TELECOM Digest Fri, 13 May 94 11:44:30 CDT Volume 14 : Issue 222 Inside This Issue: Editor: Patrick A. Townson Re: Can Residential Voltage (?) Drop? (balcroan@netcom.com) Re: Graceful Degradation (Bill Tighe) Re: What is the Mercury Button? (Neil Watson) Re: Government Regulates Number of Modem Redial Attempts? (Kaita Seikku) Re: Government Regulates Number of Modem Redial Attempts? (Chip Sharp) Re: GSM and Airbags (David Breneman) Re: 3270 Emulation (Jack Hamilton) Re: 3270 Emulation (William M. Eldridge) Re: Meeks Defense Fund (Stephen Cohoon) Re: Searching For a Specific Telephone (Steve Cogorno) Re: Delrina Fax MailBox Retrieval and Class 2 Modems (Jack Bzoza) Re: Cellular Call Forwarding (John Musselman) Digital MSK Modem Questions (christos@kuhub.cc.ukans.edu) Request For an FTP Site For X509 (Pat Worden) 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: balcroan@netcom.com (Butch lcroan/.nameBalcroan Lilli) Subject: Re: Can Residential Voltage (?) Drop? Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Fri, 13 May 1994 07:29:25 GMT balcroan@netcom.com wrote: >>> Is voltage somehow involved in "ringing" so that a decrease would >>> cause to small a *something* for devices like modem cards and handsets >>> to respond to? Where does this happen, and what's the fix? >> Ringing is a low-frequency AC signal applied to the line (Typically 90 >> volts at 20 Hertz). Tell the repair desk that "ringing voltage is not >> being applied". They will likely find the problem to be the line >> equipment (printed circuit card in modern exchanges) feeding your >> line. > If the above call to the local TELCO doesn't work please submit > private e-mail and I will give you the answer you can then decide if > you want to make it public after it is tried ... BTW if it is what I > suspect it is be prepared for the other line to have the same problem > shortly .... > [TELECOM Digest Editor's Note: Do tell us more! PAT] I am not sure all problems mentioned above relate to this little problem about to be mentioned ... but always be aware there is the possibility of a "PAIR-GAIN DEVICE" or "SUBCRIBER CARRIER" between the voltages the CO generates on analog tip and ring pair and the analog tip and ring pair that is attached to the phones in question. I would also like to caution regarding all phones as there is no way the phones you get free from {TIME & LIFE} for a subscription is as good as the NTI, AT&T, GTE or other phones purchased at the Phone-Mart in the mall. 1.) PAIR GAIN devices are of various generations and some work better than others at ringing more phones than one. The voltage and current can both be in question. 2.) The capacitance can vary greatly between a "cheapie" phone and a more expensive phone. There is also the resistance between the T & R that can cause a shorting or shunting of a AC signal such as the ringing voltage. This can also cause the phone to ring once and then stop because of the momentary short cause by the insulation breakdown cause the 20 milliamp current caused by a off hook condition. This is read by the CO as an answer! Then the ringing stops and so does the current flow and ooooppps no answer! This was found to be the case in a state that will remained unnamed ... we (NTI) had a engineer camped out at the customer site wait for the problem to be reproduced and as he was watching TV on came an advertisement ... he went to the store in the mall that was giving away one of these phones for free just for coming down ... well it was tested next day and the above was found. They had been giving them away all month long. This was the problem that had went to a VP level to find ... oh BTW a Automatic Line Insulation Test (which had been requested at least three times by NTI but telco said NO IT WOULD BE A WASTE OF TIME) found several of these "$3.95" phones ... not a defective piece of software as the telco had suggested. Butch email balcroan@netcom.com ------------------------------ From: bill@noller.com (Bill Tighe) Subject: Re: Graceful Degradation Date: 13 May 94 11:24:24 GMT levin@1.121.159.165.in-addr.arpa (jerry levin @ Trident Data Systems) wrote: > Can anyone explain to me what is meant by graceful degradation when > referring to a data bus? Computer redundancy can be implemented in many ways and the method used depends on the demands of the application. "Graceful degredation" refers to a redundancy method used for applications where it is advantageous to keep all resources on line when they are functional. As modules fail they are taken off line and the total computer power is reduced. Thus computer power "gracefully degrades" and error recovery techniques hide the failure from the users. Sequoia uses this method for on line transaction processing. Computer modules, 68xxx I beleive, run in parallel and if one fails, the