TELECOM Digest Thu, 16 Dec 93 02:17:00 CST Volume 13 : Issue 821 Inside This Issue: Moderator: Patrick A. Townson When is the BFI Flag Set by the Radio Subsystem in GSM? (Vartan Narinian) Calling Cards and Privately Owned Pay Phones (Javier Henderson) Portable Satellite Phone System (Paul Coladonato) Digital Phones of the Past (Bob Smith) Check From AT&T: Here's What to Do! (Robert A. Book) Re: New 411 System in Atlanta (Charles Hoequist) Re: Double Hunt Group - Possible? (Danny Burstein) Re: Ethernet Over Laser Link (John R. Levine) Re: Computer Cannot Receive From Modem (Arthur Rubin) Re: Computer Cannot Receive From Modem (Jay Hennigan) Re: NPA 905 Not Universally Recognized (Mark Brader) Re: A New Love Story (Solution) (Dror Lubin via Mark Brader) 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. 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 and redistribution/cross-posting of articles herein to news groups such as those distributed via 'Usenet' is prohibited unless permission is ob- tained in writing. This does not apply to *authorized* redistribution lists and sites who have agreed to distribute the Digest. All cross- postings or other redistributions must include the full Digest intact and unedited. 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. You can reach us by snail mail at Post Office Box 1570, Chicago, IL 60690 or Fax at 1-708-329-0572. ---------------------------------------------------------------------- Date: Wed, 15 Dec 93 18:43:18 GMT Subject: When is the BFI Flag Set by the Radio Subsystem in GSM? Organization: Imperial College of Science, Technology and Medicine From: v.narinian@imperial.ac.uk (Vartan Narinian) Hello experts, Could someone tell me when the BFI (Bad Frame Indication) flag is set by the GSM radio subsystem? This is in GSM 05.05 which, unfortunately, I don't have. I'm mostly interested about the Speech traffic case, because this flag is used in the substitution and muting of lost frames section (06.11). My understanding is that the BFI is set when, after deinterleaving and decoding, the CRC on the 50 class 1 bits indicates that there are errors in those bits. However, I'm not sure about this and would like someone to confirm it, if that's possible. Thanks, Vartan Narinian Electrical Engineering Department Imperial College, London ------------------------------ From: henderson@mlnaxp.mln.com Subject: Calling Cards and Privately Owned Pay Phones Date: 15 Dec 93 11:44:54 PST Organization: Medical Laboratory Network; Ventura, CA Hello, Some time ago I posted about the problems I had using my Orange calling card with some privately owned pay phones. Basically, some phones appeared to be programmed so they would drop the connection after a certain number of numbers have been punched. When I complained to one of the operators, I was told that it was to help law enforcement in the war against drugs (yeah, right ... more like force you to use their operator $ervice$). So I called one of the operators today from a payphone that was giving me that trouble. This time I told her "I had problems using the voicemail system at work". She suggested to push the keys slower and to leave a longer pause each two or three keystrokes. It worked. I dialed the target number leaving three second pauses between the phone number and the calling card number and waited five seconds before pushing in the PIN. Hope it works elsewhere. Javier Henderson henderson@mlnaxp.mln.com [Moderator's Note: Interesting theory. If anyone else tries this and has success (from a phone at which previously they were unable to continue pressing buttons) please write and let us know. PAT] ------------------------------ From: pc@hknet.hk.net (Paul Coladonato) Subject: Portable Satellite Phone System Organization: Hong Kong Internet & Gateway Services Ltd. Date: Thu, 16 Dec 1993 06:44:08 GMT Hello all, Does anyone know if it is currently possible to have a portable satellite phone system useable anywhere in the world? That would allow reliable modem communications from areas poorly served by land lines? What companies provide this equipment/services? Thanks, Paul ------------------------------ From: bob@sed.csc.com (Bob Smith) Subject: Digital Phones of the Past Organization: Computer Sciences Corporation Date: Wed, 15 Dec 1993 15:32:06 GMT The term digital phone today seems to be interchangable with ISDN phone. However, I seem to recall a time in the past (70s) when a digital phone had a