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From: Mark J. Cuccia <mcuccia@mailhost.tcs.tulane.edu> As we now begin the month of October 1997, it was sometime during October fifty years ago (in 1947), that the original area code format was 'finalized' by AT&T. Thus, the North American Numbering Plan was born. There _were_ two preliminary plans of assigning area codes. There was a plan indicated as a map of the US in 1945 in issues of both {Bell Laboratories Record} and {Bell System Technical Journal} magazines, in articles on future automated toll dialing and switching - first to be dialed by operators and later by customers. The 1945 map indicated the (continental) US only, and indicated some 60 individual regions. No codes were shown in the regions in the map -- only the possible boundaries. Canada wasn't even indicated on the 1945 map in the Bell magazine articles, although one of the articles did indicate 7-digit (2L-5N) dialing across NPA boundaries with 'protected' central office digits where a metro area straddled an NPA boundary, and an example cited in the article indicated that Windsor ON (Canada), across the river from Detroit MI (USA) could be such a 'protected' 7-digit (2L-5N) dialing situation. Another proposal was from 1946/47 would have all of the area codes in a particular state be from a range of consecutive codes: i.e. New York state would have used area codes 212, 213, 214, 215. However, at some point in 1947, Bell Labs and AT&T decided to change that plan, and instead issued the 'final' plan which has been built-on for the past half-century. I only know that this final plan was issued in October 1947, but I don't know which particular date in October that a possible memo was released by AT&T regarding the nationwide US/Canada numbering plan. I had posted two articles to TELECOM Digest in 1996 on the preliminary but never adopted area code plans. In April 1996 I posted a brief article on the 1946/47 plan where a state with multiple NPA codes would have had all of its codes from a range of consecutive codes. And then in mid-December 1996, I posted a longer article on the development of Operator Toll Dialing and its extension into customer DDD (Direct Distance Dialing), and included a list of the 60 possible regions (states, groups-of-states, portions of states) from the 1945 map of possible future area codes. As for the 'final' plan issued in October 1947, here are the charts showing the assignments. Linc Madison's website also has a map of the US/Canada showing the 1947 assignments: http://www.best.com/~eureka/telecom/map_1947.html N0X Form (States/Provinces with only ONE code assigned) (40 codes assigned) 201 NJ 301 MD 401 RI 501 AR 601 MS 701 ND 801 UT 901 TN 202 DC 302 DE 402 NE 502 KY 602 AZ 702 NV 802 VT 902 mrtm.prv. 203 CT 303 CO 403 AB 503 OR 603 NH 703 VA 803 SC 204 MB 304 WV 404 GA 504 LA 604 BC 704 NC 205 AL 305 FL 405 OK 505 NM 605 SD 206 WA 306 SK 406 MT 207 ME 307 WY 208 ID N1N Form (States/Provinces with several codes assigned) (46 codes assigned) 212 NY 312 IL 412 PA 512 TX 612 MN 712 IA 812 IN 213 CA 313 MI 413 MA 513 OH 613 ON 713 TX 913 KS 214 TX 314 MO 414 WI 514 PQ 614 OH 814 PA 914 NY 215 PA 315 NY 415 CA 515 IA 715 WI 815 IL 915 TX 216 OH 316 KS 416 ON 616 MI 716 NY 816 MO 916 CA 217 IL 317 IN 517 MI 617 MA 717 PA 218 MN 418 PQ 518 NY 618 IL 319 IA 419 OH Note that in 1947, there were _no_ area codes assigned from the N09, N00, N10, nor N11 ranges. The N11 range is still unavailable for NPA assignments, since the eight N11 codes are reserved or used for local 3-digit service codes. The N09 range of area codes were first assigned in 1957. The N10 range of area codes were assigned to automated/dial TWX (Teletypewriter) service beginning in 1962, and continuing through circa 1982. Although AT&T turned (US) TWX service over to WUTCO in the early 1970's, it wasn't until the early 1980's when WUTCO began to switch and route (US) TWX on its _own_ network instead of over the Bell-System's DDD Telephone Network. And although TWX still exists (WUTCO transferred it back to AT&T circa 1990/91), it is handled via a separate network, not 'directly' associated with the AT&T regular telephone long-distance network, and still uses numbers of the N10 form. Therefore, beginning around 1991, the N10 format as area codes were assigned for regular (POTS) telephone services. The N00 format was first assigned for SACs (Special Area Codes) around the mid-1960's, with 800 being the first N00, used for InWATS (Inward Wide-Area Telephone Service), aka "Toll-Free" called-party pays. Note that there were 86 codes assigned to the (at that time) 48 states of the US, including Washington (DC), as well as the ten provinces of Canada. Alaska and Hawaii weren't even states of the US at that time, nor were they even indicated as even being (or intended to be) a part of the US/Canada area code format. Canada's two northern territories, Yukon and the Northwest Territories, weren't indicated as being a part of the area code format, neither. And while Mexico had been 'pseudo' NANP at one time (access to Mexico City from the US was dialable 'as-if' it really were part of the NANP switching/routing network) ... and for some time, certain towns along the extreme northwestern border of Mexico were numbered and dialed _and_ switched/routed as a part of the NANP/DDD network ... Mexico was _not_ shown in 1947 to be intended as part of the NANP. None of the Caribbean was indicated to be a part of the NANP in 1947. Area Code 809 was first reserved/assigned to the Caribbean/Bermuda area in 1958. Customer dialing between the Caribbean and the US/Canada began to be introduced in the mid-to-late-1960's, and continuing through the 1970's and 80's. Newfoundland wasn't yet politically part of Canada in October 1947, but it does seem possible that the original NPA 902 (which at that time also served New Brunswick, in addition to Nova Scotia and Prince Edward Island) also served Newfoundland/Labrador. In