TELECOM Digest Fri, 24 Feb 95 00:40:00 CST Volume 15 : Issue 119 Inside This Issue: Editor: Patrick A. Townson ISDN on CNN's Science and Technology Week Show (Ed Goldgehn) Caller Id Service For Equivalency Lines - First Line Only? (Paul Chehowski) Re: The Philosophy of CallerID (Charles R. Azer) Help Needed With US Robotics Sportster (Randy Hoes) Re: Is Origin Cell on a Cellular Call Logged? (Sam Spens Clason) Re: Is Origin Cell on a Cellular Call Logged? (Kris Trimmer) Re: Switch Architectures Literature (fredbg@ax.apc.org) Information Wanted on Ericsson Switch (Steve Bauer) Re: What is DMS-100? (Steve Bauer) Re: Information Wanted About DMS Switches (Scott Miller) Re: Grim Changes for Net (A. Padgett Peterson) Re: Pair Gain Line Problem, Help! (Mike Sandman) Northern/BT Agreement Continues (Dave Leibold) Re: Wireless RF Manufacturers (Eric Nelson) Re: E(TACS) and GSM (John Scourias) What is ESF and D4? (davethez@netcom.com) Re: March 7 Bellcore Meeting in DC (leob@netcom.com) NUtmeg (Gary D. Shapiro) 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 America On Line. It is also gatewayed to Usenet where it appears as the moderated newsgroup 'comp.dcom.telecom'. Subscriptions are available 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: 500-677-1616 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. A suggested donation of twenty dollars per year per reader is considered appropriate. See our address above. 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: edg@ocn.com (Ed Goldgehn) Subject: ISDN on CNN's Science and Technology Week Show Date: 24 Feb 1995 04:39:58 GMT Organization: The INTERNET Connection, LLC Reply-To: feedback@ocn.com Here's a heads up on this weekend's Science & Technology Week show on CNN. Over the past few weeks, Open Communication Networks and BellSouth Telecommunications have been assisting CNN on putting together a segment on ISDN and its use for telecommuting. BellSouth Telecommun- ications provided the ISDN lines to CNN and to Miles O'Brien's home (the host of the show). OCN provided the integration of all computer, communication, and software components to give CNN the applications they asked for -- for the record -- in a very limited timeframe. At this time, we are not certain what exactly will show up on the segment of this half-hour show. We have been told that a follow-up is scheduled which will include more standard telecommuting applications than this individual segment is focused on. We are very interested in receiving any feedback about the segment so that we may pass it on to CNN. We hope to continue the series on a more regular basis bringing to the show additional applications of ISDN both on the "bleeding" edge (as some of these were) and more generic applications for use by the general telecommuter and ISDN end-user. Please send any comments or suggestions via e-mail to feedback@ocn.com. The show airs at 11:00 a.m. EST on CNN this Saturday (2/25). It is repeated on Sunday at 12:30 EST. Actual times may vary across time zones so be sure to check your local listings for Science and Techology Week. The applications which were taped for the show include the following: 1) Video Conferencing via ISDN with Intel's Proshare Package 2) Intel's Proshare Premier (shared white board) during #1 3) WWW access via IBM's WaveRunner and FTP's Explore On-Net Software 4) Internet E-Mail via ISDN FTP's Mail-OnNet software 5) Video Conferencing via IP (using OnNet 1.1) over 128K ISDN with Invision's Software and Intel's Video Capture Board - ISDN was via a Gandalf 5242i Bridge (without compression). 6) Internet Phone via ISDN (in conjunction with Invision Video Conferencing 7) WWW at 128K using Spyglass Enhanced Mosaic (next release) via Gandalf's 5242i Bridge (without compression) 8) cc:mail (CNN's internal mail system) via nfs via ISDN through the Gandalf 5242i Bridge (without compression) connected to OCN's Metropolitan IP/CO and then routed to a Livingston's Firewall Router connected via a Bonded 128K connection using Motorola's UTA220 Items #1 through #4 were taped at the home of one of BellSouth's employees. OCN provided FTP's software and assisted in the configuration and implementa- tion of the WaveRunner on an existing ISDN circuit which also served the Intel Proshare equipment on a limited S/T bus. Items #5 through #8 were configured, implemented and installed by OCN. All connectivity to Internet for the program was provided by The INTERNET Connection, LLC in Atlanta (404-419-6100 or sales@ticllc.net) We have been asked to provide {CommunicationsWeek} with a story about how the technology was integrated for the show. While no guarantees have been given about their publishing the article, they have indicated a significant interest in the information. In any event, I will be writing that article and will make it available to anyone send an e-mail request (feedback@ocn.com). Ed Goldgehn E-Mail: edg@ocn.com Sr. Vice President Voice: (404) 919-1561 Open Communication Networks, Inc. Fax: (404) 919-1568 [TELECOM Digest Editor's Note: I'd like a copy of that article to share with Digest readers. Please send it here also if that's possible. PAT] ------------------------------ From: paulc@hookup.net (Paul Chehowski) Subject: Caller Id Service For Equivalency Lines - First Line Only? Date: Thu, 23 Feb 1995 22:57:08 Organization: Sulis Computing Help, I'm working on an IVR system that is heavily dependent on Caller-ID to identify callers to the system. We arranged to have our lines put in, and I was shocked to find out that if I wanted a single 1-800 number to access the system, I had to set up the two lines that we needed in the local office as equivalency lines, and that as equivalency lines I would only get caller id on the first line of the group. Unfortunately I could only talk to a local order taker, who couldn't explain to me technically why this is the case, and they were unable to suggest any work arounds and were unwilling to pass me on to anyone technical to discuss the issue. I know the Caller-ID information is transmitted between the first and second ring to the line. For some reason, if the first line is busy, then the second line can not obtain the Caller-ID information and pass it down the local loop to the subscriber at the end of the line. Questions: 1. Can anyone out there obtain Caller-ID information for all lines of an equivalency group, from their local phone company? 2. Can anyone provide me with a technical information of what's happening in the switch that does not allow Caller-ID information to be transmitted in this case? (or a contact to someone within Bell Canada that could answer this question) 3. Any suggestions for an alternate method of having a single 1-800 number pass over to multiple local lines, with Caller-ID information provided to all of the multiple lines. Thanks for any help anyone can provide. This system is being used to provide information to clients with sensory disabilities, many of who will have vision impairments, thus we want to set it up so they have to press as few keys as possible on their telephone to use the system. Paul Chehowski paulc@hookup.net Sulis Computing ad771@freenet.carleton.ca [TELECOM Digest Editor's Note: Well I don't know about the telco where you are located, but here, Caller-ID gets passed just fine to the various lines in a hunt group. For example I have CID on by my lines. The first line hunts to the second when it is busy. I have one CID display box fed through a Radio Shack automatic line selector switch. That's the device that when a single line phone is plugged in, either of two lines ringing will toggle the internal switch in the box and feed the ringing line to the single phone. Instead of a phone, I feed my CID box from that unit. (I have a two line phone nearby.) When either line rings independently, the box shows the number. When the main line is busy and it gets a call the second line rings of course, and the CID box shows the number. So I think someone at your telco misled you, unless they have software that's different than everyone else. Now you *do* have to pay for CID on each line; you can't get by with paying for it just on one line; maybe that is how the rep misunderstood you. Based on the way your message read, I assume you are subscribing to some long distance carrier which supplies ANI in the form of Caller-ID when you get a call. If your telco still persists that they cannot send CID intended for the first line on to the hunt line as needed, then go back to your LD carrier and have *them* supply the hunt group in the form of two 800 lines; one to each of your two numbers. Have the LD carrier make your listed 800 number hunt to a second 'overflow' 800 number and do the work at that end. The first 800 will feed your first line and the second (transparent to the user, hunted) 800 number will feed your second line. Then tell your local telco: two lines, each separate; two Caller-ID's, one on each line. Your LD carrier will fix things on his end so that instead of a single 800 number handled like DID which just splashes all over the place, feeding