______________________________________ ________| l a s l o c o m m . n e t |_______ \ | | / \ I | t e c h n i c a l j o u r n a l | iv / / |______________________________________| \ /__________) (_________\ laslocomm.net presents... the laslocomm.net technical journal ---=== free dmitry! http://www.freesklyarov.org/ ===--- support operation enduring freedom volume 1, issue 4 | september/october 2001 in this issue editorial comments interesting news items article: numbering, signaling, etc in the phone system [access denied] article: prepaid calling cards [laslo] article: setting up a dialup bbs using waffle and UUCP [laslo] call for authors copyrights, etc redistribution =[ editorial comments ]= I won't rant specifically about 9/11/01, other than to say that I'm deeply affected by everything that has happened... hang in there, life is going to be an interesting ride for a while. the urban exploration column has been moved out of the technical journal, and into a sort of zine of its own. you can find it at http://www.laslocomm.net/exploration/places/index.html. =[ interesting news items ]= http://biz.yahoo.com/prnews/010922/hssa015_1.html http://www.atnewyork.com/news/print/0,,8471_882701,00.html http://dailynews.yahoo.com/h/ap/20010914/tc/cell_phones_security_2.html http://www.wired.com/news/print/0,1294,46655,00.html http://dailynews.yahoo.com/h/nm/20010906/tc/microsoft_justice_dc_5.html http://www.fortune.com/indext.jhtml?channel=print_article.jhtml&doc_id=204241 http://dailynews.yahoo.com/htx/nf/20010927/tc/13823_1.html https://lists.wi2600.org/pipermail/2600/2001-October/008183.html http://www.gnu.org/press/2001-10-12-bayonne.txt http://jama.ama-assn.org/issues/v281n18/ffull/jst80027.html http://www.grove-ent.com/americastrikesback.html http://www.phoneplusmag.com/hotnews/1ah2152858.html http://dailynews.yahoo.com/htx/zd/20011004/tc/zero-knowledge_pulls_the_mask_off_1.html http://news.cnet.com/news/0-1004-202-7206084.html =[ article: numbering, signaling, etc in the phone system ]= by access denied [first appeared on the wi2600 mailing list, here: https://lists.wi2600.org/pipermail/2600/2001-September/007893.html, used with permission.] A couple people mentioned they were interested in having me write a bit more about this topic. So I will. I'm mostly going to focus on numbering in North America and DTMF signaling from station to switch. I don't intend to talk about things like Wink Start and Loop Start, E&M Signaling, Single Frequency Signaling etc. For a very complete guide to this stuff see if you can get your hands on a copy of Bellcore Notes on the Networks, SR-2275. So first I'll talk about numbering. On the global scale you have the country code. These are assigned by the ITU and are from 1 to 3 digits in length. The world is broken up into 9 international world zones (IWZs). IWZ1 is North America. IWZ2 in Africa, 3 and 4 are Europe, 5 is Central and South America. 6 is the South Pacific, 7 is Russia. 8 is assigned to East Asia and Special Services such as Freephone (UIFN) and Satellite Telephony. 9 is West and South Asia and the Middle East. Within each Country Code area Area Codes or City Codes. In IWZ1, also called the North American Numbering Plan, we use Area Codes also known as Numbering Plan Areas or NPAs. NPAs are three digits in length. The first digit is between 2 and 9, and the second and third digits are 0 through 9. There are some rules as to how NPAs can be assigned. Any NPA in the format ABB, where B is the same digit is called an Easily Recognizable Code, ERC. This covers for instance the N11 series of codes which are used for things like Emergency numbers (911), Repair services (611) and Directory Assistance (411). Also included in this N00 numbers. These are such services as Premium Services (900), Toll Free (800, etc), Carrier Specific (700), Personal Communicatios Services (Follow Me - 500), etc. Toll free is a special case in that all numbers in the format 8YY are reserved. The Y indicates 0, and 2 through 9. Also currently the plan is that when the 8YY range is exhausted, the toll free space will move into the 88X space. Within each NPA is a Central Office Code (COC) which is also three digits and follows the same format as the NPAs. This is BTW often refered to as NXX. N = 2-9, X=0-9. COCs are often refered to as exchanges or prefixes. COC is at times a misnomer because certain prefixes can go to different central offices depending on where they are dialed from. For instance, 555 (special services), 958 (test numbers), and 976 (premium services). Also in some cases, for instance Toll Free, the COC has nothing to do with the carrier or the location of the number. To add to the confusion are two new features called Local Number Portability and Thousands Block Pooling. In LNP, your number can move with you if you change locations or even carriers within the same Rate Center. With number pooling, instead of assigning an entire block of 10,000 numbers to a local exchage carrier that might not all be used, 1000 can be assigned at a time. Within each COC is a 4 digit line number. When you put these all together you get the phone number or station address that you are used to seeing. In the international format: +1 NPA NXX XXXX. For instance, +1 414 555 1212. The + is used as a shorthand for the international access code in whatever country you are dialing from. See below. Now, signaling. When you take your phone off the hook, your switch notices this and plays a dial tone back to you. This is the switch telling you that it is ready for addressing information. In the modern telephone system, this is acheived by using Dual Tone Multiple Frequency or DTMF. Each number is assigned a unique combination of two tones that the switch can decode to determine the digit sent. The