Received: from buita.bu.edu by buit1.bu.edu (3.2/4.7) id AA16339; Sat, 30 May 87 17:31:26 EDT Return-Path: Received: by buita.bu.edu (1.1/4.7) id AA05659; Sat, 30 May 87 17:31:30 EDT Message-Id: <8705302131.AA05659@buita.bu.edu> Date: Sat, 30 May 87 17:28:08 EDT From: The Moderator (JSol) Reply-To: TELECOM@BUIT1.BU.EDU Subject: TELECOM Digest V7 #8 To: TELECOM@BUIT1.BU.EDU Status: O TELECOM Digest Sat, 30 May 87 17:28:08 EDT Volume 7 : Issue 8 Today's Topics: New area code 890! Cellular Fraud Cellular phone ids Re: Ringback codes Re: cellular inquiry ---------------------------------------------------------------------- Date: Fri, 29 May 87 08:04:49 EDT From: prindle@nadc.arpa (F. Prindle) To: telecom@buit1.bu.edu Subject: New area code 890! An insert in my latest phone bill says AT&T is going to start using the 890 area code to augment it's current 800 toll free service; I suppose, with the need to allocate some of the 800 prefixes to the alternates, they have simply run out of prefixes in 800. But 890 surely is a strange area code, with that 9 in the middle; my ESS currently doesn't parse 1-890-xxx-xxxx correctly, thinking that it is a local prefix of 890 and not an area code. Is this the first area code that is not N0X or N1X? Frank Prindle Prindle@NADC.arpa ------------------------------ Date: Sun 24 May 87 03:21:33-EDT From: Doug Reuben Subject: Cellular Fraud To: Telecom@XX.LCS.MIT.EDU Cc: s.m-cirillo%KLA.WESLYN@Wesleyan.Bitnet, cc004019@brownvm.bitnet Well, although Cellular is "untraceable" in the same way that regular phones are, it still is not the ideal system to commit toll fraud on. >From what I understand about how the cellular system works, a new subscriber is assigned a phone number, and then given a 4 digit code that is unique to his cellular phone. Thus, the chip that is placed into a cell phone to identify it may have a # like this: 212-909-1234-5555. The 5555 is the 4 digit ID code, very much like the PIN number on Bell System Calling Cards. When you request service, you have to have your number "turned on" at the Cellular Company. And, like a calling card, the Cell Co. checks to see if the special ID # matches before it puts the call through (It checks a lot of other things too, like signal strength and stuff, but that's not important now...). So in order for someone to make free calls, he has to know an active number, and then go to the dealer who sold the phone with that number and ask the dealer what the ID number is. If the dealer is unscrupulous, he will give out the ID number, and THEN you can make free calls. However, in no more than a month, if the customer finds that there are a lot of calls which he did not make, he can call the Cell. Co. and demand that they remove the calls from his bill. The Cell. Co. will also change the ID number, and if they are smart will check out the Cellular phone dealer to see if he gave away the ID code to that specific number. So what free Cellular service will get you is at best a month's worth of calls, and that's about it. Also, you will have to go to different dealers all the time, since if it happened with the same dealer a lot the Cell Co. might investigate the Cellular phone dealer. Also, you would have to change your number every month if you wanted people to call you. Stolen Bell Cards work the same way, although faster. If you steal a Bell System Calling Card, and you use it a lot, the local Bell Company (or, heaven forbid, the GTE company if you can manage to use a calling card there! :-) ) will call the paying customer and ask "did you make 300 calls today?". Usually, the customer says no, so they just cancel the card and issue a new PIN number to the customer, usually right away. (The system to assign PIN numbers is almost instantaneous, it seems. The minute they assign you a PIN # you can use it!). Assuming the free calls were made from a payphone, the Bell Co. will still call the destination numbers to see if anyone knows who called them, in hopes of catching the person. If they get enough people to say "Sure, I know Mr. so-and-so", then they may go after the person who stole the card. The point is that Bell Calling Cards have a built in safety system to protect against fraud. (The alternates don't have anything quite as sophisticated...). It would not be very hard to put a similar "excessive use" system of cellular phones. Thus, if cell fraud becomes pervasive, it should be a relatively simple manner to end it, and thus Cell Fraud is really not much better than the standard stuff people do at payphones. Also, Bell System Calling Cards can be used as frequently as you like. The normal "warning" occurs if you have more that 30 calls in 3 hours (or is it 36?). However, if you use your Bell Card a lot (like I do), then you can ask your local Bell Co. to put a little note on your account that you are a heavy user of the card. That way, if you make more than 30 calls in 3 hours (or whatever), you don't get the card turned off. This is VERY convenient if you are away from home and don't want to worry about how many calls you make. Basically then, the people who designed the Cellular System were smart, and they made sure you can't cheat it too easily or too long. Seeing how easy it is for them to stop Calling Card fraud, I see no reason why with the Cellular system set up the way it is that they can't prevent Cell fraud as well... (I'm sure I made a few mistakes there, so any corrections are welcome...) Well, that's my two cents worth! - -Doug REUBEN@WESLYN.BITNET S.D-REUBEN%KLA.WESLYN%WESLEYAN.BITNET@WISCVM.ARPA ...seismo!weslyn.bitnet!reuben (UUCP) ------- ------------------------------ Date: Wed, 27 May 87 15:30:43 edt From: gordon!davido (David Ornstein) Subject: Cellular phone ids To: telecom@xx.lcs.mit.edu Somebody broke into my car a while ago and they took my Alpine stereo system, but left my cellular phone. This got me thinking about their reasoning. The