you to the extent you can handle it, your 800 will handle one call, and one call only at a time. When its in use, the next incoming call hunts to another 800 and it in turn handles one call, and one call only, directed to your second line. Long ago, before having single 800 numbers for lots of calls at one time, we had to do it that way; literally an actual 800 number for each call we wamted to be able to accept. You want to take twenty calls at a time, get twenty 800 numbers. No more, thank goodness, but it is one way to work around telcos who refuse to take what is handed to them and hunt with full features on their end. You can also get the LD carrier to actually terminate on phones at your end direct rather than outdialing what he gets. You might want to consider that also; cut the local telco out of the picture entirely. PAT] ------------------------------ From: crazer@crl.com (Charles R. Azer) Subject: Re: The Philosophy of CallerID Date: 23 Feb 1995 20:45:48 -0800 Organization: CRL Dialup Internet Access (415) 705-6060 [Login: guest] Jeremy Schertzinger (jeremyps@eskimo.com) wrote: > I don't like the stuff, myself, I'll stick to espresso coffee. btw, > don't you think Mountain Dew looks like urine? :-) No. It looks like radiator fluid! Charles R. Azer [TELECOM Digest Editor's Whimper: Come on now guys! Enough is enough! Exactly what is 'radiator fluid'? Do you mean anti-freeze? PAT] ------------------------------ From: rhoes@tiac.net (Randy Hoes) Subject: Help Needed With US Robotics Sportster Date: Thu, 23 Feb 1995 19:46:07 Organization: Consultant I bought a US Robotics Sportster V.34 etc. and I can't make the fax portion work. I have spent mucho time with Datastorm (Procomm+) trying to isolate the problem to no avail. Datastorm says the ROM chip in the US Robotics is old and should be replaced. I picked up a rumor from my SLIP provider today that it is generally known that US Robotics has a problem with the ROM. Has anyone heard of the problem and is US Robotics helping us? Thank you, Randy Hoes ------------------------------ From: d92-sam@flum.nada.kth.se (Sam Spens Clason) Subject: Re: Is Origin Cell on a Cellular Call Logged? Date: 23 Feb 1995 21:09:10 GMT In chuckc@hpfcla.fc.hp.com (Chuck Cairns) writes: > Is the origin cell on a cellular call logged? Can such information be used in an American court of law? How "easy" is is for the authorities to obtain it? The reason I ask is that it can in Sweden court. Some years ago there was a case of a man being sentenced to jail on the basis of his cell-phone records. He had burglered a house but pleaded not guilty. He had an alibi which stated that he hadn't been within 5 km from the burglered house. The police knew that he had a cellphone mounted in his car. When they examined the records they found that he had indeed used his phone during his "alibi". Telia concluded that he could not have been farther away from the scene of the crime than 500m. > [TELECOM Digest Editor's Note: To find out the answer to this, I turned > to our resident expert, Kevin Mitnick ... ... he says they are, > unfortunatly. Uh, I know this is a rude question to ask, but have you > some reason to wish they were not? PAT] Maybe, maybe not. It is a rather relevant question. A couple of years ago your location could be computed to a couple of hundred meters square or more. Now that distance has shrunk dramatically due to the shrinking size of radio cells. In just couple of years your cellphone will give you away just as effectively as a (civillian) GPS terminal. Ethical question; is this god or bad?! Sam Sam Spens Clason ------------------------------ Date: 23 Feb 95 19:07:32 EST From: Kris Trimmer <73772.1042@compuserve.com> Subject: Re: Is Origin Cell on a Cellular Call Logged? In a recent issue, chuckc@hpfcla.fc.hp.com(Chuck Cairns) asked: > Is the origin cell on a cellular call logged? To which the Esteemed Moderator replied: > [TELECOM Digest Editor's Note: To find out the answer to this, I > turned to our resident expert, Kevin Mitnick ... ... he says they > are, unfortunately. Uh,I know this is a rude question to ask, but > have you some reason to wish they were not? PAT] Pat, I can't answer if Chuck has a reason, but his question does lead to one I am curious about. Let's suppose (purely hypothetically) That I am a former pro football player and part time sportscaster with a promising acting career (Thats promising as in - " I keep promising I'll get better - but I don't"). I have recently been charged with the particularly gruesome murder