switch can deal with a variety of signals. There are seven special signals, 0+, 0-, 1+, 00+, 00-, 011+, and 101XXXX+, that indicate to the switch that something special needs to happen. But first I want to talk about 7-digit vs. 10-digit dialing. In 7D dialing, to place a local call, you need only dial the NXX-XXXX part of the address. In 10D dialing you need to dial NPA-NXX-XXXX. This varies from location to location. In some cases, neither 7D nor 10D is allowed and you must always dial 1+10D. So, on to the special signals. First is 0+. This means you dial 0-NPA-NXX-XXXX or 0-NXX-XXXX and expect to get an operator to complete it for you. You can tell them the type of billing you would like. This is called operator assisted dialing. Next is 0-. This means you dial 0 alone and get to the operator. Similar to 0+ though depending on where you're calling to with 0+ you might get an interexchange carrier operator or a local exchange carrier operator. Next is 1+ dialing. This is the most common way of dialing. You dial 1-NPA-NXX-XXXX and your calls gets completed by the carrier you are presubscribed to, for instance AT&T. It is necessary to force people to use +1 when dialing long distance for a variety of reasons. One is that when a switch sees the first digit dialed in 1, it knows to start routing to toll trunks. If it sees a 2 through 9, it knows it is a local type call. 00+ and 00- aren't always supported. Generally, 00- will take you to your IXC operator, as will 00+. A lot of it depends on what type of service you have with your IXC. 011+ is for international dialing. 011 is the international access code in the NANP that is represented as + in an international style number. This will route the call through your pre-subscribed carrier as well. If you don't want 1+ and 011+ dialing to route through your presubscribed carrier, you can use 101XXXX+ dialing. This will send it through the carrier you indicate with XXXX. For instance, 1010288 is AT&T. The switch is programmed to look for all of these types of codes. In addition, it is programed to react specially to certain ERC's generally in the format N11. It will immediately complete the call after the third digit is dialed. In some cases, you can dial 1+ before an ERC as in the case of 411. Well, that hopefully was of interest to people. I dunno if I really covered everything that I thought I would at the start, but I didn't really lay it out before hand. If I left anything out or there's some glaring error, please let me know and I'll explain it better. Or if you have a general question feel free to ask as well. ad =[ article: prepaid calling cards ]= by laslo prepaid calling cards are said to be an convenient, economical way to place local and long distance phone calls from any available phone. you can purchase a prepaid card from gas stations, drugstores, unattended vending machines, and many other places (including online). when needed, they can be used from most any phone, including payphones and cellular phones. prepaid cards are also a large, tangled business that does not end when you purchase and use a card. physically using a prepaid card is almost the same as using a long distance extender. you call the toll free number on the card, enter the pin number, and you are connected to some company's computer system which will inform you how many minutes/how much value you have left on the card. the system prompts you for the number you wish to dial, and after a few seconds, the call goes through. technically, there are many more steps, some of which took place before you ever purchased the prepaid card. I'll start with the step just before you purchasing the card. for this example I'll assume you bought a $25.00 prepaid card from a vending machine at a local gas station. the operators of that gas station may own and stock the machine with cards that they buy, or someone else may own and stock the machine (paying a commission, or rent, to the station operators). either way, they pay less than the face value of the card, which makes them a nice profit. you should keep in mind that at this point, we're not talking about phone minutes being bought and sold, only the card itself... just like slurpee syrup, candy bars, etc. around the milwaukee area, you are likely to see cards from radiant telecomm[1]. according to radiant's website, the card I have in my hand offers a rate of 6.9 cents per minute with no access charges or surcharges. in general, you will see cards with advertising claiming all sorts of wonderful rates. the fcc recommends that you call the customer service number on the card[2], which is a good idea. (I'm not slamming radiant telecomm here; but I will point out in a minute why those ads you see next to the card machines aren't completely correct.) the company that generated (made) the card may only be charging you X cents per minute, but there are other people involved that want to get paid. from the fcc: "FCC rules currently require that long distance telephone companies pay phone service providers 24 cents for each call they receive from payphones, except those calls for which the PSPs already collect compensation under a contract. The 24 cents per-call compensation rate is a default rate that can be reduced or increased at any time through an agreement between the long distance company and the PSP."