TELECOM Digest Fri, 16 Oct 92 02:00:00 CDT Volume 12 : Issue 784 Index To This Issue: Moderator: Patrick A. Townson Re: LD Transmission Quality Comparison (Steve Elias) Re: LD Transmission Quality Comparison (Andy Sherman) Re: LD Transmission Quality Comparison (John Higdon) Re: Stolen Cell Phone (Craig Heim) Re: Stolen Cell Phone (Olivier M.J. Crepin-Leblond) Re: Stolen Cell Phone (John Gilbert) Re: Stolen Cell Phone (Steve L. Rhoades) Re: Fax Store-and-Forward Service Wanted (Steve Elias) Re: Fax Store-and-Forward Service Wanted (Shrikumar) Fax Mail Service Offered by C&P Telephone (Paul Robinson) ---------------------------------------------------------------------- Subject: Re: LD Transmission Quality Comparison Date: Thu, 15 Oct 92 12:01:10 PDT From: eli@cisco.com andys@internet.sbi.com (Andy Sherman) wrote: > First off, AT&T has had *some* optical fiber in the network for some > time. But the particular medium of digital transmission should matter > not one whit for how to do echo cancellation. The propagation delays > are the same for all terrestrial links. This cannot be correct. Propagation delay depends on media type. The signal propagation speed in fiber is slower than that in coax cable, for example. It must be different for pure copper wire, also. > Besides all that, every now and then somebody posts a throughput test > for the big three carriers, and AT&T almost always wins. I recall Sprint winning a number of these sorts of tests. Lately, in terms of audio quality, the big three are all neck and neck, to my ear. eli ------------------------------ From: andys@internet.sbi.com (Andy Sherman) Subject: Re: LD Transmission Quality Comparison Date: Thu, 15 Oct 92 15:40:10 EDT On Thu, 15 Oct 92 12:01:10 PDT, eli@cisco.com said: > This cannot be correct. Propagation delay depends on media type. The > signal propagation speed in fiber is slower than that in coax cable, for > example. It must be different for pure copper wire, also. By how much? All of these should have propagation speeds in the neighborhood of c. Is the variation enough to change the echo cancellation, or will the trunk length dominate? But I really probably overstated the case. The original assertion was that the presence of fiber in the trunk path made a difference as to whether or not you need echo cancellation. That is false. Any voice circuit, analog or digital, of sufficient length will need echo cancellation to undo the effects of the hybrids at each end. >> Besides all that, every now and then somebody posts a throughput test >> for the big three carriers, and AT&T almost always wins. > I recall Sprint winning a number of these sorts of tests. Lately, > in terms of audio quality, the big three are all neck and neck, to my > ear. Since I and most of the people who call me use the same carrier I have no basis for comparison. Probably they all sound similar unless you have a very good ear. But Higdon's modems, apparently have very good ears, since they know the difference. Andy Sherman Salomon Inc - Unix Systems Support - Rutherford, NJ (201) 896-7018 - andys@sbi.com or asherman@sbi.com "These opinions are mine, all *MINE*. My employer can't have them." ------------------------------ Date: Thu, 15 Oct 92 13:08 PDT From: john@zygot.ati.com (John Higdon) Reply-To: John Higdon Organization: Green Hills and Cows Subject: Re: LD Transmission Quality Comparison On Oct 15 at 15:40, Andy Sherman writes: > Since I and most of the people who call me use the same carrier I have > no basis for comparison. Probably they all sound similar unless you > have a very good ear. But Higdon's modems, apparently have very good > ears, since they know the difference. There is one variable that must be tossed in here. The Bay Area is atypical of other areas of the country. All of the LD carriers (including AT&T) treat this region as some sort of backwater outpost. We were the last to "hear the pin drop" as it were. All are still using some sort of antiquated signaling between POPs and LEC tandems. Example: in the LA area it takes about a half-second for an AT&T call to go through to almost anywhere. Here it takes 8 to 10 seconds. Sprint has regular outages (from my telephone anyway) and offers no explanation. Only recently did AT&T have digital connections between here and other parts of the state. And you could grow old waiting for an MCI call to complete. The point is that the best of the big three is definitely not offered here. Perhaps the reason AT&T comes out ahead is that its low grade crap is