load is shifted to the remaining units. Users may notice an increase in response time but they still have a working system. Since no expensive modules are sitting idle, the customer gets high performance and reliability for the lowest possible cost. Some applications such as aircraft control cannot work with a degraded computer so full idle backup units must be used. Some aircraft systems have triple redundancy, two backups for each working computer. Expensive but necessary. Bill Tighe Email: bill@noller.com Phone: 707-778-0571 FAX: 707-778-0235 PCMCIA; People Can't Memorize Computer Industry Acronyms ------------------------------ From: nwatson@Aspect.COM (Neil Watson) Subject: Re: What is the Mercury Button? Date: Fri, 13 May 1994 13:13:11 GMT In article johnper@bunsen.rosemount.com (John Perkins) writes: >>> Detailed question about Mercury button deleted. The Mercury button is a slightly special "one press" memory button. To access Mercury you need to dial their access code (131 for the 2200 service), wait for dialtone again (high pitched noise) then dial a 10 digit PIN (for identification) followed at last by the called number. The additional complexity is that the Access code will have to be dialled in whichever mode your BT exchange will support (ie it may have to be pulse) and the rest of the number after the Mercury DT has to be DTMF (tone). Thus a phone that can switch between pulse and tone dialling mid-way through a memory dial is a requirement. If you're in a tone-dialling area (which is most exchanges now), then this isn't an issue. Other things that go into the "suitability" for use on Hg are the ability to sequentially dial memories (to dial a certain relative we dial mem 1 followed by mem 5) and the ability to dial other numbers while the phone is still dialling the memory. Also your "last number redial" register needs to be 24 digits or so! From this information you will realize that it is not strictly necessary to have a phone with the fancy blue button to use Mercury. I personally have a normal phone that I've programmed mem 1 to do the Mercury predial and it works just fine. Then again a single, clearly identified button to identify the long distance carrier is simpler. Another thing to take into account is Mercury's recently announced 132 service which uses ANI/CLI to determine the authenticity of the caller. To use this you only need dial 132 followed by the called number. Unfortunately it requires a modern BT exchange and so isn't available everywhere that can access Mercury yet ... (yes, I know CLI isn't available to subscribers in the UK yet, but LD carriers are a different matter.) > They have a perfectly good BT "Tribune" phone set that has some > special attachments for the hearing impaired, but are under the > impression that they can't use it if they want to use Mercury. (I have > a feeling that they don't really need the Mercury phone set at all.) I don't know about the Tribune -- many of the BT sourced phones didn't have sufficient memory versatility to do the job for a Mercury Blue button, but may well have enough for 132 access. Good luck, Neil ------------------------------ From: spk@proffa.cc.tut.fi (Kaita Seikku) Subject: Re: Government Regulates Number of Modem Redial Atttempts? Date: 13 May 1994 07:12:42 GMT Organization: Tampere University of Technology, Computing Centre TELECOM Digest Editor noted: > ... Some people, you see, leave the speaker turned off all the time > and as a result don't even realize they are connecting to a live > person in errror instead of another modem. I would rather have seen a > rule saying that if voice was detected instead of carrier, the speaker > would automatically turn on ... What if the modems were equipped with DTMF receive capability, and then the software while waiting for the connection to establish, would fall back if any DTMF was detected? (Then it would just be tough to those people who would not know about the DTMF implementation ...) Or actually, my real opinion : As the new features are programmed into the switching software, there should be a new command (like *21*redirection) to ignore calls from the number that last called me (which would be a great help against those "%$&/()= phone sales persons, too). Of course thers's a problem in this, too, since your (B-subscriber's) switch does not always get the A-subscriber number complete. (I mean the old technics, not the deliberate disabling of caller ID, there should be a command to ignore ALL calls that have been originated with caller-ID disabled). internet : spk@proffa.cc.tut.fi answering machine->pager : +358 -43 498 0297 real life: Seikku P. Kaita phone (or FAX) : +358 -31 265 6865 visit at : Saastajankuja 4b32 TAMPERE On The Air : OH3NYB ^^ ^ ^ ..these four a's should have double dots above them, since they