TELECOM Digest Thu, 30 Jun 94 14:35:00 CDT Volume 14 : Issue 306 Inside This Issue: Editor: Patrick A. Townson Re: Cellular Phones and Lightning (Steven King) Re: Cellular Phone and Tower Handshaking (Steven King) Re: Motorola Digital Cellular Phone (Donald J. Zanolla) Re: Motorola Digital Cellular Phone (Bernard Rupe) Re: Motorola Digital Cellular Phone (jskene@Delphi.com) Re: Satellite Telephone Wanted (Greg Monti) Re: Another National N11 Code Request (ssatchell@bix.com) Re: Help on Dial Line Protection From Storms (ssatchell@bix.com) Re: Who's That Voice? (Les Reeves) Her Voice Comes in Warm and Clear (Associated Press via Steve Bauer) Water Sensors For Equipment Rooms (Donald W. Filkins) Personal PBX Construction Article (Les Reeves) 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. 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Any organizations listed are for identification purposes only and messages should not be considered any official expression by the organization. ---------------------------------------------------------------------- From: king@wildebeest.cig.mot.com (Steven King, Software Archaeologist) Subject: Re: Cellular Phones and Lightning Date: 29 Jun 1994 14:24:17 GMT Organization: Motorola Cellular Infrastructure Group Reply-To: king@cig.mot.com shawnlg@netcom.com (Shawn Gordhamer) publicly declared: > Someone told me that in a lightning storm, lightning can follow the > radio waves given out by your cellular phone. I assume this is > because the air is more ionized where the waves are strong. Is this > true? Is it unsafe to use a handheld cellular phone in a lightning > storm? I'm not talking about a mobile phone with a tall antenna. Oh yes, it's absolutely true. In fact, this is where the real risk of brain cancer lies. The cellphones don't directly cause it, but getting hit by lighting is a *definite* cause of cancer. Even if you don't feel it, you've probably been hit by a "microspark" if you've ever used the phone during a lighting storm. Cordless phones aren't an issue. As we all know (based on legal rulings in the U.S.) cordless phones are broadcast emissions while cellular phones are point-to-point between the phone and base station. You can't get zapped while talking on a cordless phone for this reason. By the way, don't *ever* use a cellular phone in New Jersey. The Red Lectroids from the Eighth Dimension can slip along the radio waves and take over your brain. Ever see the movie "Buckaroo Banzai"? 'Nuff said! Okay, enough fun. No, lighting won't "follow the radio waves" back to your phone. At least, I've never heard of that effect. I really doubt that 600 mW of omnidirectional RF can ionize anything, let alone make a more conductive path between the clouds and ground. It does make a nice urban legend, though. Steven King -- Motorola Cellular Infrastructure Group ------------------------------ From: king@wildebeest.cig.mot.com (Steven King, Software Archaeologist) Subject: Re: Cellular Phone and Tower Handshaking Date: 29 Jun 1994 18:18:29 GMT Organization: Motorola Cellular Infrastructure Group Reply-To: king@cig.mot.com shawnlg@netcom.com (Shawn Gordhamer) publicly declared: > Sometimes when I turn my phone on, it doesn't bother talking to the > tower at all. Sometimes, it transmits for a short period of time. > But it usually does this once and not at set intervals. With this in > mind, I have come up with the following theory about how a phone and > tower keep track of each other. Someone please let me know if there > is any truth in this. Here's what goes on. This may be slightly inaccurate; I haven't needed to look at the air interface spec for a number of years. Some of the relevant brain cells have undoubtedly been recycled by now. When you turn on your phone, it checks its memory to see if you're on the "A" carrier or the "B" carrier. It then starts scanning the signalling channels for the appropriate carrier to see which has the strongest signal. (If it can't find a channel on the home carrier it'll scan the other carrier's signalling channels, and then turn on the "No Service" lamp if it still can't find anything.) The phone will continually rescan the signalling channels to stay tuned to the strongest one. Depending on how your cellular system is set up, your mobile may have to periodically register with the system. Keeping track of your mobile saves effort when you have an incoming call -- the system can direct the page instead of blasting it across all cells. Periodically the base sites will send out a "registration check" command. This command contains a time stamp. Your mobile remembers the last