better than MCI's or Sprint's low grade crap. John Higdon | P. O. Box 7648 | +1 408 264 4115 | FAX: john@ati.com | San Jose, CA 95150 | 10288 0 700 FOR-A-MOO | +1 408 264 4407 ------------------------------ From: cheim@lectroid.sw.stratus.com (Craig Heim) Subject: Re: Stolen Cell Phone Date: 15 Oct 92 13:26:03 GMT Reply-To: somebody@somehost.edu Organization: Stratus Computer Inc. In article , ccoprfm@prism.gatech.edu (Monte Freeman) writes: > Over this past weekend, someone broke into my car. The two items they > removed (they wanted the whole car, but the alarm system prevented > them from getting that. ) were my OKI 700 cellular phone and a Yaesu > FT-727 dual band hand-held ham radio. > I realize that I'll probably never see the HT again; but I was > wondering what you and/or the rest of the readers think my chances of > getting the phone back are? I called Pactel and told them what had > happened. They turned off service to the phone immediately. > I've heard that there is a database of stolen phone ESNs that the > different service providers keep. What I'm not sure about is if this > database is local to each area, or if it's a nationwide thing ... There are actually two "Nationwide Negative Files". One was formed by GTE Telecommunications Services (GTETS) that services *primarily* the B-band carriers. The other was formed by Appex (now EDS Personal Communications Corporation) that services *primarily* the A-band carriers. There are other smaller services, but these two are the real players. In order for carriers to set up roaming agreements with other carriers, it is a requirement to subscribe to a fraud protection service. GTE offers PVS (Positive Validation Service) and EDS PCC offers PRV (Positive Roamer Validation). Basically, these services connect to each switch and listen for roamer calls. Each roamer ESN is checked against the Nationwide Negative File of invalid numbers. If the number is negative, the verification service sends a command to the switch which handled the call to bar that number. Once a number is barred on the switch, future calls are blocked (or even better, routed to the carriers fraud control department). Note that one successful call was made before the shutdown occurred. It is possible for a bandit to traverse the country making one call at each switch. There is a gateway between GTE and EDS PCC used to keep the Nationwide Negative Files in sync. If an A-band customer roams in a B-band-only area, the validation service may validate the ESN. > If I report a phone stolen here in Atlanta, are the cellular service > providers in Chicago or L.A. likely to know about it? Atlanta will inform the verification service of the stolen phone ESN. That will result in an entry in the Nationwide Negative files. > If the phone does show up "active" on a cell somewhere, is it possible > (or more importantly is it done) to try and track it down? There have been cases where the police/FBI tracked down drug dealers using a device to locate the phone. It is difficult, but possible. Sorry, but I don't think the FBI is going to go after your particular phone. Craig R. Heim |Stratus Computer, Inc. |My opinions are my own, Software Engineer |55 Fairbanks Blvd. |not necessarily are cheim@lectroid.sw.stratus.com |Marlboro, MA 01752-1298 |they Stratus's. ------------------------------ From: c.crepin@ic.ac.uk (Olivier M.J. Crepin-Leblond) Date: Fri, 16 Oct 1992 00:47:21 +0100 Subject: Re: Stolen Cell Phone A friend of mine had his hand-held cell phone stolen two weeks ago. It was grabbed from his hand as he was walking in the street and the thief was running too fast for my friend to catch him. Knowing that he'd never see his phone again, my friend immediately went to a public phone box and called his cellular number. The thief answered and after my friend showered him with insults, they had a brief conversation about getting the phone back otherwise the number would be cut by the phone company. The thief answered that whether with a line or without a line, that phone was worth a lot to him and it was tough luck for my friend before hanging-up. My friend immediately called the cellular company and got the number cut. Sad day. Olivier M.J. Crepin-Leblond, Digital Comms. Section, Elec. Eng. Department Imperial College of Science, Technology and Medicine, London SW7 2BT, UK Internet/Bitnet: - Janet: WARNING: Please send any reply to above addresses, NOT to FROM-field !!! [Moderator's Note: Yes indeed, a sad day, but an all too common scenario these