are front vowels (as in word 'that'). Isn't it a pitty that in English the word GHOTI can be pronounced like word FISH. [TELECOM Digest Editor's Note: Actually the feature you suggest has been implemented. Call Screening allows either the entry of a number from which the subscriber no longer wishes to receive calls or if that number is not known (because the calling party blocked his ID) an entry for 'last call recieved' in which case the CO will note the number and block further calls from it to the recipient even though the recipient is not given the number in an effort to avoid violating the privacy of the caller. Here in Illinois Bell territory, we use *60 to add/delete numbers to our Call Screening directory. If thus screened, the calling party gets an intercept message saying the called party 'is not receiving calls at this time.' It does not say 'is not receiving calls from *you*' ... just 'not receiving calls'. Of course the calling party can go to another telephone if they wish, but few people bother; they simply take the hint and don't call back. PAT] ------------------------------ Date: Fri, 13 May 94 08:22:29 EDT From: hhs@teleoscom.com (Chip Sharp) Subject: Re: Government Regulates Modem Redial Attempts FYI, Most countries have a redial limit much less than the FCC's current 15 redial attempts. For example, Japan has a limit of 2 redials. Some countries relax that limit somewhat if the redials are spaced a certain amount of time apart. You have to check with each country's regulations to determine that time. One interesting question is: Does the redial limit apply to ISDN terminals or just to PSTN modems? If it does apply to ISDN, does it apply only to Speech and 3.1 kHz Audio (Voice-band data) calls or does it also apply to 56/64 kbit/s data calls and multirate (i.e., n x 64 kbit/s) calls? Hascall H. Sharp Teleos Communications, Inc. System Engineering 2 Meridian Road Eatontown, NJ 07724 USA voice: +1 908 544 6424 fax: +1 908 544 9890 email: hhs@teleoscom.com ------------------------------ From: daveb@jaws (David Breneman) Subject: Re: GSM and Airbags Date: 12 May 94 22:43:59 GMT Organization: Digital Systems International, Redmond WA Ben Burch (Ben_Burch@wes.mot.com) wrote: > In article Bill Tighe, bill@noller.com > writes: >> ... Some Audis in the early 80s would respond to RF by having the >> cruise control go to full throttle while the ABS disabled the brakes! > Ah, Bill, do you have any pointers to documentation on this? I > believe that the causes of the (fatal) Audi "unintended acceleration" > events have always been in considerable doubt. Audi claims that it is > "driver error", since one can always override the throttle with the > brakes, but since I have seen other cars have a simultaneous brake and > throttle failure, I have always wondered. This story is indeed bogus. The only way ABS could "disable" the brakes would be if it took out a wrench and unbolted the pedal. The infamous unintended accelleration legend is entirely the result of people pressing down on the gas when they should have been using the brake. At least it allowd some people to pick up some really nice cars cheap when the value of Audis dropped after these scare stories circulated. David Breneman Email: daveb@jaws.engineering.dgtl.com System Administrator, Voice: 206 881-7544 Fax: 206 556-8033 Product Development Platforms Digital Systems International, Inc. Redmond, Washington, U. S. o' A. ------------------------------ From: jfh@netcom.com (Jack Hamilton) Subject: Re: 3270 Emulation Organization: NETCOM On-line Communication Services (408 261-4700 guest) Date: Thu, 12 May 1994 23:00:27 GMT ssi@winternet.com (Stillwater Systems) wrote: > I'm looking for a good Shareware 3270 Emulator for Windows. I do a > great deal of work in the VAX/VMS environment and use WRQ's Reflection > 2 for Windows, however, this is not suited for the IBM mainframe > environment. If you know of any 3270 Emulators for Windows, could you > please provide me with the information I need to obtain them. Your question really doesn't give enough information. What are your options for connecting to the mainframe? If you can connect through SLIP or PPP or something else that provides Winsock services, there is at least one tn3270 program available via ftp from sunsite.unc.edu. I don't remember the exact path, put it's comething like micro/pc/winsock. There are also several books on the market which include the dial-in only version of NetManage's Chameleon v3. It's not shareware, but it's only $25 or so. Jack Hamilton Postal: POB 281107 SF CA 94128 USA jfh@netcom.com Packet: kd6ttl@w6pw.