time it registered and will re-register if it's past the registration period. Typically systems will want the mobile to register once an hour or so, but that's configurable by the cellular operating company. If the mobile has been turned off for more than an hour, it will always notice that it's past its registration time and will re-register. If it has been turned off for less than an hour it will wait until the full hour has elapsed before re-registering. This explains why your mobile "sometimes" sends data to the cell on power-up. The phone does *not* re-register each time it moves into a new cell, just when the timer expires. The timers are set up on a per-system basis. If you're moving along a corridor serviced by several companies (say, a freeway between two cities) it will probably re-register when it moves into a different system. > When actually talking on my phone, the towers themselves must monitor > my signal strength. I can hear my phone change frequencies quite > often while I talk, even when I am just pasing around one room. The > phone never transmits tower changes that often when it is not being > used. While you're talking, the cell signals your phone by blanking the voice path and sending a burst of digital data on the same channel. You hear this as a momentary blank spot in conversation. However, the only things the cell should be telling your phone at this time are "go to another channel" or "change your power level". You shouldn't be handing off just walking around a room. There's some hysterisis in the signal strength determination to keep mobiles in the fringe between two cells from handing off back and forth rapidly. Ditto for changing power levels. I don't know why you're hearing frequent drop-outs while you're talking, but I suspect your phone (or the cell) shouldn't be doing that. Can you borrow someone else's phone and test it under the same conditions? Steven King -- Motorola Cellular Infrastructure Group ------------------------------ From: zanolla@agouti.cig.mot.com (Donald J. Zanolla) Subject: Re: Motorola Digital Cellular Phone Date: 29 Jun 94 18:00:58 GMT Organization: Motorola Cellulsr Infrastructure Group idp3286@hertz.njit.edu (Ian Daniel Plotkin) writes: > Does anyone have any experience with Motorola's new Digital flip-fone? > Is digital cellular as widespread as analog yet? The local carrier > here in central NJ is Comcast/CellularOne. Does anyone know if NJ is > covered by a digital network? While the other (analog) flipfones go > for around $50 /w signon deal, is it worth it at this point in time to > shell out the $300 or so (/w signon deal) for the digital phone? Any > info would be appreciated! NO, digital is not vary widespread, as yet; my guess would be about 5% of the cellular services are digital. If you are considering a digital phone then: 1 - Make sure it is a dual-mode phone; dual-mode phones will operate as either digital or analog. When the phone powers-up in the default mode (either digital or analog) it will look for service in that mode; if there is no service available then it will search for service in the other mode. This is important when you are out of your home service area; the phone will be able to find you service in either mode. 2 - The default mode is controlable by the phone user NOT the service provider. This would be useful if you are not happy with the current mode and YOU can change to the other mode to see if the service is better there. The cellular provides are pushing digital because it gives better call security AND they can get more calls on the same piece of copper as with analog. Unless, the cellular provide is giving you much lower cost/minute as compared to analog then probably you should stay with a analog phone. Donald Zanolla zanolla@agouti.cig.mot.com ------------------------------ From: rupe@wombat.cig.mot.com (Bernard Rupe) Subject: Re: Motorola Digital Cellular Phone Date: 29 Jun 1994 15:31:29 GMT Organization: Cellular Infrastructure Group, Motorola In article idp3286@hertz.njit.edu (Ian Daniel Plotkin) writes: > Does anyone have any experience with Motorola's new Digital flip-fone? > Is digital cellular as widespread as analog yet? The local carrier > here in central NJ is Comcast/CellularOne. Does anyone know if NJ is > covered by a digital network? While the other (analog) flipfones go > for around $50 /w signon deal, is it worth it at this point in time to > shell out the $300 or so (/w signon deal) for the digital phone? Any > info would be appreciated! TDMA (digital cellular) is not as near wide spread as analog yet. In fact, Ameritech has decided that