days. Unfortunatly here in the United States, particularly in urban areas, violent crime is growing by leaps and bounds through perverse though popular ways of interpreting our Constitution by some powerful legal organizations here. Someone *tried* to steal my cell phone several months ago; but the way I wrap the strap around my neck and across my shoulders, they'd have to pull my head off to get the phone! :) During the few seconds he was grabbing at me I got my little cannister of Mace (attached to my key ring) from my pocket and gave him a liberal squirt in the eyes and up his nose. That was enough to put him down for the minute or so it took me to hail a cab and (admittedly) leave the scene in a hurry. PAT] ------------------------------ From: johng@comm.mot.com (John Gilbert) Subject: Re: Stolen Cell Phone Organization: Motorola, Inc. Land Mobile Products Sector Date: Thu, 15 Oct 1992 22:25:57 GMT > [Moderator's Note: I think the chances of recovering the phone are > almost zilch. Yes, there is a nationwide negative listing that all the > carriers see. Most likely when the thief discovered the phone would > not work any longer he sold it to some cell phone phreak for ten > dollars ... :( that person will try and modify the ESN or possibly > use the phone for scrap parts, etc. Sorry about your bad luck. PAT] A co-worker of mine had his phone stolen and recovered TWICE! The trick is to make sure that the phone is over the dollar limit that allows it to go on the National Crime Information Computer (NCIC) data base. Since the phone was one of the early (expensive) units it qualified and was returned by the police when it turned up at busts for other offenses. The police seem to be interested in returning phones if incidental to other work, but have no interest in tracking down a $300 phone by itself. I don't know what the minimum dollar limit for property to be posted on NCIC is. John Gilbert johng@ecs.comm.mot.com ------------------------------ From: slr@cco.caltech.edu (Steve L. Rhoades) Subject: Re: Stolen Cell Phone Date: 15 Oct 1992 23:21:05 GMT Organization: California Institute of Technology, Pasadena In article ccoprfm@prism.gatech.edu (Monte Freeman) writes: [Stuff about getting his OKI 700 cellular phone stolen deleted] > I called Pactel and told them what had happened. They turned off > service to the phone immediately. ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ I'm on my third car phone now, the previous two having been stolen. I've always wondered if instead of the provider turning off service to the phone, what about just leaving it on for about a week and see who he/she calls? (Maybe put it on a special class of service so that long distance would be restricted, reducing the loss to the provider.) If the thief were a teenager, chances are he'd be calling all his friends to impress them with his new "toy". Comments? Steve L. Rhoades | Voice: (818) 794-6004 Post Office Box 1000 | Mt. Wilson, Calif 91023 | Internet: slr@cco.caltech.edu [Moderator's Note: Good idea! When two guys picked my pocket on the subway a four years ago (one distracts you while the other gets in your pocket) they got my telco calling card among other things. Although I went back to the station where it happened, found one of the animals and violated his civil liberties by assaulting him in the process of holding him for police who were on the way, the one who actually got my wallet was long gone. I notified IBT the next morning and they turned it off, but when the bill came I skip-traced a few of the phone numbers. I found one place where calls had originated that was a private residence here in the city. I called the number, raised cain and told them off. I also gave that address and phone number to IBT and the police for their report and investigation -- what a joke! :( PAT] ------------------------------ Subject: Re: Fax Store-and-Forward Service Wanted Date: Thu, 15 Oct 92 11:55:22 PDT From: eli@cisco.com If you are talking about a Fax S&F system where you could dial it, enter a phone number, and have it send you a particular fax, boxes which do this are available through Brooktrout Technology, 617 449 4100. It is called their "flashfax" system. Demos are available by calling 617 449 9010. A simpler solution for you might be to get a fax board or external modem for your PC, or use a service similar to the IBT service Patrick described. Also note that the "faxback" type of fax S&F is patented by Brooktrout. Other industry players have refused to pay royalties and