================================================================================ Volume 1, Issue 6, May 1993 NuKE Info-Journal #6 NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE uK E- KE "A guide to the North American Numbering -N E- System" Nu -N uK Nu By KE uK Nowhere Man E- KE -N E-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-NuKE-Nu % Introduction % ~~~~~~~~~~~~~~~~ Recently it was announced that the final available area code (under the current area code format), 610, has been appropriated for use in southeastern Pennsylvania. With this change, all standard area codes for the North American phone system have been exhaused. While the final cutover to 610 will not be for another year, this is a landmark for our phone system. In response to this announcement, I've decided to release various information which I've been gathering about the North American phone system to the general public. I hope everyone finds it of interest. Please note that this article assumes that you know nothing about the North American phone system, so readers from the United States and Canada may find some of the information I present to be rather obvious (what 411 and 911 are, for example, or how various calls are placed by a customer); please bear with me for the benefit of those in Europe, etc., as there's some (in my opinion) very interesting information that I've uncovered about out telephone network. % Background % ~~~~~~~~~~~~~~ The North American phone network is the oldest in the world, yet also uses some of the most modern techniques and equipment. Unlike the majority of phone networks, which cover individual countries, the North American phone system covers the United States, Canada, and most of the Caribbean islands (such as Puerto Rico, Barbados, and so on). While calls between various countries on the North American system are generally billed at international rates, they are dialed like any other long-distance call. The entire North American phone system is assigned the country code +1; hence, it is often refered to officially as "World Zone One." World Zone One is further divided into area codes (three digits), which cover larger regions (states, provinces, etc.), exchanges, also three digits, which cover towns or small parts of a larger city, and subscriber-loop numbers (four digits), which identify a given customer in each phone exchange. Together, these form a ten-digit phone number -- unlike many areas, North American assigns ten digit numbers to everyone, regardless of location (in contrast, the U.K. uses two-or-three digit city codes, an optional exchange [for larger towns] of up to three digits, and four digit subscriber numbers). % Organization of area codes % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The de-facto standards bureau for North America's phone network is Bell Communications Research Inc. (Bellcore). Bellcore was formed by AT&T after it's divestiture in 1984 and provides technical and research support to regional holding companies. Bellcore maintains common standards for the telephone systems, ensures a smoothly operating telecommunications netowork, and coordinates operations during national emergencies. Bellcore assignes all area codes and guides other aspects of the telephone numbering scheme. Area codes, known as Numbering Plan Areas (NPAs) in North America are presently of the form N0X or N1X where N represents a number between two and nine, and X is any number between zero and nine; however, area codes ending in -00 or -11 are reserved for special purposes (see below), and are therefore currently unavailable. Originally, central office (exchange) codes were in the form NNX, which distinguished them from area codes, as only area codes had a zero or one in the second digit. However, with increased demand for phone numbers, most exchanges have changed to the NXX format (ie. the second and third digits of an exchange code can be any number, zero to nine). Naturally this presents problems, as exchanges whose seconds digit is one or zero are now indistinguishable from NPAs. As a result, most areas use "one-plus" dialing: to make a long-distance call you dial one plus the area code plus the local number. Area codes were initially assigned in 1947, with at least one being assigned to each American state and Canadian provice and several being assigned to more populous ones -- in all 86 NPAs were originally assigned. Currently the only exceptions to this "one or more NPAs per state" are in Canada, where 902 serves both Nova Scotia and Prince Edward Island, area 819 covers the eastern Northwest Territories as well as part of Quebec, and area 403 covers Alberta, Yukon and the western Northwest Territories; in addition, the 809 area code covers many locations throughout the Caribbean, from Puerto Rico to the Bahamas to the Virgin Islands to Jamaica. (Note: Midway Island and Wake Island, two U.S. posessions in the Pacific Ocean have just been added to area code 808 [Hawaii]. Prior to this time, they were not direct dialable.) The original proposal suggested that the 86 area codes be assigned in a semi-regular pattern (for example, Canada would have been 915, 914, 913, 916, 917, 918, 919, 910 from east to west by province). This plan was modified to eliminate the confusion caused by "similar" area codes adjacent to each other. A state initially assigned a single area code would have zero for it's NPAs middle digit, while a state with more than one area NPA would have a one as a middle digit. Areas where more