the mid-1950's, NB and NF/LB split from 902 (which was retained for NS/PEI), into their own 506; and then in 1962, NF/LB split off from 506 (which was retained for NB), into its own 709. Also note the original intent was that N0X format codes (N01 through N08) were assigned to states/provinces which needed only one area code, and that N1N format codes (N12 through N19) were assigned to states and provinces which needed two or more area codes. That original assignment plan was abandoned in the early 1950's, when assignments of new area codes were beginning to increase. And, note that short 'dial-pull' (lower numerical) area codes were assigned to the more populated areas, due to the number of dialpulse (rotary dial) CPE and switching equipment in existance in 1947. Such shorter dial-pull area codes have fewer dial-pulses, and had been desirable for assignment to such populated areas which would have more incoming traffic than less populated areas. New York City with 212 Los Angeles with 213 Dallas with 214 Philadelphia with 215 Chicago with 312 Detroit with 313 St.Louis with 314 Pittsburgh with 412 etc. As for the 'single-NPA' states, they had N0X format codes. And even though the middle-digit '0' is longer to dial with ten dialpulses, the N0X area codes were assigned such that populated areas had shorter-pull, fewer-dialpulse digits for the first and third digits (even though the middle-digit '0' has ten total dialpulses): 201 for New Jersey 202 for DC 203 for Connecticut 301 for Maryland 302 for Delaware 401 for Rhode Island These are all locations in the northeast or mid-Atlantic area, with rather large metro areas, suburbs, etc., and thus a larger incoming traffic volume. Note that rural Idaho has 208, a longer-pull code. Also note the large number of codes which were unassigned in 1947, which are from the longer dial-pull ranges. While the area code format was 'finalized' in October 1947, customer (and even operator) use of area-codes for long-distance dialing was _QUITE_ limited. The area code format was a planning for the future, so that every telephone line in the US and Canada would have its own unique and distinct telephone number, for easy dialing and routing, first by operators, and later by customers, at later dates, as new automated toll switching (and ticketing) equipment was placed into service, throughout the US/Canada telephone network. Over the past fifty years, the NANP has had more codes assigned. First there were many codes assigned throughout the 1950's and early 1960's, due to the postwar economic and suburban 'boom', as well as the introduction of automated customer long-distance dialing (DDD) in addition to conversions of many manual local exchanges into dial central offices. More customers and lines means more central office codes. And as more central office codes are assigned, eventually new area codes need to be created, usually by a split. Sometimes, new area codes were created in the 1950's and early 1960's due to more efficient trunking requirements as customer DDD was being introduced. In the early 1960's, various conservation plans were being developed to allow N0X/N1X format codes for local central office codes (to be needed in some large populated areas, sometime by the mid-1970's), and for NNX format codes to be used as area codes, sometime by the mid-to- late-1990's. So-called 'interchangeable' NPA codes (NNX format) have indeed been introduced beginning in 1995, and have been assigned at rates never previously seen, surpassing the early rush of area code assignments in the 1950's and early 1960's. Our ten-digit numbering scheme (NXX-NXX-xxxx) in the NANP is expected to exhaust all available (POTS) area codes sometime in the first-half of the 21st Century. At first it was estimated to happen by 2050, but because of the current rate of assignment of NPA codes, some have pushed that date earlier to 2010. However, if local number portability amongst the competitive local telcos is properly introduced over the next ten years, or if central-office-code sharing takes place among the various competitive telcos, it may be possible to reduce the rate of area code assignments. There are frequently questions as to why so many countries or territories are included in a single numbering plan (CCITT/ITU Country Code +1), rather than the US, Canada, and each individual Caribbean island each having unique/distinct country-codes. In 1947, much of Canada's telephone industry was directly associated with the US telephone industry. AT&T did own a portion of Bell Canada; and AT&T's Western Electric, along with Bell Canada, owned Northern Electric (later known as Northern Telecom, now known as Nortel). The Caribbean was intended to be added in 1958. Plans to incorporate Mexico into the DDD network also existed since the late 1950's, and were first introduced around the early-to-mid-1960's. The CCITT/ITU plans for country-codes for each telephone country/network in the world wasn't really introduced until around 1964 (although there was a preliminary 1960 plan for country codes for Europe, North Africa, and nearby Asian countries). In closing, while there were 86 area codes assigned for the NANP in October 1947, fifty years later, on 1-October-1997, I am counting at least 212 active "POTS" (non-SAC) area codes in the NANP, even if only in permissive dialing. And the increase in new NPA codes is far from over or even slowing down. NWORLASKCG0 (BellSouth #1AESS Class-5 Local "Seabrook" 504-24x-) NWORLAIYCM1 (BellSouth-Mobility Hughes-GMH-2000 Cellular-MTSO NOL) NWORLAMA0GT (BellSouth DMS-100/200 fg-B/C/D Accss-Tandem "Main" 504+) NWORLAMA20T (BellSouth DMS-200 TOPS:Opr-Srvcs-Tandem "Main" 504+053+) NWORLAMA04T (AT&T #4ESS Class-2 Toll 060-T / 504-2T "Main" 504+) JCSNMSPS06T (AT&T #5ESS OSPS:Operator-Services-Tandem 601-0T 601+121) MARK_J._CUCCIA__PHONE/WRITE/WIRE/CABLE:__HOME:__(USA)__Tel:_CHestnut-1-2497 WORK:__mcuccia@mailhost.tcs.tulane.edu|4710-Wright-Road|__(+1-504-241-2497)