of my ex-wife and her friend. One key to my guilt or innocence lies in my alibi for where I was at 10:15 at the alleged time of the murder. Unable to challenge this time of death due to the well known "barking dog as a time of death indicator" (a well known forensic legal principal recently upheld in the case of Ted Bundy Vs. Lassie), I am forced to prove I was elsewhere at or around the time of death. Remembering that I placed a call to my loving main squeeze Paula on my cellular phone from my driveway at about 10:20, I ponder whether or not the origin cell on a cellular call is logged and if so, could that information prove that I made the call from my driveway (or at least near enough to originate on the closest cell to my house), and not from my ex wife's neighborhood which is located seven to ten minutes away by car. Not trusting the local police department to investigate (since they seem to be staffed mostly by people whose training and expertise in investigation would instill a feeling of superiority in even the likes of Deputy Barney Fife) I instead turn to the learned subscribers of the noted electronic journal TELECOM Digest. So what do you think? Anyone have any knowledge of the distance between cells in the,say, Brentwood area of Los Angeles? Could the origin cell log help me/hurt me? Does the carrier actually save these logs? Pat, I'm sure this isn't what Chuck was asking about, and yes, I obviously have to much free time. Kris [TELECOM Digest Editor's Note: Well you know, for some time now I have been threatening to pre-empt the regular programming here in lieu of úÿ giving full time coverage of the hypothetical trial (I say hypothetical because it is too much of a joke to be a real trial) of Mister Simpson. The trial of the century looks like it will last a century at the rate it is going. PAT] ------------------------------ From: fredbg@ax.apc.org (Fred) Subject: Re: Switch Architectures Literature Organization: Rede APC -- Nodo AlterNex Date: Thu, 23 Feb 1995 21:46:41 GMT In article , walterz@bnr.ca says: > I am looking for some papers/books that would describe switch > architectures . My interest is in both hardware architectures and > software architectures and their developement over last few decades. > Could anybody please direct me to right sources on the area in the > forms of thesis/articles/books. You can find it in info.itu.ch [TELECOM Digest Editor's Note: Indeed, the ITU is a great place to begin your search for many topics relating to telecom. I've been very pleased with their support of this Digest over the past year and hope they choose to continue for a long time to come. Definitly look into their information service. PAT] ------------------------------ Date: Thu, 23 Feb 1995 05:18:17 -0600 From: Steve Bauer Subject: Information Wanted on Ericsson Switch Is anyone using or administering a Plexar on an Ericsson switch? I will be installing one in March and wonder what I will face. I am running a majority of my 30 locations on a Northern DMS100 Plexar (Centrex) arrangement. Since the Ericsson switch is in another town, we plan to use Tie Trunks to connect the two Plexars and maintain four digit dialing company wide. I've just not heard too many good things about this switch. Furthermore, it does not offer the Custom Rearrangement Service like that available on the DMS100. What a drag, have to issue service orders to change anything. Steve ------------------------------ Date: Thu, 23 Feb 1995 05:19:39 CST From: Steve Bauer Subject: Re: What is DMS-100? Stan, The DMS100 is manufactured by Northern Telecom and is a very popular switch used in central offices. About five years ago, my company was faced with the same situation you are dealing with. The actual biggest shock to our employees was going to a new prefix and we forced them to go from three digit to four digit dialing at the same time. You will probably not have any trouble at all with your modem. Things should actually work better. I have found on the DMS100 we are using, which was installed by Southwestern Bell Telephone, that you do not need to place a coma or pause after dialing the 9 access code. The system reacts fast enough that you can just have your modem dial 9 followed by the desired number. One little trick to remember, and it works both with voice and modem calls is to place the "#" at the end of your dialing string. This will greatly speed up the processing of your call. Without it, the DMS100 is sitting there waiting to see if you are indeed finished before it completes your call. It's