inward calls were expected (major metropolitan areas like New York City) received "short pull" area codes like 212, because the dialing time would be shorter (remember, this was in the days of rotary phones) and the mechanical switching equipment would be tied up for shorter periods. For example, New York City received 212 (a total of five pulses), while Chicago and Los Angeles, the next two most populous areas in the U.S., received 312 and 213 (six pulses each), respectively. This went all the way on down to NPA 809, the Caribbean, which required 27 clicks of the rotary dial and would presumably be dialed least frequently. Of course, with the dominance of DTMF dialing, a region's NPA is no longer significant... (As a side note, New Jersey was originally given the area code 201, the smallest [numerically] area code, because Bellcore is headquartered there.) Since the initial assignment, there have been numerous area code splits, where certain telephone exchanges are removed from an area code and placed into a new code. Since 1980 there have been at least twenty such splits. The first split occured in the early 1950s, and the final split will occur when 610 is created in 1994. In the U.S., NPAs were further subdivided into LATAs (Local Access Transport Areas) after the breakup of AT&T in 1984. Before this time, there was no real definitation of what was local and what was long-distance; in order to be fair to communities on state borders, etc. (imagine paying LD charges to call five miles away!), LATAs were created that encompassed "populated areas with common calling needs." All calls made within a LATA are handled by the common local telephone company (New York Telephone, Pacific Bell, Illinois Bell, etc.), which currently subscribers cannot choose (this will probably change in the next few years), while all calls between LATAs are handled by a customer-chosen long-distance carrier (AT&T, MCI, Sprint, etc.) and are subject to federal regulation. A LATA may cover a small area or a whole state; they are usually contained within one NPA, but may cover several (e.g. the Chicago LATA covers all of area codes 312 and 708). As of 1991 there were 196 LATAs (and I believe this will not change). Canada does not currently have a LATA system, though it may soon develop one. LATAs are assigned codes, but these are only for billing purposes, and are not dialed by the customer; in fact, LATAs are transparent to the caller, except for routing/billing purposes. Direct Distance Dialing (the ability to place long-distance calls without going through an operator) first was implemented on November 10, 1951 in Englewood, New Jersey, USA, though it was not wide-spread until the 1960s. There was early use of 11X+ codes for long-distance dialing, but eventually 1+ long-distance dialing became standard. As stated, area codes were assigned in 1947, five years before anyone would need one. Why was it done? I'm not sure. It can only be assumed this was done for 1) future planning and 2) the operators' benefit. (Another odd thing is that 0+ [operated-assisted] dialing became available in 1960, almost ten years after direct-dialing was introduced. Why did they bother? Beats me.) Surprisingly enough, a few tiny areas within the United States and Canada are *still* not direct dialable, but they're in remote regions. This includes some isolated ranches in the Texas desert (Bar J Ranch, Double B Ranch, etc.), bordellos and truck stops in Nevada desert areas (Amargosa, Corncreek, etc.), and some wilderness towns in California within the U.S., and remote resorts in Ontario (Kingfisher Lake and Deer Lake, for example) and isolated arctic villages in the Yukon and NWT (Redknife, Taglu, etc.), in Canada. These areas must be serviced via radiophone, so an operator is required. % Non-standard area codes % ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Certain area codes are not available for normal purposes. These can be generally subdivided into two categories: "Service Access Codes" (SACs), NPAs ending in -00, or "11" services, NPAs ending in -11. Service Access Codes are employed like normal access codes (and are dialed normally), but are not assigned to customers in any one geographic area. Rather, SACs are used for Wide-Area Telephone Service (WATS) by business. Currently, only four SACs are employed, and only three can be dialed by normal customers at the present. 600 ~~~ The 600 NPA is currently reserved for Canadian TWX systems (see below) and ISDN usage. To my knowledge, it is not dialable by normal customers. (In fact, I've seen it used in TV shows for 800 numbers like 555 is used for local numbers [ie: call 1-600-FLO-WERS for a fake flower company, since the real 1-800-FLO-WERS already belongs to FTD Florists, who would probably not appreciate hundreds of crank calls tying up their business line].) 