#nocal.ca.us.na ------------------------------ From: bill@LIFESCI.UCLA.EDU (William M. Eldridge) Subject: Re: 3270 Emulation Date: 12 May 1994 19:42:01 -0700 Organization: UCLA Cognitive Science Research Program > I'm looking for a good Shareware 3270 Emulator for Windows. I do a > great deal of work in the VAX/VMS environment and use WRQ's Reflection > 2 for Windows, however, this is not suited for the IBM mainframe > environment. If you know of any 3270 Emulators for Windows, could you > please provide me with the information I need to obtain them. We've had good luck with McGill's TCP3270. It's pretty cheap as well (don't remember the per machine cost, but a site license is something like $500). Contact Pierre Goyette (pierre@cc.mcgille.ca). (Program requires Lan Workplace or Winsock) Bill Eldridge bill@lifesci.ucla.edu 310-206-3960 (3987 fax) ------------------------------ Date: Fri, 13 May 94 11:30:12 -0500 From: cohoon@cse.uta.edu (Stephen Cohoon) Subject: Re: Meeks Defense Fund Organization: Computer Science Engineering at the Univ of Texas at Arlington In article TELECOM Digest Editor notes: [Details of net.libel.defendent deleted] > [TELECOM Digest Editor's Note: ... [Moderator's legitimizing deleted] > The law says no libeling, period. Big corporation, little company, > single individual, no matter. Newspapers have a little more freedom in > this respect and all of us have a bit more freedom where politicians > and 'public figures' are concerned, but no one can deliberatly libel > another without paying the consequences. [More good points from Moderator deleted] > Inform the net of your situation and plead for funds, but do not give > us the bit about how the net is so different and special. > Now I repeat: it seems a worthy cause otherwise. Lots of netters have > come to my rescue in the past and I am glad to bring this latest need > to the attention of our generous readers. PAT] This type of request has been showing up more frequently recently. Someone finds themself in legal trouble and tries to rally the "net" behind their cause. Pat's statements are exactly on point. If you want the support of the net community then state your case. Don't just appeal to our sympathy based on our possession of a modem. Did Meeks make libelous statements or not? What facts support his claim that he is innocent? Why should I believe that the people whose names appear in this posting do in fact support his cause? In my opinion this request is suspect at best. I believe in the value of the net and moderated digests such as this one. However, like all the other forms of media, there are standards of journalism that must be adhered to or the value of the media will disappear. Just my opinions, Stephen Cohoon cohoon@cse.u ta.ed [TELECOM Digest Editor's Note: Well, if the names which appeared in the article were there with the permission of the people they represent (and I doubt the author just picked the names out of the ether and attached them without permission) then I have no questions about the authenticity of the appeal. Those are all respected net citizens. But as you stated, I wish they would realize that merely having a modem and being connected to the Internet is no longer -- if it ever was -- a good enough common denominator. Merely publishing an e-journal or maintaining a mailing list is not a tie that binds either. If anything, the tie that binds e-journal editors/publishers/list maintainers ought to be a desire to be treated on a par with the traditional print media, and that includes the 'right' to get sued once in a while when you flap your jaw at the wrong time, or when someone gets bent out of shape and claims that you did. And our objective of course must be to defeat such suits when they arise, thus my printing of the appeal. Still, some people are their own worst enemies; that is particularly true on the net. PAT] ------------------------------ From: cogorno@netcom.com (Steve Cogorno) Subject: Re: Searching For a Specific Telephone Date: Fri, 13 May 1994 10:20:32 PDT Said by: Karim.Farrag > For quite a while now I'am searching for a specific telephone probably > manufactured by AT&T.Specific features: narrow receiver, the speech > unit of the receiver is bent almost 90 degrees; the receiver is shaped > like an L , wire phone, mostly seen in black colour.I suppose it most > be a very common model in the US , because I saw in many different > movies (ex. In the Line of Fire ,Last Action Hero, etc.). Unfortunaly > AT&T here in Europe wasn't as cooperative as I thought. Now I am > hoping that someone knows which phone I am talking about (telephone > manufactor, model number) or maybe the main address of AT&T in the > US. Many thanks in advance. It sounds like you are referring to the MERLIN/System 25,75, etc Voice Terminals. You will not be able to use these without a Control Unit, which will cost more than $1500 in most cases. The phones themselves range from $250-500 depending on the size. Steve cogorno@netcom.com #608 Merrill * 200 