TELECOM Digest Mon, 14 Mar 94 12:26:00 CST Volume 14 : Issue 130 Inside This Issue: Editor: Patrick A. Townson Re: Can I Expect More Than 2400 Baud? (Lars Poulsen) Re: Wireless Internet Connections (jolvan@delphi.com) Re: Sky Radio Service (Joe Harrison) Re: Dialing Numbers at Random (A. Padgett Peterson) No Monthly Fee Cell Phone (Ken Levitt) Ethernet Bandwidth Control Update (Matt Young) Global Telecom Services (Barry Lynch) 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: lars@Eskimo.CPH.CMC.COM (Lars Poulsen) Subject: Re: Can I Expect More Than 2400 Baud? Organization: CMC Network Products, Copenhagen DENMARK Date: Sun, 13 Mar 94 18:24:32 GMT In article wtm@uhura.neoucom.EDU (Bill Mayhew) writes: > I use good quailty Multitech or DSI rack type modems on my end, but > the user community can have almost any sort of equipment. The > Multitechs support 14.4K v.32bis while the DSIs are 9600 v.32 max > modulation. ... users call my system with their modems set to > demand 14.4K rate. Our systems will connect, but the error correction > rate is so high that througput is almost zero. > What puzzles me is that the modems don't fall back when the performacne > gets to be so bad. It would appear that the error correction engine > needs to have some sort of input the the egine that handles modulation. > I am not imtimately familiar with v.32bis / v.42bis specifications, > but some handshaking between the two parts of the modem would seem to > be a most reasonable and logical thing to do. Do the MultiTechs have a way to display the EQM number? (Eye Quality Monitor). This is what feeds back to the retraining mechanism. If you have many bit errors, I should think that your EQM would go south as well. Or is the problem that the modems are retraining, but land back at 14400 when they retrain? > I don't have any current means of measuring it, but what I am > beginning to suspect is that there is phase jitter present on these > lines. Yes, phase jitter can be bad. So can clock slip on digital entrance facilities. Do you by any chance get these lines delivered on a channel bank? Is there a SLC-96 nearby? Are these hospitals all part of a big Centrex or do they use tie lines between sites? If so, there is likely to be one or more DACS involved, which could be misconfigured and cause clock slip. > The nature of the problems I have doesn't seem to depend on the length > of the circuit or number of central offices involved. As you would expect if the problem is at the receiving end. If the phone company cannot fix the real problem, cap the MultiTechs at 9600. Lars Poulsen Internet E-mail: lars@CMC.COM CMC Network Products Phone: (011-) +45-31 49 81 08 Hvidovre Strandvej 72 B Telefax: +45-31 49 83 08 DK-2650 Hvidovre, DENMARK Internets: designed and built while you wait ------------------------------ From: jolvan@delphi.com Subject: Re: Wireless Internet Connections Date: Mon, 14 Mar 94 01:32:44 -0500 Organization: Delphi (info@delphi.com email, 800-695-4005 voice) You may be thinking of Planet Connect's system; it sends newsgroups and tons of other stuff through a ku or c band sat. There's coverage of it in the January issue of {Boardwatch} or call them 615-623-8751 in Newport, Tennessee. ------------------------------ Date: Mon, 14 Mar 1994 10:42:41 +0000 From: J.Harrison@bra0112.wins.icl.co.uk Subject: Re: Sky Radio Service spectrumshow@genie.geis.com wrote: > I read that a new audio service is being offered to airliners in > flight. It is called Skyradio and is delivered via satellite. ... Well I get a station named Sky Radio and it's delivered via satellite. The Astra transponder carries a variety of TV channels (mostly crap) but there is this one radio station as well. You can apparently get a receiver that will bring it into a car, and I heard of somebody who listened to it in stereo all the way on some 1500 mile drive across Europe. It's well worth a listen if you're aged over about 30 and like a nice relaxed style of music. If you don't mind the commercials and news in Dutch that is. Joe ICL Ltd. Bracknell Berkshire RG12 8SN UK (+44-344-473424) J.Harrison@bra0112.wins.icl.co.uk S=Harrison/I=J/OU1=bra0112/O=icl/P=icl/A=gold 400/C=GB ------------------------------ Date: Mon, 14 Mar 94 07:56:09 -0500 From: padgett@tccslr.dnet.mmc.com (A. Padgett Peterson) Subject: Re: Dialing Numbers at Random > In article wrote: >> Is there a shareware program or commercial program available that can >> dial randomly within a given area code and when it comes across a fax >> machine log that fax number into a database. If anyone has any >> pointers I would appreciate it. (negative replies ommitted) Though the concept of checking an entire area code indicates less-than- desirable motives, the concept of "demon dialing" is not necessarily bad in itself so long as the domain is confined to a wholly-owned one. My employer expects me o safeguard our systems and as a reqular part of "walking around and rattling the doorknobs" I use war dialers to test for access points however I confine such activities to our wholly-owned exchanges (five digit dialing). Invariably, in a population as large and computer-intensive as ours, individuals are tempted to add a modem for convenience despite the availability of modem pools (possibly due to cost - one-time-password tokens still cost about $50.00 each - what we need is the ability to put a token into PC software - of course what we really need is full session encryption). Since my charge is "securing the perimeter", one of the best ways is to periodically test it and generally I use the same techniques that intruders do. The only difference is that when I find a vulnerable point, the owner gets a friendly memo instead of a writeup in a crackerzine. Of course, the