700 ~~~ 1-700 numbers are used for Group Access Bridging (GAB) lines: teleconferencing, EasyLink 700 service, chat lines, etc. (Note the cute little acronym...who says Bell doesn't have a sense of humour?) The most famous 700 service is Alliance Teleconferencing from AT&T, but there are many other chat lines available to those with lots of money to burn. The 700 exchange is also used for AT&T EasyLink 700 service, where a customer gets a phone number that can be rerouted to any phone he visits. For example, if a businessman is traveling around the country, at each hotel he stays at he can dial up an 800 number, enter his phone number and PIN, then the current phone number, and all calls to his EasyLink number ring on the phone line he entered; now the office always knows which number he can be reached at. In addition to GAB/EasyLink services, the 700 NPA is sometimes used to allow intra-LATA calls to be placed via your long-distance carrier. By dialing 1-700-NXX-XXXX you are really calling NXX-XXXX but being billed by your long-distance company instead of the local telco. Not all LD services offer this, though (AT&T, for one, does not, but Telecom*USA does). To find out if this is available from your carrier, either call the long-distance operator, or try calling yourself via the 700 NPA (if it's busy [or your call-waiting beeps] you can use the 700 area; or, you can call your other line, if you have one, or a friend to test this out). 800 ~~~ 800 service was pioneered by AT&T in the 1960s and has since become a world standard, with most countries adopting the 800 area code for toll-free dialing. 1-800 numbers are used by businesses, and, increasingly, residential customers, as a service to clients (or, in the case of home users, to college students, truck drivers, and others who need to call home a lot) -- the business decides which areas it wants to provide 800 access in (home state/province only, nearby states/provinces, a whole region of the country, a whole country, U.S. and Canada, or even international, all at increasing cost), and people in those areas who call the 800 number are not billed for the call: the business is. Each 800 number maps to a normal phone number, and the caller is billed normally for the call, however just before the bill is totaled, any 800 calls are removed from the bill and instead billed to the 800 line's owner. The owner of the 800 line pays a startup charge, a monthly fee, and a fee for every fraction of an hour that the line is in use. (Note that as of May 1, 1993 800 phone numbers belong to the business that operates the line and *not* the phone company. This is a step towards the day where every customer will get a permanent phone number no matter where they move, which company they use, etc. This also means that long-time customers are finally free to leave AT&T without losing their old phone numbers...) Before 800 service, local businesses could provide toll-free service with "Zenith Numbers" (ie. ZEX-XXXX under the exchange- name system). Since "Z" isn't on the phone dial, the caller had to have an operator place the call, which was then billed to the business. (This service is still in use in Canada.) 900 ~~~ 1-900 numbers are infamous as kinky phone sex lines, rip-off astrological recordings, etc.; however 900 service is actually much like 800 service... Nothing about 1-900 service dictates that the caller be charged for the call (though he invariably is) -- the key difference between 800 and 900 service is that 900 lines have much higher call-handling capacity (some 900 lines can receive hundreds of thousands of calls at once without jamming!). In addition, 900 service allows the provider to make the caller pay a portion of the charges. As a result, 900 lines have become pay-per-call lines, where the user is charged $0.25-$50.00 plus per-minute costs to listen to pre-recorded messages, chat one-on-one with some cheap whore, etc. The other group of special "area codes" are the N11 series of NPAs. These numbers are not true NPAs, but rather numbers that Bell has assigned to certain key services (police/fire, directory assistance, etc.) as a service to customers -- you just dial the three digits (or 1+ the three digits in some areas), and the call is quickly completed. The -11 codes include: 011 ~~~ 011 is the international dialing prefix in World Zone One. (Unlike most of the rest of the world, which uses 00 for overseas calls, North America uses 011.) 211 ~~~ This code is no longer in service (to my knowledge), but in "the old days," before Direct Distance Dialing (ie. pre-1960s), 211 called up the AT&T long-distance operator, who would place your long-distance call for you. Naturally, this is no longer needed (operator-assisted calls are placed via the long-distance operator at 00), so 211 is generally not used in most areas (in a few NPAs 211 is a ringback). 411 ~~~ 411 reaches local directory assistance (as if you dialed 555-1212). This operator only gives numbers within your NPA (sometimes in neighbouring NPAs, too); to find a number in a different area you have to dial NPA-555-1212. 511 ~~~ 511 is generally unused, though in a few places it is used for ringback. 611 ~~~ 611 reaches your local telephone company's repair office. You provide the man/lady with your error, and for an outragous fee ($1.15/minute in my area), they'll send out a lineman to (hopefully) find and correct the problem. 711 ~~~ The 711 code is not always available, and it's actions depend on where you live -- in British Columbia, for example, 0+711 is used for mobile service, while in Illinois 711 reaches the emergency bureau as if you dialed 911 (see below). In a few areas 711 is the ringback number. 811 ~~~ In some areas 811 dials the local telco's business office. This code was more universal in the past, as now most areas have moved the business office to a 1-800 number (leaving 811 unused). 911 ~~~ The world-famous 911 code calls up a special emergency center where your call is processed and forwarded on to the appropriate agency (police, fire department, ambulance, etc.). The 911 operators automatically receive your name, phone number, address and other information when you call (computers and ANI do the magic), so be wary of trying to mess with this service (not a good idea anyway, as 911 performs a valuble public service). 