McLaughlin Drive * Santa Cruz, CA 95064-1015 ------------------------------ From: Jack Bzoza Subject: Delrina Fax MailBox Retrieval & Class 2 modems Date: Thu, 12 May 1994 19:15:00 -0400 In a previous message to Jack Bzoza, Clarence Doid said: >> WinFax 4.0 _requires_ a class 1 Faxmodem for mailbox retrieval. >> The Class 2 faxmodem that I have cannot be used. To which Jack Bzoza replied: > Yes. you're right. That is a technical limitation of the hardware as > 1t elates to the fax protocols. You also need a computer capable of > running Windows. I guess you won't be able to use it until you spring > for $100 for a new modem. BUT JACK BZOZA WAS WRONG !! Catherine Murphy, of Delrina's Quality Assurance department advises: "You may be referring to old information because for Fax MailBox retreival using WinFax 4.0 Class 2 modems can be used. So can CAS modem. Only the remote retrieval is limited only to Class 1 modems. When the UK version of WinFax with MailBoxes is available it will be limited only to Class 1 modems. I hope this information is useful." Sorry for any confusion I may have caused. ------------------------------ From: jcm@frank.nccom.com (John Musselman) Subject: Re: Cellular Call Forwarding Date: 13 May 1994 04:54:27 -0700 Organization: North County Communications, San Diego, California Mark W. Earle (mwearle@netcom.com) wrote: > It should be noted that some roaming costs, though, have dropped in > the last five months. The per minute charge is lower, and the daily > fee is not charged. But this is not "universal" you still have to > check where you intend to roam with the carrier and find out the up to > the minute info. Of course the roam rate and daily fees (or lack > thereof) influence greately how and how much the phone is used while > out of town. Roaming is still a ridiculous cost! Another thing I stress about: I am a US West Cellular customer in San Diego. I travel to Phoenix often to visit friends and family. I wanted to get a Phoenix number to avoid roaming and take advantage of my dual-nam phone. It was cheaper to go with Bell Atlantic in Phoenix than it was US West. US West could have had 1 1/2 times the business from me, however different markets are differently priced. For people like myself, I would like to see cellular carriers that are in multiple cities offer a bonus to people who have multiple numbers in multiple cities ... Just my thoughts, jcm@nccom.com -John C. Musselman -Software Developer/System Analyst ------------------------------ From: christos@kuhub.cc.ukans.edu Subject: Digital MSK Modem Questions Date: 12 May 94 16:21:08 CDT Organization: University of Kansas Academic Computing Services Hello there, I have some questions about MSK bit error rate performance. Going through literature and papers I have encountered a number of MSK implemenatations and different points of view. I have the following questions: 1. Do all MSK implemenatations have the same performance? Serial MSK, Parallel MSK, Fast MSK etc? 2. Parallel MSK is an OQPSK with half sine wave shaping the transmitted pulse. Therefore, the Pe (Probability of Error) for MSK is the same as that for QPSK and BPSK (since Pe for BPSK and QPSK are the same). MSK can also be viewed as orthogonal BFSK. However, the Pe for orthogonal BFSK is Q(sqrt(Eb/No)) where the Pe for BPSK is Q(sqrt(2Eb/No)). Thus, we have two different types of MSK giving different performances. Is the above correct? 3. Also, in the literature it is mentioned that Serial MSK has a better performance at higher bit rates? By performance do we mean Pe? What is the reason for that? Does serial MSK has the same theoretical performance as the parallel MSK? 4. I have seen in a book, I cannot recall which book was that, that the PSD of a stationary process tells us about the probability of occurence of each frequency component. In other words, if the PSD is large at 1kHz for example then we can say that there is high probability that the frequency component at 10kHz will occur. Is that true? The reason that the PSD is a statistical function it should have some statistical interpretation. I would very much appreciate your response. Thanks in advance, Chris Pleaase e-mail: christos@kuhub.cc.ukans.edu ------------------------------ From: pworden@weber.ucsd.edu (Pat Worden) Subject: Request For an FTP Site For X509 Date: 12 May 1994 21:31:35 GMT Organization: U.C.S.D. Department of Communication Can anyone send me a name for the site to download X509 protocol descriptions? Please send any replies to me a benson@acdca.itt.com. I am borrowing my wife's account due to a network screwup on my compnay's machine.) Thanks, Peter Benson ------------------------------ End of TELECOM Digest V14 #222 ****************************** -------------------------------------------------------------------------------