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Image:Area code 202.svg|right|The area colored red indicates the geographical region of the District of Columbia, served by area code 202 poly 0 50 49 54 103 84 111 88 101 107 118 130 143 139 179 140 211 188 238 203 260 240 259 248 248 250 255 262 253 357 1 357 Area codes 571 and 703 poly 1 1 0 45 52 48 117 84 109 109 121 127 180 136 199 164 254 112 345 204 264 286 258 358 420 358 420 1 Area codes 240 and 301 desc bottom-left Area code 202 is the North American telephone area code for Washington, D.C.. The area code was one of the original area codes established in October 1947 by AT&T in the North American Numbering Plan (NANP). After the State of New Jersey with area code 201, the District of Columbia was the second Numbering Plan Area (NPA). NPAs that covered an entire administrative region received a code in which the second digit was '0'.〔AT&T, ''Notes on Nationwide Dialing'' (1955)〕 As of 2012, no plans exist to overlay the 202 area code, as NANPA estimates the current supply of numbers is sufficient at least to the year 2019.〔(2011 NRUF and NPA Exhaust Analysis )〕 Washington is thus one of the largest cities where seven-digit dialing is still possible. However, calls are connected if the area code is dialed. There is no provision for long-distance calls within the area code.〔(NANPA Administration System: Area Code 202 )〕 From 1947 to 1990, area code 202 was an unpublished alternate area code for the nearby suburbs in Maryland and Virginia, which were officially in area codes 301 and 703, respectively. This was possible because the entire Washington metropolitan area is a single LATA. Every number on the Maryland and Virginia sides of the Washington metropolitan area was given a non-published alternate number in 202. This arrangement allowed local calls throughout the metropolitan area to be dialed using only seven digits. Also, for example, a telephone number in Kensington, Maryland, that was officially 301-949-xxxx could be dialed as 202-949-xxxx. However, on October 1, 1990, due to pending number exhaustion, the ability to dial the suburbs using area code 202 ended. There is no exchange code protection and local calls between area codes require 10-digit dialing (area code and number, leading ''1'' is not required and is usually not allowed). Continued growth required the 703/540 split in Virginia, the overlaying of 703 with 571 in Virginia, and the 301/410 split in Maryland. Telephone numbers for offices in the United States Congress begin with 202-224, 202-225, 202-226, or 202-228. ==See also== *Area code 710 *List of North American Numbering Plan area codes 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Area code 202」の詳細全文を読む スポンサード リンク
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