first time I looked, many exceptions were found. Since then the rate has been admirably low, once again proving that my job is best done if it needs to do nothing. I have the same opinion of sniffers. Guess the biggest difference between intruders and myself is that everyone here knows what I do -- was one of *my* requirements 8*). Warmly, Padgett ------------------------------ Date: Sun, 13 Mar 94 12:20:38 EST From: levitt@zorro9.fidonet.org (Ken Levitt) Subject: No Monthly Fee Cell Phone There is a company in Massachusetts (Lindsay Communications 800-370-4445) offering Cell Phone service for $35 per year with no monthly fee and no activation fee. They advertise this service as a way to deal with road emergencies. They are marketing this service under the trade name of HELPTEL. Plan 1: 1. They sell you a cell phone for $179 that has no dial pad. It plugs into a cigarette lighter socket in your car. You can also purchase an optional battery pack. 2. You press the "Help" button on the phone and are connected to their "Emergency Response Center". You give them your PIN and they get a list of numbers you have given them on their computer screen. You can select one of the predefined calls or you can ask them to dial any other number for you. 3. I don't know if it is possible for anyone to call you. 4. You pay $3.50 per minute of air time. Plan 2: 1. You already own a cell phone. 2. You pay them $45 for a "one-time" programming fee. 3. You can make and receive calls normally at $2.50 per minute. 4. You can call their "Emergency Response Center" for $3.50 per minute. This may be a good plan for someone like me who owns a cell phone and only makes an average of one or two short calls per month. I currently pay about $20 per month in fees to Nynex. Ken Levitt - On FidoNet gateway node 1:16/390 UUCP: zorro9!levitt INTERNET: levitt@zorro9.fidonet.org or levitt%zorro9.uucp@talcott.harvard.edu ------------------------------ From: kyma@netcom.com (Matt Young) Subject: Ethernet Bandwidth Control Update Organization: NETCOM On-line Communication Services (408 241-9760 guest) A couple of advances on the front for defining a bandwidth control protocol for ethernet, in support of voice calls. I have called up four ethernet vendors and discovered that two of them are at least discussing a bandwidth control protocol in their marketing departments. IMHO, I conclude that the companies are at least satisfied that a technology exists. The ftp reports on shared media switches cited by posters on this newsgroup helped the cause, thanks. To help speed matters, I dropped a thread in some of the other dcom related newsgroups to elicit user response. Some robust discussion of the issue among users is a great accelerator for these projects. I had trouble finding a suitable name for bandwidth controlled circuits over ethernet. "Leased line equivalents" is the least benign term but very ackward to use. I have selected the term "variable length cells" (roughly 60-600 bytes long), which is a contradiction in terms. Normally the next step will be the formation of a consortium for bandwidth control over ethernet. The default consortium leader will be Intel, but that probably doesn't do justice to the academic groups who have pioneered ethernet based cell transmission. I would suggest an RFC from any research group interested in keeping their interests protected. Finally, I have located at least one major developer to use the capability. The process seems to be on schedule here, investors are responding with start up funds. At least two new companies, one ATM related, will be looking at potential products. End users would have the choice of paying a premium to buy bandwidth controlled adapter cards to replace all of the adapter cards within an ethernet segment. Then from that segment any desktop could make a standard packet voice or packet video call through an external switched network or make a local bandwidth controlled call to another ethernet station also on a bandwidth controlled ethernet segment. All other traffic and protocols on the ethernet would operate normally, except that a maximum frame size would be imposed during periods in which delay controlled calls are active. The maximum packet size would be on the order of 600 bytes. I have identified a control protocol which allows bandwidth control, which we can discuss. However mainly I need to identify an interested group of end users, sufficiently large to interest the major adapter card vendors. If users desire to use their ethernet PCs for standard voice communications, with full integration into the telephone and cell relay networks, then please make yourself known to me or to this newsgroup. Thank you, Matt Young kyma@netcom.com ------------------------------ From: Barry Lynch Subject: Global Telecom Services Date: Sun, 13 Mar 94 23:52:45 -0500 Organization: Delphi (info@delphi.com email, 800-695-4005 voice) I am writing a book for a publisher in the US on the Global Product offerings that are being implemented by the various strategic alliances that have been announced to date (i.e. WorldPartners, MCI/BT et al). I would like to include an assessment of the state of competition in the various worldwide markets, as well as user requirements for markets where competition has either just started, or is planned. Any *war stories* or comments would be greatly appreciated concerning foreign (non-US) markets. Please e-mail me at the address below. Barry Lynch - President Lynch Resources barrylynch@delphi.com ------------------------------ End of TELECOM Digest V14 #130 ****************************** ------------------------------------------------------------------------------- Downloaded From P-80 International Information Systems 304-744-2253