instead persist in trying to derail this patent. Apprently yet more patent court action is forthcoming. Brooktrout defeated ATT in the first patent interference suit about the "faxback patent". eli ------------------------------ Date: Thu, 15 Oct 92 23:53:41 -0400 From: shri%unreal@cs.umass.edu Subject: Re: Fax Store-and-Forward Service Wanted Organization: UMass, Amherst, MA 01002 + Temporal Sys & Comp Net, Bombay, India In article ndallen@nyx.cs.du.edu wrote: > I wonder whether someone at Zimbabwe University turns the fax machine > off after 5 p.m. to save electricity, assuming that nobody else in the Perhaps not to save electricity, but to save the (expensive) fax machine. Each minute it is powered on, it is eating operational life and also each minute carries the risk of that surge or spike on the power line that will carry the fax to heavens of delight, from which they sometimes never like to return. And an outage of the fax machine means service charges, probably difficulty in getting spares, and letting that clumsy local repairman put his dirty hands into the machine ... they tend to be an addictive sometimes :-) Also perhaps, everything in the office is turned off anyway in the evening, and by force of habit ... People in the US do tend to forget power line surges, lack of support and competent repair ... and oh, please dont make then sound so cheap ! :-) ;-) ,-) '-) Besides the big carriers, are there any private operators who provide store-fwd fax services ? shrikumar ( shri@legato.cs.umass.edu, shri@iucaa.ernet.in ) ------------------------------ Reply-To: tdarcos@mcimail.com From: FZC@CU.NIH.GOV Date: Thu, 15 Oct 1992 22:17:54 EDT Subject: Fax Mail Service Offered by C&P Telephone In an advertisement on page D13 of today's (10/15) {Washington Post}, C&P Telephone announced that it will offer Bell Atlantic Fax Mailbox service for receiving faxes, in a manner similar to voice mail for messages. I called one of the sales people to get more information about this service, and here are the details based on the questions I could think to ask. Also, their 800 number was answered at 7:55 at night, which was a nice change. The clerk will send me more information about it, but here's what I got so far: Pricing: - No installation charge. However (as noted in a separate paper that I received with my phone bill), the phone company is offering "amnesty" (even if they don't call it that) for service change charges during October whether this service has no installation charge next month is another thing. - $19.95 a month. - No charge to call in and retrieve messages. - If used to send faxes, it's 40c per minute (about 2 pgs/minute) - If a fax is transferred to another fax mailbox, it's 25c untimed (and the system will tell you if the destination is just a phone number or if it's a local fax mailbox) - Will signal a pager or voice mailbox (if it's one of Bell Atlantic's or compatible with it, natch) when you get a fax. Features: - User is assigned a separate telephone number for this service. - User can ask for a specific area code (in this area being 202/301/703), 703 being easier. Sales clerk said he also sold this service to someone in the Philadelphia area, so it might also be available there, too. - If the service is used to send or broadcast faxes, it will do automatic retries. - Incoming documents can be stored. - You can either call in and retrieve received messages from a fax machine, or transfer them someplace else. Capabilities: - You can send a document to a maximum of 15 entries. - You can set up a list of people, and send to the list. - You can place up to 15 entries on a list. - You can set up up to ten lists. (Probably equivalent to the 0-9 buttons on the Touch-Tone pad.) - In theory I suppose you could send a single fax to up to 155 people at once, assuming you used all ten lists plus an additional five numbers. - 50 Page Capacity of "active" documents, (The sales clerk can't say what happens if a single received document is larger than 50 pages.) - Can forward a received document to someplace else. - 25 page capacity of saved documents. Unknown, but will be told to me: - What happens if a single incoming document is longer than 50 pages. - If the answerback given out by the called number can be programmed. Paul Robinson, TDARCOS@MCIMAIL.COM These (uninformed) opinions are exclusively my own, and no one else is (stupid enough to be) responsible for them. ------------------------------ End of TELECOM Digest V12 #784 ******************************