[3] the payphone service provider (PSP)'s cut is paid for by a 'payphone access charge' which comes out of the total value of your prepaid card every time you call the 1-800 number to use your card. the cost of the 1-800 call (whatever the 1-800 provider charges the prepaid card company) comes out of your prepaid card. basically, everyone involved in completing your call gets a piece of the pie through these little extra charges. in the interest of making a profit, the prepaid card company is going to pass on every charge *they* have to pay, *on to you*. essentially, you're buying a $x value card, not a x minutes card. a '2500 minute card' is actually meaningless, because you will never get that many minutes of actual talk time. depending on the type and length of call, you may actually still be saving money (international calls, especially). you also get the convenience of not having to deal with change, portability, and not having a large phone bill waiting at the end of the month. so are prepaid calling cards good, or bad, for users? personally, I like the convenience of not having to have change handy, especially for long distance calls placed across town (sussex to a milwaukee nextel number, for example). they are certainly no worse than local telephone company calling cards that tack on $5.00+ *per call*, plus whatever other charges need to be paid. I suppose it's easier (for me) to use up a $25.00 card and throw it away, then it is to have $25 worth of calling card calls on my monthly phone bill. if you're moving on foot most of the time, carrying several prepaid cards with you doesn't add extra weight, and they can be used to call anywhere. my conclusion is that prepaid cards are pretty useful. just don't get caught up in the advertising, and don't expect to know exactly how many minutes you'll really get. anonymity is an interesting sideline to the use of prepaid cards; if you buy them from an unattended machine, using cash, does anyone know who you are? unfortunately, yes. most places you buy a prepaid card have security cameras that will record your presence, and the act of you purchasing the card. every phone number you call, plus the number of the phone you are calling from, is recorded. for the truly paranoid, stick to carrying a pocketful of quarters. --- [1] http://www.radianttelecom.com/Products01.htm [2] http://www.fcc.gov/cib/consumerfacts/prepaidcards.html [3] http://www.fcc.gov/cib/consumerfacts/Payphones.html [4] http://members.truepath.com/arisetosavings/prepaid.html =[ article: setting up a dialup bbs ]= by laslo it's 2001. broadband internet access is available for $49.95 a month. why should you care about dialup bbs systems? they're dead, right? wrong. it is 2001, and with that comes a wide array of risks if you're into any sort of underground activities. hacking, phreaking, politics, independent news, freedom of speech, anonymity... these are all reasons to set up a system serving a local calling area, with limited access to those you really trust. a local system can give you security (no remote script kiddies) and control (no isp terms of service) while offering you many of the same capabilities as internet based systems. one in particular, an old dusty ware called waffle, will even let you exchange information with the internet when necessary, or set up your own mail and file forwarding network. waffle v1.65 for DOS runs great on an IBM PC XT with 640k of RAM and a 10mb hard disk. in the early 1990's, I ran a waffle bbs that supported a small community of users that dialed in via a local number, plus a few other users that were able to read/post messages on three locally (but not to tbe bbs) networked slackware boxen located several blocks away. at the time, there was no internet connection available. see below: [waffle bbs] | ------dialup-----| | / / | |------------|----------| <- ethernet [linux] [linux] [linux] waffle offers message boards that are divided into two categories: local and usenet, with usenet messages being forwarded via uucp to the next machine, and eventually out to usenet itself. email can be sent to local users, as well as standard internet email addresses (again providing you have some connection to another machine). on my setup, I had one usenet-style message area that was available on all four machines, plus email could be sent to/from any of the slackware boxes or the bbs. waffle's uucp software was able to interface to slackware's built in uucp software with only minor adjustments to chat scripts and crontab entries, and the system worked well. I will leave it to you to RTFM in regards to waffle; if you're at all ok with unix, you will have no trouble with configuring waffle. UUCP is a little bit of work, but it's not hard with patience. take a look at waffle, and use your imagination. on the philosophical side of setting up such a network, if you plan to be underground, why make your traffic available to be sniffed, captured, and archived on the public internet? ---- [1] link to download waffle http://www.simtel.net/pub/pd/52140.shtml [2] UUCP project page http://www.uucp.org [3] wired article on the shutdown of the uucp project http://www.wired.com/news/technology/0,1282,37031,00.html [4] uucp how-to http://www.redhat.com/mirrors/LDP/HOWTO/UUCP-HOWTO.html =[ call for authors ]= the laslocomm.net technical journal is open to ideas from others. if you wish to have an article or column included in a future issue, please send your submission, article idea, or wacked news item via email (plain text is fine, don't *even* send it in word) to webmaster@laslocomm.net or use the submit form at http://www.laslocomm.net/submit.html. =[ copyrights and credits and shouts ]= all copyrights and trademarks mentioned in this issue are the property of their owners. duh. god didn't say anything to moses about taking anyone else's name in vain. thanks to access denied for granting permission to reprint his article. yo: wi2600, dmitry, irc.2600.net, spydir, nipr.mil, twpyhr.com, lee greenwood (I'm proud to be an american, too), tuner/control cleaner, george webb's on bluemound rd. =[ redistribution ]= (c) 2001 laslocomm.net all rights reserved redistribution permitted for non-commercial, personal use