bunch of digital circuitry in it and talked to a pre-ISDN digital hook up. My memory may be failing but I seem to recall DTMF digitized voice and Bell's DSDS being tied to gether. Please help staighten out my graying brain!!! Am I on track or is this an erroneous recollection of an old {Popular Science} article? Thanks, bob ------------------------------ Subject: Check From AT&T: Here's What to Do! Date: Wed, 15 Dec 93 23:56:17 CST From: rbook@rice.edu (Robert A. Book) I got one of those $50 checks from AT&T, and (separately) a $20 "credit voucher" good toward payment of my AT&T Unversal MasterCard bill with the same conditions (sign it and get switched to AT&T). I found a perfectly legal, ethical way to get the face value of the the voucher, the check, and then some. My primary carrier is MCI. I called MCI and told them what I had received. For the "credit voucher," they gave me a credit to my account for the face value ($20), in exchange for my sending them the voucher. For the check, the told me to write "Void" across the check, and send it to them, in exchange for which they would send me something called a "Customer Appreciation Bond" with a face value equal to the value of the check ($50). I could either send this check back immediately for a $50 credit, or hold on to it, in which case it would *gain* $5 per month every month for up to one year. I could exchange it at any time for the total value, which after a year would be $110. Gee, these guys are getting desparate! :-) NOTE: I got the idea to call MCI (which, I admit, I should have thought of myself) from another posting to this Digest in which someone with Sprint called them, and they exchanged the check for face-value credit. So ... ***** THE MORAL OF THE STORY ***** If you receive a check or similar instrument, negotiable on the condition that you change carriers, and you don't want to change, call you current carrier. They will probably match, and in the case of MCI, beat the offer, to keep you as a customer. This is a legal, ethical, and risk-free way to redeem these offers without switching carriers. Robert Book rbook@rice.edu ------------------------------ Date: Wed, 15 Dec 1993 12:20:00 From: Charles Hoequist Subject: Re: New 411 System in Atlanta In the Digest Issue 772 Les Reeves requested information about the new 411 service in the Atlanta area (it's also now in service in a couple of other areas in Georgia). Here are some details. The service is called ADAS (Automated D.A. Service). It does not use any voice recognition, just store and and playback. Its virtues are (1) saves telco money, because the front end of the call (querying city and listing) is automated and so not occupying an operator position; (2) saves operators from having to say, "This is , what city?" 1000-1200 times a shift (which is the average range). (3) increases throughput by discouraging callers who either just want to abuse an operator or want something other than DA (I listened to a couple of hours of recordings from an operator position, and I was amazed at the variety of information requests that came in). As Les noted, the application prompts for city name and listing name, then (if everything works right), a subscriber hears the Automatic Response Unit giving the desired number. From the operator's perspective, there is first a special tone announcing the arrival of an ADAS call, then the recorded city name, then the recorded listing name (i.e. what the subscriber said in response to the prompts). If the recordings aren't satisfactory, the operator opens a call path to the subscriber and collects the information, but this is infrequent. Normally, the operator does the database search and hands the call off to the ARU. Hope this helps. Charles Hoequist, Jr. | Internet: hoequist@bnr.ca BNR, Inc. | voice: 919-991-8642 PO Box 13478 | fax: 919-991-8008 Research Triangle Park NC 27709-3478 ------------------------------ From: dannyb@panix.com (danny burstein) Subject: Re: Double Hunt Group - Possible? Date: 16 Dec 1993 01:38:42 -0500 Organization: PANIX Public Access Internet and Unix, NYC While Pat explained the process, he was a bit, ahem, wordy. So to clear this up in just a few paragraphs: Problem: Customer has a mix of computer modems and lines, wants to rearrange them so that hi-speed callers (who presumably pay extra) get high speed modems, but low speed folk get the low speed. He also wants teh high speed folk to kcik into the low speed modems