342 343 344 345 346 347 348 349 350 362 363 364 365 366 371 372 373 374 375 376 377 380 381 382 383 384 386 387 388 389 390 395 396 398 399 420 423 427 429 432 432 433 434 436 439 443 445 452 456 459 460 462 463 464 465 466 467 468 470 472 472 474 475 477 479 480 483 489 495 496 498 499 520 523 529 530 531 542 543 544 546 547 552 554 559 561 562 563 564 565 566 567 568 570 574 576 579 580 582 586 587 592 593 597 599 621 622 623 624 625 626 627 628 629 632 633 634 635 636 637 638 639 645 646 647 650 651 652 653 654 655 656 662 663 665 666 667 668 669 672 673 674 675 676 677 678 679 682 686 687 688 694 699 721 722 723 726 727 728 729 731 732 738 740 743 744 745 747 752 755 762 763 766 770 771 772 773 774 775 776 777 778 779 782 783 785 786 788 789 794 796 822 825 828 829 831 832 833 835 837 839 840 852 853 854 856 857 858 859 861 862 863 864 865 867 868 869 870 871 872 873 877 879 880 881 882 884 885 886 887 888 889 890 891 894 895 896 897 898 899 921 923 925 926 928 929 930 932 933 935 937 939 940 942 943 944 945 946 947 948 949 951 952 953 955 956 957 961 962 963 964 965 966 967 969 972 973 977 980 981 982 983 984 985 986 987 988 989 991 992 994 995 996 997 999 ------------------------------ From: chui@netcom.com (Cedric Hui) Subject: International Math Olympiad Result Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Wed, 20 Jul 1994 05:47:51 GMT Not a telecom news from Hong Kong, but I think some people may like to know. Subject: USA Kids Score In Math Race Date: Tue, 19 Jul 94 6:20:12 PDT HONG KONG (AP) -- Six high school students from the United States achieved a historic first at the 35th International Mathematical Olympiad in Hong Kong today -- they all had perfect scores. Officials said never in the history of the competition have all members of a team managed to score the maximum 42-point score in geometry and other mathematical tests. "I am very proud of the performance of our team," said Professor Walter Mientka of the University of Nebraska-Lincoln, leader of the U.S. team. "Each member demonstrated great mathematical creativity and was an outstanding representative of the United States." More than 600 students from 70 countries and territories competed in the contest, organized by London's International Mathematical Olympiad Advisory Committee and the Hong Kong Mathematical Society. A total of 192 medals were awarded with golds going to students who scored at least 40 points, silver to those who had at least 30 points and bronze for those with at least 20 points. China finished second with three golds and three silvers, and Russia was third with three golds, two silvers and one bronze. The American team members were: Jeremy Bem of Ithaca High School in New York, Aleksandr Khazanov of Stuyvesant High School in New York City, Jacob Lurie of Montgomery Blair High School in Maryland, Noam Shazeer of Swampscott High School in Massachusetts, Stephen Wang of Illinois Mathematics and Science Academy, and Jonathan Weinstein of Lexington High School in Massachusetts. ------------------------------ From: Todd McLaughlin Subject: Conference Call Circuit? Organization: a2i network Date: Wed, 20 Jul 1994 06:08:32 GMT I've made a simple circuit between my two phone lines so I can host a conference call. The sound quality is rather disappointing, though. The second call that is made sounds very distant. I'm guessing a simple amplifier would fix the problem. A friend said I needed to get a phone transformer, but he didn't seem to know much about it. Has anyone else done this with promising results? Or if someone can tell me a bit about the phone transformer ... Thanks! Todd McLaughlin ------------------------------ From: bkron@netcom.com (Kronos) Subject: Re: Last Laugh! Telephone Connections as Explained on Usenet Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Wed, 20 Jul 1994 05:55:14 GMT jlundgre@ohlone.kn.PacBell.COM (John Lundgren) writes: > [TELECOM Digest Editor's Note: John Lundgren found this gem of wisdom > on some Usenet group somewhere and passed it along ... Aw, come on. Based on the grammar and spelling, I'd say its just some young kids. But, maybe not! I'm hearing "Dueling Banjos!" I remember picking up the phone on our old Western SXS when I was a kid (or was it my friend's Automatic GTE SXS?) and noticing that there would appear to be no voltage for just a moment because there was no sidetone. Immediately upon going off hook, there was sidetone, then no sidetone, then dialtone. I never thought this was because they were "switching batteries." (That was pretty funny) I just assumed that the line was momentarily open while the line finder worked. But maybe the guy authoring the posted opinions drew the wrong conclusion. ------------------------------ End of TELECOM Digest V14 #329 ******************************