not a bad habit to get in to. When you are dialing to another four digit extension on your campus, no need to use the "#", it will ring instantly. You will probably be given some new features and some feature codes may also change. Hope this answers your questions. Steve ------------------------------ Date: Fri, 24 Feb 1995 04:50:48 +0000 From: scott miller Subject: Re: Information Wanted About DMS Switches Reply-To: smiller@bnr.ca Organization: Bell-Northern Research Ltd. In article , vardy@engr.mun.ca (Vardy David) writes: > Hi! I'm an electrical engineering student preparing for my first > interiview with my first big telecommunications company. I was > wondering if anyone could give me a simple description (or complex if > you have time) of what a DMS Switch is and what it does. What does DMS > stand for? What kind of maintenance and software is required to > maintain it? DMS stands for 'Digital Multiplex Switching', which is used to describe Northern Telecom's family of central office switches. Variants of the DMS include the DMS-100 (end-office, POTS and ISDN), DMS-200 (toll), DMS-300 (international gateway), DMS-MTX (cellular), DMS-STP (CCS7), etc. The components of a DMS system have been developed over the years using many different processor families, programming languages, and operating systems, with a common goal of achieving a the maximum call-processing capacity and very high availability. (System downtime targets are on the order of 30 seconds/year) The role of the switch is to process telephone calls. A POTS call is the simplest. The switch monitors for off-hook, provides dialtone, collects dialed digits, figures out who you want to talk to, rings the other line, waits for answer, sets up the voice path through the switching fabric, sets up the call, and then waits for one end to hang up so that it can reverse this process. Oh, and it bills the call, too. (Very important!) And it does all this a couple of hundred times per second. The software that maintains the system is crucial, and constitutes a large proportion of the library, which was counted at 25+ Million lines of code a few years ago. It's a very big, complex, realtime system. It can be a real challenge to keep it all working, and it can be damn hard work, but there's a whole lot to be learned from it. Good luck with the interview. (NT or BNR, I presume?) (Oh, on the DMS-100 thread: I recall reading here that an example of a difference you may find in CO switches is that some let you dial through a stutter dialtone, and some don't. Things like modem dialing strings may need to be tweaked. I imagine the differences in external behaviour would be relatively minor.) Scott Miller, in the bowels of Bell-Northern Research smiller@bnr.ca aa438@freenet.carleton.ca ------------------------------ Date: Thu, 23 Feb 95 09:45:27 -0500 From: padgett@tccslr.dnet.mmc.com (A. Padgett Peterson) Subject: Re: Grim Changes for Net > And yes, that child pornography: truly the pedophiles have a field day > on the commercial services; after all on CIS/AOL/IRC you are whoever you > say you are; who is to say otherwise? At least on Internet's own version > of chat (Internet Relay Chat or IRC) anomynity is relatively more difficult > to pull off; your username@site is there for people to see. I suspect that the anonymity afforded by the services have a lot to do with the problem. Now that Caller-ID is available in many areas, the "heavy breathers" have to go elsewhere and the net is a natural. My opinion is that we do not need to make context illegal (and with all of the different juristictions probably can't since so much is dependant on "the eye of the beholder". Rather, if the identity of all users were available through something like a "white pages" -- I know there is one, look for the first Peterson -- then I *suspect* that the problem would become manageable. Currently the traditional response -- personal retaliation is difficult. The sad part of this long posting is that female users are being forced to change their usernames for protection. IMNSHO they are being victemized by terrorists -- is there any other word ? -- and *that* is the injustice. On earlier frontiers, those who were impolite had to do it face to face and risked retaliation. The crude cowards of the net hide behind a mask of distance an impersonal electrons and communicate from their closets. Now if I were more mercenary, I could see a value of being able to trace any message to its source. It is certainly doable and not very difficult, just an "unexplored