when all high speed are busy. Solution: (Bear in mind that the numbers you get will -not- be sequential, nor need even be in ascenidng order, but I'm writing them this way to simplify matters.) You currently have a hunt group with 25 lines, with the numbers starting at xxx-y101 and going to xxx-y125. You only "give out" the main number, xxx-y101 and when that's busy, calls hunt over to y102, y103 ... y125. What you should do now is get an additional ten numbers (or, perhaps, exchange the xxx-y116-y125 ones) in the sequence: xxx-y091 -> xxx-y100. These ten numbers/lines should be hooked up to 'hunt' as well, and when all are busy, should continue the hunt into the old numbers, xxx-y101. You give out the super secret high speed main number xxx-y091 to your extra value customers, and do NOT give it out to the low speed folk. For good measure, you might also get an additional line xxx-y090 which you give out to NOBODY except yourself for dial-in. So, again, you will now have the following: xxx-y090 <- super secret number known only to you xxx-y091 <- start of hi speed hunt sequence * xxx-y092 ... <- the hunt sequence for hi speed xxx-y100 xxx-y101 <- start of low speed hunt ** xxx-y102 ... xxx-y125 <- end of low speed hunt * is the high speed start, you give out this number to your valued cust- omers. ** is low speed start (-and- is hunted over when high speeds are busy). dannyb@panix.com adds: all the usual disclaimers regarding liability, intelligence, accuracy apply. spelling disclaimer is doubled. ------------------------------ Date: Wed, 15 Dec 93 10:42 EST From: johnl@iecc.com (John R Levine) Subject: Re: Ethernet Over Laser Link Organization: I.E.C.C. Bob Lummis (lummis@alsys1.aecom.yu.edu) wrote: > I am looking for a way to send Ethernet across a public street. Somebody > told me there is a $2500 pair of laser devices that can do that. Another > person in this newsgroup said $5,000 but gave no brand names. I know of the > LCI brand of device that costs more like $15,000 per link (both ends). I'm surprised that nobody's mentioned NCR Wavelan. It's a 2 mb/sec wireless Ethernet that uses 900 MHz spread spectrum transmission. It's good up to about 300 feet with the included omnidirectional antennas, several miles line of sight with outdoor yagis. They're really cheap, list price $800 per node, dealer price about $600. (NCR sells only to distributors who in turn sell only to dealers; I found that the easiest way to get my hands on them was to become a dealer.) For the security minded, there's an optional link-level DES encryption chip, though it's pretty hard to intercept already unless you know which of the 50,000 possible scrambling codes a particular network is using. The main complaint is that they're packaged as ISA or MCA cards to be plugged into your PC, so if you use any other kind of computer, you lose. On the other hand, at that price, you can throw in an old 286 PC and a generic Ethernet card, run PCROUTE or PCBRIDGE, and still have an Ethernet bridge or router for $1000 per end. I use a pair with PC route to connect my home Ethernet to the Internet. At 300 feet, it works adequately (except when it's raining heavily) but if I ever get around to installing the outside antennae, the rain problem should go away. If you call NCR headquarters in Dayton OH, there's a guy there who can send you some information. If you can't find a dealer and don't want to become one, I suppose you could buy them through me. Regards, John Levine, johnl@iecc.com, {spdcc|ima|world}!iecc!johnl ------------------------------ Subject: Re: Computer Cannot Receive From Modem From: a_rubin@dsg4.dse.beckman.com (Arthur Rubin) Date: 15 Dec 93 18:17:40 GMT Organization: Beckman Instruments, Inc. In gast@CS.UCLA.EDU writes: > I just purchased a new computer. I have 2400 baud modem and cable > that works just great with my old computer. With the new one, the > computer can send to the modem fine, but cannot receive anything from > the modem. For example, the computer tells the modem to dial a > number, the modem does, carrier *is* detected (per the modem light), > but the program never detects anything being sent by the modem. (Echo > does not work at all either). You may be able to solve the problem with software. It is possible that the "connect" line is not connected to the card, so your computer is assuming that there is no data, but that software can override. Also, I've discovered that modem cables are not quite