obvious reason for not taking it is that the real guts of the thing are burried in a box with 3 Z80s in it under the back of the car. My second thought was that they knew that it would be almost useless to them unless they could change the number of the phone. Is this true? COuld somebody fill me in on the background of the custom part of the average cellular phone? Is it just a 10-byte prom with my phone number in it? -- ----------------------------------------------------------------------------- David Ornstein "Never join a religion that has a water slide." Internet: davido@gordon UUCP: {mit-eddie|seismo}!mirror!gordon!davido or {harvard|ames|decvax|husc6}!necntc!davido US Snail: Access Technology, 6 Pleasant St, Natck MA 01760 ----------------------------------------------------------------------------- ------------------------------ To: comp-dcom-telecom@seismo.CSS.GOV From: elroy!grieggs%jplpro.JPL.NASA.GOV@seismo.CSS.GOV (John T. Grieggs) Subject: Re: Ringback codes Date: 29 May 87 00:03:29 GMT In article <8705171242.AA10372@ci.sei.cmu.edu> pdb@SEI.CMU.EDU (Pat Barron) writes: >... >Your CO is smart enough to know that it makes no sense to allow you to >call yourself. Using the credit card (apparently) bypasses your CO. At least on GTE in Torrance, the CO is not all that smart. I am able to dial my own number, hang up immediately, and have it ring once... _john -- John T. Grieggs (Telos @Jet Propulsion Laboratory) 4800 Oak Grove Drive, Pasadena, Ca. 91109 M/S 301-260A (818) 354-0465 Uucp: {cit-vax,elroy,chas2}!jplpro!grieggs Arpa: ...jplpro!grieggs@cit-vax.ARPA ------------------------------ To: comp-dcom-telecom@RUTGERS.EDU From: keithh@rosevax.rosemount.com (Keith Holmquist) Subject: Re: cellular inquiry Date: 28 May 87 14:20:58 GMT > Subject: cellular inquiry > > To: telecom@buit1.bu.edu > > I do not yet understand enough about the cellular technology, and perhaps the > answers are relatively simple and of interest to others as well as me. > (If not, the moderator may wish to divert the discussion). > > Clearly a customer can rent a cellular phone, and register for service in a > particular area; then they can both send and receive calls. > > The technology somehow recognizes and notes the user's location as they drive > about, and knows in what cell to ring them if an outsider calls them. First my background in cellular was as a design engineer for both mobile units and base station, primarily designed the brain sections along with signal and audio processing. It`s been 2 years since I`ve worked on it so some of my answers may be out dated but I`ll try not to lead you astray. > > The questions: > > 1. How is the location-recognition accomplished? Does one's currently inactive > cellular phone burp regularly and its address get re-noted? Does that drain > your battery? If it's really off are callers told something different from > "ring...ring...ring...no answer"? The systems do not know where a particular subscriber is at any time. As a mobile unit cruises the streets It locks on to a dedicated channel called the control channel. As travel progresses the mobile periodical scans all the avaible control channels and continually looks for the stronges signal. When a call is initiated all the control channels in a given system ( i.e. not all the systems in the country) transmit the request. The mobil whose being called then responds on it present control channel a voice channel is then assigned for the remainder of the call. I'm not clear on what you mean by "burp". How a non responding mobile unit would be delt with is really up to the individual systems. I am unaware of any regulations in that area, the systems I worked on responded with a recorded messge similar to "The mobil unit you are requesting is unavailable at this time" or something equelly as dry and tasteless. > > 2. Over how large an area does this typically work? It works over an entire system in any one geographical area. > > 3. If an owner drives from SF, normal location, to New York, and tries to cal > out, what happens? Typically the way this is being handled is the call is intercepted and the caller is given the option to place the call by credit card. It is entirely possible for the system to decide if this caller is registered with It in another city but would reqiure a nation wide network from cellular system to cellular system. I have not read any articles saying this is reality yet. It was all just a dream 3 years ago. > > 4. If while they are in New York, someone in SF, their home, calls them, what > happens? I believe presently that the caller from SF get the message you are unavailable. There are provisions in the protocol for a mobil to register whenever it roams from its preferred system and from that point it is up to the base systems to determine if the subscriber is valid or not. Again a nation wide network is needed. see above response > /------------\ > 5. Can you register as a visitor in a distant area, electronically or by > calling in or however? Does this enable anyone else to call you from long > distance? Must they know, essentially, where you went and when you're there? Now an editorial comment: The cellular concept is a good one but due to pressures to not allow it to become a monoply it may never reach it's full potential. If one uses the as an example the Bell system, I think you would agree that the nation wide/ world wide coverage was made easier by allowing one large operating system the privealage to design and implement the entire system. Could you imagine the confusion of having Dick and Jane Telephone on the west coas and Ted and Alice on the East. Cellular is presently in that state although a few large operators seem to be positioning themselves for more complete coverage. Just thought I comment. The end An opinionated source Keith > > [ cellular response] ------------------------------ End of TELECOM Digest *********************