911 is not available in all areas (mostly rural areas), so this code isn't universal. % Unusual area codes % ~~~~~~~~~~~~~~~~~~~~~~ At one time, several area codes were used for non-standard purposes. These deserve some special attention. Area codes ending in -10 used to be TWX (TeletypeWriter eXchange) area codes. (TWX was an old system used in the days before faxes and modems. Teletypewriters communicated similar to terminals -- a person on the transmitting end would type a message, and a printer on the receiving end would print it out. This is how telegrams were sent.) TWX area codes were not normally dialable from a regular phone, to my knowledge, and were reassigned to regular telephone service as the demand for new NPAs increased and TWX service was eliminated (around 1990). The TWX NPAs served the following regions: 410 - United States, northeastern region 510 - United States, east of Chicago 610 - Canada [now located at NPA 600] 710 - United States, southeastern region 810 - Mexico 910 - United States, from Chicago westward The other set of area codes that deserves mention are the Mexico access numbers. Mexico is not integrated into World Zone One, and is assigned the country code +52. However, a large number of calls are placed to Mexico from North America, so in the days before International Direct Distance Dialing was universal, AT&T assigned three special NPAs for Mexico. These were not NPAs in the true sense: they mapped to Mexican city codes and local numbers. In addition, they were not dialable from outside of the U.S. and Canada. By 1990 IDDD was available from everwhere in North America, so on February 1, 1991 the codes were released for use as true area codes. These codes were as follows: 706 - Northwest Mexico (Tijuana area) [now northern Georgia] 903 - Southwest Mexico (Guadalajara area) [now northeast Texas] 905 - Mexico City area [soon to be southern Ontario] As you might have noticed, these numbers convieniently map to Mexican phone numbers: 706 was really for 70-6X-XXXXXX, 903 was for 90-3X-XXXXXX, and 905 was for 90-5-XXX-XXXX. All of these map to ten digits, an NPA and local number in World Zone One... The 909 area code was used at one time for the Telenet Communications Data Network, now known as SprintNet. When area codes became scarce, Bell took back the area from Telenet, giving it an "interchangeable" area code instead (see below); I'm not sure which area they received. 909 was chosen, naturally, because it takes the longest ammount of time of any area code to dial on a rotary phone (28 clicks). Since Telenet was to be used by computers, which had TouchTone dialing, this didn't matter... 909 is now being used by Riverside and San Bernadino Counties in southern California (formerly part of the 714 area). Finally, what about the 710 area code? 710 is reserved for telephone company and U.S. government purposes, but little is known beyond that. It *cannot* be dialed from a normal telephone. Most operators deny its existance. Which agencies use it? Why? Is this NPA for special "secured lines?" Is it even used at all? If anyone has more information about this area code, please let me know. % Area code statistics % ~~~~~~~~~~~~~~~~~~~~~~~~ Which states/provinces have the most area codes? Here are the top five: 1. California, USA -- 13 2. New York, USA/Texas, USA -- 9 3. Illinois, USA -- 6 4. Ontario, Canada/Pennsylvania, USA -- 5 5. Florida, USA/Ohio, USA/Michigan, USA -- 4 (Note: After 416 splits, Ontario will be tied with Illinois for 3rd place with six area codes each; Michigan will move up to number four with five NPAs when 313 finally splits. At least ten states and one province have three NPAs.) Which area codes have the most exchanges in them? The top ten are: 1. 212 (New York, USA) -- 705* 2. 205 (Alabama, USA) -- 693 3. 919 (North Carolina, USA) -- 691* 4. 313 (Michigan, USA) -- 688* 5. 416 (Ontario, Canada) -- 680* 6. 215 (Pennsylvania, USA) -- 665* 7. 602 (Arizona, USA) -- 657 8. 206 (Washington, USA) -- 649 9. 708 (Illinois, USA) -- 644 10. 713 (Texas, USA) -- 636 (Note: Starred exchange numbers mean that the NPA is scheduled for a split by 1994 [212 is moving some exchanges to 718 right now].) Which area codes have the fewest exchanges? The top ten are: 1. 807 (Ontario, Canada) -- 105 2. 906 (Michigan, USA) -- 117 3. 302 (Delaware, USA) -- 129 4. 413 (Massachusetts, USA) -- 135 5. 401 (Rhode Island, USA) -- 141 6. 307 (Wyoming, USA) -- 171 7. 607 (New York, USA) -- 176 8. 719 (Colorado, USA) -- 179 9. 802 (Vermont, USA) -- 181 10. 506 (New Brunswick, Canada) -- 182 (Note: 917 [New York pager/celluar service] was omitted because it is growing too fast... It had 104 exchanges as of January, but by April is had 124. By now it surely has more. Besides, I don't like to consider it a real area anyway.) (All exchange data is from April 15th, 1993, so this may have changed by now.) Which area codes have the most unlisted numbers? Well, nine out of the top ten area codes are in California. While most people would probably quickly attribute this to the infamous "California" attitude, it's most likely due to the fact that Pacific Bell offers the lowest rates for unlisted numbers ($0.30/month in California, compared to $1.50/month in Chicago, $1.88/month in New York, and $4/month in Idaho). The ten NPAs with the most unlisted numbers (in percent of total numbers) are: 1. 