standardized. Check the manual for your modem and computer to see if you need a non-standard cable to connect the two. (Posting this on the newsgroup/forum for your specific computer and/or modem may be more helpful.) Arthur L. Rubin: a_rubin@dsg4.dse.beckman.com (work) Beckman Instruments/Brea 216-5888@mcimail.com 70707.453@compuserve.com arthur@pnet01.cts.com (personal) My opinions are my own, and do not represent those of my employer. ------------------------------ From: jay@coyote.rain.org (Jay Hennigan) Subject: Re: Computer Cannot Receive From Modem Date: 16 Dec 1993 20:50:03 -0800 Organization: Regional Access Information Network (RAIN) In article gast@CS.UCLA.EDU (David Gast) writes: > I just purchased a new computer. I have 2400 baud modem and cable > that works just great with my old computer. With the new one, the > computer can send to the modem fine, but cannot receive anything from > the modem. For example, the computer tells the modem to dial a > number, the modem does, carrier *is* detected (per the modem light), > but the program never detects anything being sent by the modem. (Echo > does not work at all either). > Unfortunately, the I/O card does not appear, at least according to the > instruction manual, to have any dip switches. > Any ideas what I need to do? Get a new card? You'll probably wind up getting a new card, but you can find out for sure by making a simple loopback adapter from a DB-25 connector that plugs into the card. Connect together pins 2 and 3. Also connect together pins 4 and 5, and lastly connect together pins 6, 8 and 20. Plug this into the card and you should get echo. If so, the card is probably OK and the trouble is in the modem or cable. A similar connector of the opposite gender can be plugged into the modem. If it is set to auto-answer, then an incoming caller will get echo if the modem is OK. The pin 2-3 jumper loops the transmitted and received data. The 4-5 and 6-8-20 jumpers may or may not be required, and are used in some cases for "handshaking" signals between the computer and modem so that each device can determine if the other is present and ready. From your description of the problem, it sounds as if the card is defective. ------------------------------ Date: Wed, 15 Dec 1993 11:16:00 -0500 From: msb@sq.com (Mark Brader) Subject: Re: NPA 905 Not Universally Recognized David Esan (de@moscom.com) writes: > The 905 NPA went live on 15 October, the pages were not filed until > 22 November. ... sloppy work on the part of BellCore. ... Even worse. The official date for 905 was actually October 4. I just did some experiments with a friend in area code 905 who is a local call away from me here in 416. As expected, he can still reach me by dialing NXX-XXXX or 416-NXX-XXXX. If he tries 905-NXX-XXXX, which is wrong, the recording he gets says "The number you have dialed is a 10-digit local number. Please dial 416 plus NXX-XXXX" -- which is right, but maybe a bit confusing. As noted previously, Call Return here announces the last number that called you before giving you the option to return the call, and it has always given the area code. His calls to me are still given as being from 416, irrespective of which way he dials. Similarly, I can dial his number as NXX-XXXX or 905-NXX-XXXX. If I try 416-NXX-XXXX, I get fast busy (reorder). I tried a number that is in 416; I can dial it as NXX-XXXX or 416-NXX-XXXX. If I try 905-NXX-XXXX, I get a "cannot be completed as dialed" recording. In the days when 905 and other codes reached Mexico, how many digits had to be dialed after the pseudo area code? Our Moderator thinks that a couple of years out of use is sufficiently long to avoid a serious nuisance of wrong-language wrong-number calls; I think he underestimates the number of people who do things like putting an obsolete code on business stationery or writing down a number and calling it years later. But if these calls will fail to complete anyway, no problem. Was the answer different for different pseudo area codes? Mark Brader SoftQuad Inc., Toronto utzoo!sq!msb, msb@sq.com [Moderator's Note: Actually, there were the same number of digits; they were just parsed differently. And the did not refer to it as an 'area code', but rather, an 'access code' (I think). What we actually dialed was '90' plus a 5 then the number in Mexico City if my memory is correct. PAT] ------------------------------ Downloaded From P-80 International Information Systems 304-744-2253