TDMA does not meet its needs and so will not deploy it. They are instead waiting for CDMA (a competing form of digital). The main user difference (ie. outside of the obvious operator benefits) between digital and analog is that digital will maintain a higher signal quality but will suddenly drop where analog would continue the call with degraded signal quality. With a strong signal, I don't think most people would notice much of a difference between the two. Motorola Cellular Infrastructure (I'm not offically speaking for the company, but am just relaying information as I understand it) has taken the position that CDMA is a superior technology to TDMA. We will be deploying CMDA systems (ie. non-trial, full commercial) at the beginning of next year. US West and AirTouch (formerly PacTel Cellular) will be deploying CDMA. I'm sure there are people around who would argue that TDMA meets all of our needs. We may very well end up with both technologies being widely deployed. One of them could also win out. In that case, either TDMA or CDMA phones might be worthless four or five years from now. Bernie Rupe 1501 W. Shure Drive Room 1315 Motorola, Inc. Arlington Heights, IL 60004 Cellular Infrastructure Group +1 708 632 2814 rupe@cig.mot.com ------------------------------ From: jskene@news.delphi.com Subject: Re: Motorola Digital Cellular Phone Date: 29 Jun 1994 21:28:11 -0000 Organization: Delphi Internet Services Corporation Digital cellular has several advantages over the older analog systems. You will suffer much less congestion, typically have clearer voice, and will not be susceptible to illegal phone taps from someone with a Radio SHack scanner. The extra cost may well be worth it if these are important issues to you. ------------------------------ From: Greg Monti Date: Wed, 29 Jun 1994 15:57:26 EDT Subject: Re: Satellite Telephone Wanted Here are manufacturers I know of that sell phones that can be used to communicate on the worldwide Inmarsat system. In this business, "portable" is a relative term. Ask what they have; they are getting lighter and cheaper with time. A demo I saw last week was of a 40 or 50-pound aluminum suitcase with a phone and all transmit and receive electronics in it. To use it, you must asssemble and deploy a "parasol" antenna made of metal fabric and attach it to the RF electronics. The antenna is about 2 feet in diamter when deployed. You must then find one of the four Inmarsat satellites using approximate pointing instructions that are included. At the frequency used, about 1.5 GHz, the beam width of a 0.6 meter antenna is fairly wide so "finding" the spacecraft is not as hard as it sounds. The antenna must still be peaked for best signal. Once "commissioned" (given an account) with Inmarsat or a reseller, the phone is assigned a seven-digit number and can make incoming and outgoing calls. Outgoing calls are dialed 00 + country code + city code + local number. Incoming calls to the phone are dialed as if each Inmarsat satellite is its own "country". The country codes for Inmarsat for the Atlantic Ocean region are 871 and 874 (I forget which is east and which is west). The country codes for Pacific and Indian Ocean regions are 872 and 873, maybe not in that order. Sort of like old-fashioned "roaming" with cellular; you must know which market (in this case, spacecraft) the phone is "in" to reach it. The phones are in the $10,000 to $50,000 range each if bought new. I have no idea if any of these companies have leasing programs. The "air time" is between $8.00 and $10.00 per minute. But, hey, it will work atop the Himalayas or on Gilligan's Island. Inmaresat birds are geostanionary satellites and cannot be communicated with north of about 83 N nor south of about 83 S latitude. Battery not included. You either plug it in to 120 or 240 volts or you bring a battery pack or maybe a motorcycle battery -- and some way of charging it. I understand that climbers who did one of the big mountains in Asia hauled one of these things up there and called to report their success, as well as -- presumably -- to retrieve their messages from voice mail back home. Mobile TeleSystems, Inc., 300 Professional Drive, Gaithersburg, MD 20879; 301 590-8500; fax 301 590-8558. Olivia Communications Group, 1 Park Place, 621 NW 53rd Street, Boca Raton, FL 33487-8211; 407 995-1422; fax 407 995-1499. Mackay Communications, 300 Columbus Circle, Edison, NJ 08837; 908 225-0909; fax 908 225-2848. Calian Communications Systems, Ltd., 300 Leggett Drive, Kanata, Ontario K2K 1Y5 Canada; 613 592-3020; fax 613 592-3378. Comsat Mobile Communications, 22300 Comsat