702 (Las Vegas, Nevada, USA) -- 64.6% 2. 209 (Freson, California, USA) -- 63.1% 3. 213 (Los Aneles, California, USA) -- 61.7% 4. 510 (Oakland, California, USA) -- 61.6% 5. 408 (San Jose, California, USA) -- 60.2% 6. 916 (Sacramento, California, USA) -- 59.8% 7. 909 (Riverside, California, USA) -- 57.7% 8. 818 (Anaheim, California, USA) -- 57.1% 9. 619 (San Diego, California, USA) -- 56.5% 10. ??? (Bakersfield, California, USA) -- 55.2% Finally, which areas were considered "the most important" when area codes were handed out; in other words, which areas were assigned the NPAs which required the fewest number of clicks on a rotary phone? The top five are: 1. New York City -- 5 2. Chicago/Los Angeles -- 6 3. Dallas/Detroit/Pittsburgh -- 7 4. Philadelphia/St. Louis/Boston/Austin -- 8 5. Cleveland/Syracuse/Milwaukee/Minneapolis -- 9 (This assumes the original area codes as assigned in the fifties, ie. 212 covers all of New York City, etc.) % Assignment of exchanges % ~~~~~~~~~~~~~~~~~~~~~~~~~~~ When the telephone was first introduced, central-office operators sat at switchboards, completing connections in response to spoken requests. There were few enough phone lines so the operator simply knew where to plug in for the call. That began to change during an outbreak of the measels in Lowell, Massachusetts, in 1879. The town doctor, feared that if all four operators fell ill, their substitutes would have trouble connecting people unless every line got a number. The idea quickly caught on. In the 1880s telephone service quadrupled in the nation's settled areas. Cities soon had not only a central office and phone numbers but exchanges in other parts of town, so callers now asked for Main or Central plus the subscriber's several-digit number. Branch exchanges usully took their names from their relative geography, street names, or names of neighborhoods. Bell devised phonetic tests to help make sure only easily understood names were chosen. When neighborhood and street names started to run out, the Bell System recommended new names, like Evergreen, Lakeside, Poplar, and Walnut. By the time dialed calling was introduced in the Bell System in 1921 the exchange name were so ingrained that Bell Telephone kept them on. William G. Blauvelt of AT&T had divided the alphabet into groups of three letters for each of the dial's openings in 1917. Z was omitted because, well, it was the last letter; that left an odd letter to eliminate. It came down to Q and X, the two most infrequent letters in English, but Bell finally decided to keep X, since Q could only be followed by U, limiting the number of possible exchange names. And because a single phone-number pulse could be transmitted when the receiver lifted or the finger wheel was jarred, no calls would be initiated until a pulse signal of at least two was received; thus the number one got no letters attached to it. Dialing swept the nation, but only large cities used exchange name dialing; in small towns one still had only to dial a three- or four-digit number. (As a side note, why was it that subscriber numbers were never more than four digits? It's a carry-over from the early days before direct dialing. It was determined that an operator could not reach more than 10,000 plugs without getting up from her seat...) Seven-digit numbers became standard only after World War II. New York City had pioneered them in the early 1930s when it began inserting an "exchange-designation number" after the two-letter exchange prefix (for example, you used to dial RA6-9999 for the RAndolph exchange in Chicago, with six as the "exchange-destination number"). By the mid-1950s all other major cities were converted to this system, replacing such combinations as Chicago's three letters and four digits, Cleveland's two letters an four digits, and Dallas's one letter and four digits. In 1961 Bell Telephone announced that it would phase out exchange name dialing city by city. Pittsburgh and Cincinnati began converting in 1962; Philadelphia and Seattle were the last to change, in 1978. The classic combiation of two letters and five numbers was a fully national standard for less than a decade. The two-letter-five-number system was also used in Canada, though I'm not sure how widely. Vancouver, British Columbia was one city to use this system, though I don't how many others did. (Anyone have any information about this?) All-number calling was introduced for several reasons. Mainly there weren't enough workable letter combinations. Exchanges like 571 had stayed unavailable because letters like JKL (5) and PRS (7) wouldn't combine. All-number calling also eliminated hard-to-spell exchanges, prevented mix ups between similar leters and numbers like O and 0, and made possible direct dialing from Europe and other parts of the world, where most phones never had letters on their dials. For the benefit of those outside of North America, I have included a diagram of how our phone pads are layed out and which letters are assigned to which key: ÚÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄ¿ ³ 1 ³ 2 ³ 3 ³ ³ ³ ABC ³ DEF ³ ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´ ³ 4 ³ 5 ³ 6 ³ ³ GHI ³ JKL ³ MNO ³ ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´ ³ 7 ³ 7 ³ 8 ³ ³ PRS ³ TUV ³ WXY ³ ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´ ³ * ³ 0 ³ # ³ ³ ³ OPER ³ ³ ÀÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÙ (Note: the zero key is marked "OPER" because dialing zero will summon the local operator. Zero