territory" at the moment. However I do think that Internet Caller-ID would be a better solution to the problem than the "thought police" since censorship does nothing to stop those who are rude, only society/culture can do that. Warmly, Padgett ------------------------------ From: mike@sandman.com (Mike Sandman) Subject: Re: Pair Gain Line Problem, Help! Date: Thu, 23 Feb 1995 21:15:14 GMT In article Matt writes: > I have been told by a Pac Bell (i'm in CA) tech that the reason that I > cannot connect above 9600 is because I'm on a "Pair Gain" line to the > C.O. My roommate has no problem, the tech says he's on a copper line > to the C.O. > Problem: Pac Bell refuses to change me over to a copper line, saying > that they are only required to provide a 'voice-grade' line which only > has to support transfer speed of 1200 bps (HA HA HA HA HA). > What can I do? Does anyone have a work-around? Has anyone experienced > this same problem? I've tried four different modems, all with the same > problem. But if I use my roommate's line, everything works great! (For > practical reasons, I can't use his line all the time, he runs a business > on it). The usual cause of trouble connecting or staying connected at high speeds is high loop current coming from the pair gain equipment (or right from the CO or a PBX for that matter). If you have a digital voltmeter with a DC ma scale, you should be able to determine your loop current by putting the leads in series with one side of the line, making a call (with the electricity going thru your meter) and reading the ma off the meter. For good data communications, it should read between 23 and 27ma DC. If it's over 27ma, which it probably will be, you will need to get the current down below 27ma. It is not unusual to get 50ma, and sometimes as much as 80ma of loop current. In addition to preventing high speed connections, 40ma and up can burn out whatever you've got connected to the line, except standard old non-electronic 2500 type telephones. If the loop current is between 23 and 27 ma, you are looking at a problem other than loop current. If the loop current is below 23ma, the phone company must bring the current on the line up to 23ma. If it's above 27ma, the phone company won't reduce the current for you, since their high spec is 110ma (a holdover from the early 70's before there was much electronic stuff out there). To bring the current down, you can use 1/2 or 1 watt resistors in series with BOTH sides of the line (the red and green wires). For every 100 ohms you put on the line, you will reduce the loop current by about 1ma. While you reduce the loop current, you are also reducing the AC voltage containing the audio on the line - 100 ohms reduces the level of the line about 1db. If your loop current is at 33 ma, and you stick 600 ohms in series with each side of the line, you will drop the db level from say -6db (which is a good average), to -12db. This would probably work OK for the modem, since it doesn't like real high audio levels anyway, but you would have trouble hearing people talk on the line at that point. You could put these resistors just before the modem -- and NOT in series with with your telephone, which would still allow you to talk. If you have 40ma of loop current, you would need to put in 1300 ohms of resistors, which would lower the db level to -19db at which point even your modem wouldn't be able to hear on the line. We sell a gizmo called a Loop Current Attenuator which has a series of dip switches that you keep flipping until you see the loop current on the line go below 27ma. At that point, you remove your meter and leave the Loop Current Attenuator in place. The Loop Current Attenuator uses a network of resistors and capacitors to leave the db level alone so you or your modem can still hear on the line, while reducing the loop current. We sell the modular Loop Current Attenuator for $32.95. 30 day moneyback guarantee. 