Drive, Clarksburg, MD 20871; 301 428-2222; fax 301 601-5951. GTE Government Systems, don't have address. Suggest starting with 1700 Old Meadow Road, McLean, VA 22102; 703 848-1000; fax 703 848-0004. Greg Monti, Tech Mgr, FISPO, Distribution Division National Public Radio Phone: 202 414-3343 635 Massachusetts Av NW Fax: 202 414-3036 Washington, DC 20001-3753 Internet: gmonti@npr.org ------------------------------ From: ssatchell@BIX.com (ssatchell on BIX) Subject: Re: Another National N11 Code Request Date: 30 Jun 94 06:19:17 GMT Organization: Delphi Internet Services Corporation Greg Monti writes: > With 011 and 111 unavailable, and with 411 and 911 in use in most > places, that leaves only six N11 codes unused (211, 311, 511, 611, > 711, 811). 611, 811 (and if applications from newspepers are > approved, 311 and 511) are already used in some places. The article > notes that the FCC has opened a pleading cycle on the subject. > Comments to the Commission are due Aug. 19. "Reply comments" are due > Sept. 23. There are some other common usages. 611 has been used extensively for "repair servie", while "811" is used to reach the telephone office. You find these in RBOCs as a rule. ------------------------------ From: ssatchell@BIX.com (ssatchell on BIX) Subject: Re: Help on Dial Line Protection From Storms Date: 30 Jun 94 06:24:38 GMT Organization: Delphi Internet Services Corporation mike_foltz@sgate.com writes: > I am experiancing problems on our BBS and Internet dial-in lines when > there is wicked lighting storms. We have a total of 30 lines both > local and 1800 numbers all feeding Multitech a rack mount card cage > with MT1432BR modems. On the RS-232 the modems feed a Shiva lan rover > for ARA or a cisco CS-516 for Internet access. We also have other > vendors modems such as Intel, ZyXel and Scout modems for testing, SLIP > and fax services. > I seems that the storms do most harm on the Multitech modems, but it > appears not to bother the other modems. The past 2 storms i have had > to reprogram the Multitechs most lost what they were originally setup > with. Some did not recover even with reprogramming. I am able to > connect but either get no data or just garbage. > Is there some type of pads, isolators etc that can be used on the > dialup lines to protect the modems from getting trashed and also let > 14.4K rates pass? Is there guides to BBS or Modem installations that > address this issue? I am a bit confused why the other modems didn't > have problems? They have phone lines that come in over the same > copper bundle that feeds the Multitechs. Here are some tips: you can get surge suppressors which mount on 66 blocks. Punch down the lines from the telco onto the 66 block. The surge suppressors then bridge the pair; connect the earth side to a really good ground. (Indee, locate the 66 block near a very good ground point to keep the ground wire short.) Here's the trick: make sure you have AT LEAST 50 feet of inside wire between your 66 block and the modems. 100 feet is better. If you decide to use 100 feet but the distance between the 66 block and modems is less, mount the wire on the wall in a serpentine manner, keeping each run at least 6 inches apart. The 66-block surge suppressors keeps the spikes down to a reasonable level. The extra wire added enough distributed series inductance and parallel capacitance that any spikes that *do* get through are attenuated nicely. The stuff to make this happen is available from Anixter and others. ------------------------------ From: lreeves@crl.com (Les Reeves) Subject: Re: Who's That Voice? Date: 30 Jun 1994 12:21:57 -0700 Organization: CRL Dialup Internet Access (415) 705-6060 [login: guest] Jeffrey W. McKeough (jwm@student.umass.edu) wrote: > After reading an interesting discussion in the archives about Jane > Barbe, the former voice of the Bell System, the voice of the time in > several cities, and of many Octel systems (at least those that have > not upgraded to a Marsha Graham software release), I was wondering if > anyone has any information about yet another of those famous voices. > The woman in question has done many recordings including the > ubiquitous AT&T carrier identification chime and calling card auto > attendant, the EasyReach voice prompts, RBOC recordings (including > NYNEX's return call/repeat call prompts, and the new "You must dial 1+ > the area code intercepts). I've always found it interesting to be > able to put a name with a voice, so I thought I'd ask. Her name is Pat Fleet. Les lreeves@crl.com Atlanta,GA 404.874.7806 ------------------------------ From: steve.bauer@boardwatch.com Organization: Boardwatch Magazine Date: Wed, 29 Jun 94 06:19:39 MST Subject: Her Voice Comes in Warm and Clear (was Re: Who's That Voice?) In TELECOM Digest 14, 302 the question was posed regarding who the female voice is on many telephone systems. Jeff, You asked about who the female voice on phone systems was, well, I think I have the answer. The following should answer any questions you may have. HER VOICE COMES IN WARM AND CLEAR Note: This article is reprinted with permission from the Associated Press. OAKLAND, Calif.