and one have no letters officially assigned to them. Some people like to claim that one is "Q" and zero is "Z", but I have never seen one or zero used in that fashion before.) Each area code has certain exchanges set aside for special purposes. These exchanges are: 555 ~~~ Local directory assistance. Dialing NPA-555-XXXX will get you directory assistance for the given area. This is why most phone numbers in movies and TV shows are 555-XXXX or KLondike-5 XXXX... People whose numbers were used in movies, etc. complained to the studios after getting hundreds of calls from losers asking for James Bond or whatever. (One family's phone number appeared on the cover of a heavy metal album and is now suing the band after receiving thousands of threatening phone calls from fans.) This use of 555-XXXX is purely a voluntary thing; a long time ago Bell was able to reserve certain exchanges throughout the country that producers could safely use, but with a shortage of telephone exchanges they had to stop this practice. 950 ~~~ Used to access other long-distance services. This is called Feature Group B equal access. To use the service you call their 950 number (which is a free call), then enter your multi-digit PIN, then dial the number you wish to call. Almost all areas now have Feature Group D service (Equal Access), where you select an alternate carrier and then use it normally, like you used to use AT&T (ie. just dial 1-NPA-NXX-XXXX). Currently 950s are only used in the U.S., but they are reserved for future use in Canada and will probably soon be utilized, given the recent Unitel decision. Currently Canadian callers must use local dialups for independent long-distance carriers (called Feature Group A, long phased out in the United States). (In the U.K. Mercury uses a similar setup. Mercury phones are equiped to pulse dial 131, enter the customer's ten-digit PIN touch-tone, then enter the number they're trying to call, all automatically. This is sort of like 950 access...) 958 and 959 ~~~~~~~~~~~ These exchanges are usually reserved for plant testing. In some areas they may be used for normal service. In most areas other exchanges are used for testing, too. 976 ~~~ 976 numbers are like local 1-900 numbers. They are billed on a per-minute basis, but are usually much less expensive than 900 calls (not more than a dollar or two at most per minute). 976 can usually be blocked (like 900 numbers), sometimes for a fee. In some areas the telephone company has other exchanges set aside for 976-type usage; for instance in Pennsylvania the telco has reserved the 556 exchange for this purpose, and in Texas 703 is used. Sometimes these other exchanges must be specifically requested by the customer to be dialed (in other words they default to blocked). 844 ~~~ The 844 exchange used to be used for time (it was TIme-4 under the old exchange-name system), but the telephone companies figured why give away this service for free when you can charge $0.50 via a 976 number. Now time is generally found at NPA-976-1616, and the 844 exchange is available for normal usage. (Interesting note: in the San Francisco Bay area [408, 415, 510, 707], you can get the time by dialing "POPCORN", billed as a local call. In New York and Boston, the number used to be "NERVOUS.") 936 ~~~ Like 844, the 936 was once used for pre-recorded messages, only 936 was used for weather announcements (it was WEather-6 in the old days). This, like time, has been moved to a 976 service in most places, usually at NPA-976-1212 (and they throw in obnoxious ads to boot!). Now 936 is usually just a normal exchange. % Phone capacity % ~~~~~~~~~~~~~~~~~~ The original design of telephone numbers was: (NBX) NNX-XXXX. In theory, this gives: N B X N N X X X X X 8 * 2 * 10 * 8 * 8 * 10 * 10 * 10 * 10 * 10 = 1.024 billion numbers However, as some area codes and exchanges are reserved for special purposes (such as 411, 555 exchange, etc), the total possible number of telephone numbers was somewhat less. As the exchange codes in some area codes were used up, some central offices started using the NXX format, where the middle digit can then be a zero or one; this began in New York and Los Angeles and is now used in almost every area code. Now, telephone numbers look like this: (NBX) NXX-XXXX. This gives a potential of: N B X N X X X X X X 8 * 2 * 10 * 8 * 10 * 10 * 10 * 10 * 10 * 10 = 1.28 billion numbers However, codes like 411 and 611 would not be assigned because they will still be needed for services such as directory assistance and repair. Nevertheless, some unused N11 codes like 211 may be found in some area codes as active exchanges. It's also not a good idea to assign the home area code (or nearby area codes), as this could cause confusion. Going from NNX exchange codes to NXX only represents a 25% increase in the total theoretical amount of telephone numbers, and not all area code regions are expected to run out of exchanges. The ultimate goal is not only to use area codes for exchanges codes, but to use exchanges codes for area codes also. This means that telephone numbers will ultimately look like this: (NXX) NXX-XXXX. This gives a potential of: N X X N X X X X X X 8 * 10 * 10 * 8 * 10 * 10 * 10 * 10 * 10 * 10 = 6.4 billion numbers With a five-fold increase in the number of possible area codes, there should be plenty of room to grow for some time. % Placing calls % ~~~~~~~~~~~~~~~~~ Basically, all calls within an area code will ultimately be dialed in one of the following ways: 1) dial seven digits; 2) dial