708-980-7710. Mike Sandman ------------------------------ From: Dave.Leibold@superctl.tor250.org (Dave Leibold) Date: 23 Feb 95 22:00:13 -0500 Subject: Northern/BT Agreement Continues [from Bell News (Bell Canada), 20 Feb 95] Northern Telecom and British Telecom have added five more years to the agreement which allows British Telecom to market Northern's business telephone systems -- the Meridian 1 PBX and Norstar key system -- to its customers. The agreement could generate more than $600 million in revenue for our sister BCE company. British Telecom has also placed an order with Northern forf $125 million worth of Digital Multiplex Switching (DMS) 100 systems. Fidonet : Dave Leibold 1:250/730 Internet: Dave.Leibold@superctl.tor250.org ------------------------------ From: mater@primenet.com (Eric Nelson) Subject: Re: Wireless RF Manufacturers Date: Wed, 22 Feb 1995 01:09:56 MST Organization: Primenet In article jdi@access.digex.net writes: > Anybody out there know who the "good" manufacturers of RF subsystems > for cellular systems are? Assuming there is at least one good one? Good is a relative term. I also don't know exactly what you mean by RF subsystems. The major manufacturers are AT&T, NTI, Ericcson and Motorola. North American cellular system are proprietary in that you have to by the cell sites and swithes from the same vendor. Hope this helps. ------------------------------ From: jscouria@neumann.uwaterloo.ca (John Scourias) Subject: Re: E(TACS) and GSM Organization: University of Waterloo Date: Thu, 23 Feb 1995 14:30:13 -0500 Alexander Cerna writes: > Can someone explain to me what E(TACS) and GSM are in detail? There > are around five cellular phone service providers in our country, and > most of them use E(TACS). One uses GSM, and says that this is the > latest technology in cellular telephony. They say that it would make > international roaming possible (although they say that it isn't > possible right now). > Also, this service provider that uses GSM says that they're the only > provider that's 100% digital. One of the implications of this, they > claim, is that their phones can't be cloned as easily as the analog > ones. Is this true? Also, they say that analog systems are very > prone to charge errors. Is this also true? Or are they just trying > to scare me from going to the other service providers? During the development of GSM, security was a main consideration. GSM authenticates the phone and the user (through a SIM card). Also, the digital nature of the signal provides inherently better security from eavesdroppers, and in addition allows the signal to be enciphered. The ETACS system, is _I believe_ a derivative of the North American AMPS system, which is analog. There are various stories around that security and authentication on AMPS leave a lot to be desired. Not only is it easy to eavesdrop on a cellular conversation, but it is also fairly easy to fake authentication, and fraudulently charge calls to your account. There were some posts earlier about channel pirating on AMPS. Regards, John Scourias http://ccnga.uwaterloo.ca/~jscouria University of Waterloo jscouria@neumann.uwaterloo.ca Waterloo, ON, Canada ------------------------------ From: davethez@netcom.com (Dave) Subject: What is ESF and D4? Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Thu, 23 Feb 1995 18:07:58 GMT When ordering a T1 line for data, the local fiber company wants to know whether I'd like "ESF" or "D4". Could someone please explain what these terms mean? TIA, Dave Z davethez@netcom.com ------------------------------ From: leob@netcom.com Subject: Re: March 7 Bellcore Meeting in DC Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Wed, 22 Feb 1995 01:54:48 GMT > [TELECOM Digest Editor's Note: > This reminds me of the airline a few years ago which misprinted its > schedule book -- thousands of copies distributed -- and gave out the > number of some hapless individual in error instead. When he called to > complain, they told him to change *his* phone number. When they later > found out he was getting rather rude with persistent callers who kept > telling him he was a liar and that they *knew* they had reached the úÿ (continued next message) ÿ@FROM :telecom@delta.eecs.nwu.edu úÿ(Continued from last message) > airline, then the airline tried to sue him for force him to change his > number so that their customers would not be confused. Never once did > it occur to them to correct their own error and reprint their booklet. Apparently the guy was not born American. He made a great mistake, he should have sued the airline as soon as he had started getting annoying phone calls. Leo ------------------------------ From: gshapiro@rain.org (Gary D. Shapiro) Subject: NUtmeg Date: Wed, 22 Feb 1995 01:11:21 +0800 Organization: Committee to Re-Elect George Leroy Tirebiter When I tell people my number is NUtmeg x-xxxx, even the ones old enough to know better say, "huh?". (I have no idea if any 68 prefixes even existed here in 805 when the switch to all digit dialing took place.) Gary D. Shapiro http://www.rain.org/~gshapiro/ ------------------------------ End of TELECOM Digest V15 #119 ******************************