--Joan Kenley sometimes talks to herself, but that's understandable. After all, millions of people listen to her. Among other things, Kenley is the ubiquitous voice of Voice Mail, Pacific Bell's computerized answering service that more businesses are turning to instead of human operators. When you pick up the phone at a hotel, Kenley could be on the other end. She's the voice of Guest Messenger, a Sheraton Hotel chain service similar to Voice Mail. Or you might hear her pear-shaped tones rattling off the prices at computerized grocery store checkout counters. "I'm even the English-speaking voice on pay phones in Japan," said Kenley, who is also the voice on software designer Northern Telecom's Meridian Mail and the interstate long distance voice for several companies, including Michigan and Ohio Bell. One reason her voice is so popular is that the melody "tends not to go away" and so allows sound technicians to mix old tapes with new ones. If there is a criticism of her voice, it's that "it's too real." "People can easily start talking to it, but that's a compliment as well." She even does it herself. Kenley said she was checking into a hotel recently "and when I picked up the house phone I ended up talking to myself. It's kind of spooky." Kenley has done price-voicing for 50 grocery store chains. The automated service sounds out the cost of an item when it is passed over the checkout machine. "My uncle in Cleveland was leaving a checkout where I say "thank you" and he answered, "You're welcome, Joan," she said. Kenley, who has a Ph.D. in psychology, said her big break came ten years ago when she was contacted by University of California professor Forrest Mozer, who developed a way to put the human voice on a computer chip. Mozer felt the best way for humans to "interface" with computers would be vocally. "He said he wanted a voice that was warm, but not too sexy," Kenley recalled. Kenley says her work is "a kind of immortality." "A hundred years from now, I'll be long gone. But my voice will still be going out into the stratosphere saying, "Two dollars and fifty cents, please." ------------------------------ From: dfilkins@iastate.edu (Donald W Filkins) Subject: Water Sensors For Equipment Rooms Date: 30 Jun 1994 18:40:28 GMT Organization: Iowa State University, Ames, Iowa (USA) I work for the Iowa State University Telecommunications Dept. We have several equipment rooms we would like to monitor for water intrusion. I have only one product in mind so far (Dorlen Products Water Alert) and would like to be able to evaluate a few more. So far none of our equipment vendors has come up with an alternate source so any additonal info would be helpful. We already have autodialers in place to monitor door alarms and other environmental parameters so all I require is a sensor with a contact closure ( or open ) and the approprate power supply if the unit is not battery powered. I would prefer some sort of ac or switch battery powered device to avoid the hassle of periodically changing batteries. Please post to this group or email me directly. Thanks in advance, Don Filkins ------------------------------ From: lreeves@crl.com (Les Reeves) Subject: Personal PBX Construction Article Date: 30 Jun 1994 12:11:17 -0700 Organization: CRL Dialup Internet Access (415) 705-6060 [login: guest] The July issue of {The Computer Applications Journal} has a construction article for a build-it-yourself personal PBX. The article describes an eight-station PBX which uses standard 2500 type sets. The little PBX is designed around industry-standard IC's, and uses solid telephony design techniques. The controller is an 8031, and the switching matrix is a M093 IC. All the circuit elements of the PBX, such as the Ring Generator, Subscriber Line Interface Circuit (SLIC), DTMF receiver and tone generator, are described in detail. Even if you are not at all interested in building a PBX, this article is an excellent tutorial on how they are designed. Les lreeves@crl.com Atlanta,GA 404.874.7806 ------------------------------ End of TELECOM Digest V14 #306 ******************************