one plus home area code plus the local number; or 3) dial one plus the seven digit number within area code, then wait for a few seconds to time out. One alternative not mentioned in official documents (for touch tone phones) is to use one plus seven digit number in home area code then pressing the pound key, with the pound key terminating the dialing (as in international dialing). * "1+" is generally used for direct-dialed long distance calls within North America, especially calls outside the local area code. Sometimes intra-LATA calls must be dialed 1-NXX-XXX or even 1-NPA-NXX-XXXX if they're outside your local calling area. Yep, unlike almost all of the rest of the world, World Zone One uses 1 for DDD calls instead of the internationally-standard 0. * "0+" is used to dial operator-assisted or automated credit card calls within North America. After 0 + (area code) + number are dialed, a prompt tone (same tones as a dial tone, but for a very short duration) will be issued, then one of the following actions will be taken: 1) wait for a few seconds, then an operator will come on line; 2) dial "0" to get the operator immediately (for a collect or person-to-person call, etc.); or 3) dial the telephone company credit card number for billing purposes. It is unclear what will happen in the cases of automated collect calls, as to what kinds of dialing would be standard in that case. In my area, a computer voice system prompts you for your name, then dials the number and says "You have a collect call from [your three-second message]. Press one to accept the charges or two to reject the call" (or something very close to that). Of course, this system is open to abuse: probably the most collect calls are made from a Mr./Ms. "Call me back at NXX-XXXX", etc... Also, this system is only used for local calls. * Dialing "0" and waiting will get the local area operator. * "00" is used in the U.S. to get the operator for a default long distance carrier. This is used as most long distance companies have their own operators. A single "0" digit will call up the local operator (with the local telephone company as opposed to the long distance company). * "01" is used for overseas calls. "01+" indicates an operator-assisted or automatic credit card call, while "011+" indicates a direct-dialed overseas call. "010+" is reserved for some unspecified future use. * "10XXX+" is used in the U.S. to indicate which long distance carrier to use in a situation known as "equal access." This allows a telephone subscriber to select a long distance company for a particular call. For instance, "10288+" gets AT&T (288 is ATT...), while "10222+" gets MCI and "10333+" selects U.S. Sprint. After this code, a 1 or 0 is dialed (to indicate direct dial or operator-assisted call), then the number to be called. With this system you can place a call via another carrier if they offer lower rates, etc. for that particular call. You get a separate bill in a month or two. 10000 is not available for assignment. 10001 - 10099 are reserved for restricted purposes. 10100 - 10199 are reserved for international carriers. 10200 - 10999 are assigned to standard long distance carriers. Canada doesn't have to worry about this code yet, though given the recent changes in long-distance regulation, it's likely that they will adopt a U.S.-style system soon. * "11+" is reserved for special calling services like call-waiting functions, etc. For instance, "1170" is used to disable the call-waiting. The asterisk or "star" key ("*") can be used instead of the "11" prefix on touch-tone phones. The current special calling codes on many local telephone systems are: *57 - call tracing request (some systems use this for call back) *60 - call blocking activated *61 - priority ring activated *63 - select call forwarding activated *66 - repeat dialing activated *67 - call number ID blocking (must be dialed before each call) *69 - call return activated *70 - disable call waiting *71 - three-way calling according to usage *72 - enable call forwarding *73 - disable call forwarding *74 - modify speed calling directory entry (for 8 # service) *75 - modify speed calling directory entry (for 30 # service) *76 - call pickup *79 - ring again *80 - call blocking disabled *81 - priority ring disabled *83 - select call forwarding activated *86 - repeat dialing disabled *89 - call return disabled % International dialing % ~~~~~~~~~~~~~~~~~~~~~~~~~ International Direct Distance Dialing (011+/01+ dialing) began in 1970 between New York and London, and has since become available in all service areas in North America. Over 99% of the world's telephones are reachable from the United States and Canada. According to AT&T, the only areas which require operator assitance to reach are: Afghanistan, Burma, Cuba, Easter Island, Laos, Niue, Norfolk Island, Somalia, Spanish Sahara, Sudan, Tuvalu, Vanatu, Wallis and Futuna, and Yemen. From Canada, calls can direct-dialed to Cuba and Burma (the U.S. government doesn't permit any calls to there, even though the capability exists). North Korea cannot be dialed at all, period, even with an operator; not only do they have a primitive phone system and are politically shunned, they also just changed everyone's phone number, so no one can dial in and spread evil Capitalist propaganda. (There are no phone books in North Korea -- that's classified information. Seriously.) As you can see, most of the non-direct-dialable numbers are small Pacific islands; these calls aren't direct-dialable because the only trunks to these countries are generally to Australia or other Pacific countries, and AT&T is only allowed to use the trunks for an hour or two each day. Other countries just have phone systems in such awful condition that they can't be dialed easily (Laos, Sudan, etc.), while Cuba and Burma are banned in the U.S. for political reasons. Within a few years, the capability to direct-dial all telephones in the world should exist. Already IDDD exists to certain research bases in Antarctica, Mongolia, and other places you'd never even *want* to call. It's only a matter of time, now... % The future of World Zone One % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ On January 1, 1995 all telephone systems are expected to change their equipment over to allow for new "interchangeable" area codes (area codes whose second digits are not one or zero). This date was originally to be July 1, 1995 but was moved up to January because of increasing demand for phone numbers due to fax, modem, and cellular phones. The initial set of new area codes will take the form NN0, or those numbers ending in zero. This means that areas codes that do not have exchanges ending in zero (or only a few NN0 exchanges that could be renumbered) can still be able to tell the difference between an exchange and an area code by looking at the first three digits. The new NN0-type area codes will be assigned starting with these first few codes (in order): 260, 480, 520, 590, 650, 220, 250, 490, 660, 680, 720, 730, 850, and 940. The 970 NPA will be reserved for phone testing purposes, and will not become and area code. New area codes may be assigned as follows: geographic codes will use N2X and N3X, N4X through N7X will be used for expansion, and N8X and N9X will be used for non-geographic codes. (In this notation N represents a digit from 2 to 9, and X represents any digit.) Thus, area codes like 223, 734, or 520 would be geographic codes under the proposal, while area codes like 987, 294, or 780 would be non-geographic (like 700/800/900 numbers are now). This middle digit of the area code is referred to as the "B" digit, thus the B digit indicates a new geographic or non-geographic code. As the initial set of geographic or non-geographic codes are used up, expansion takes place by using the nearest available expansion set. Thus, N4X codes are next in line for geographic codes expansion, while N7X codes are next for non-geographic expansion. Ultimately, expansion to more digits will be needed in the distant future, and it is proposed that either the N5X or N6X codes can be used to provide for "expansion" codes to set up a numbering plan of more than ten digits. In addition to the new area codes, the Carrier Identification Code format of 10XXX+ will be expanded to 101XXXX+ in the near future, because nearly all of the 10XXX codes are assigned at this time. On December 31, 1996 (referred to as "Time T"), there will be an expansion of the maximum international number length from twelve digits to fifteen digits, according to a CCITT recommendation. Already one country has moved to fourteen digit numbers, and more such plans are likely in the future; in order to continue to permit direct dialing to such countries, the maximum number of digits allowed for IDD calls must be increased to at least fifteen. Also, it has been recommended that the North American phone system evolve to ten-digit dialing for station-to-station (network based) calls, including local calls. The idea is to start in the metropolitan areas using "overlay" NPA codes like New York and perhaps other areas soon. It is also proposed that 1+ be eliminated as a long-distance access prefix; in other words, any call in North America would consist of ten digits, whether local, long distance, or to an 800/900-type service. In effect, everyone will have a ten-digit phone number, instead of a seven-digit phone number and a three-digit area code, as under the current plan. Who will get the first interchangeable area code? No one knows for certain, but by observing number of exchanges in each area we can make some educated guesses. Alabama (205) and Arizona (602) both will need new NPAs very soon, as will 206 (western Washington), 703 (Houston area) and [gasp!] 708 (suburban Chicago). One of these five areas will almost certainly get the first code. Some claim it will be 708... An Illinois Bell operator denies this (but remember, this is an IBT operator here, not someone who knows what they're talking about). There is also a rumour that the next split will occur somewhere in Florida, though this seems unlikely as none of Florida's NPAs are running out of numbers and other areas need them much more urgently. Only time will tell. % Conclusion % ~~~~~~~~~~~~~~ Well folks, I hope this information has been of use to you. The telephone system can be a fascinating thing (and I'm not just talking about phreaking here), and I encourage you to learn more on your own. Also, look for more articles about the world telecommunications network in future NuKE InfoJournals. I'd also like to take the time to give credit where credit is due: some of the information in this article was gleaned from the comp.dcom.telecom newsgroup on the Usenet and the Telecom Digest archives at lcs.mit.edu, with other bits coaxed from IBT and AT&T operators, borrowed from other text files, and written from personal knowledge and outside research. Enjoy, everyone. Nowhere Man/NuKE ===============================================================================