Tianjin, referred to as Jingu and Jinmen for short, is a provincial administrative region, municipality directly under the Central Government, national central city and megacity in People's Republic of China (PRC), a national advanced manufacturing R&D base, a core area of northern international shipping, a demonstration area of financial innovation and operation, and a pioneer area of reform and opening up. Tianjin is located in North China, northeast of North China Plain, downstream of Haihe River Basin, bordering Bohai Sea in the east, Yanshan Mountain in the north, Beijing in the west, and the rest are adjacent to Hebei Province.
The administrative areas under the jurisdiction of Tianjin include Heping District, Hedong District, Hexi District, Nankai District, Hebei District, Hongqiao District, Binhai New Area, Dongli District, Xiqing District, Jinnan District, Beichen District, wuqing district, Baodi District, Ninghe District, Jinghai District and Jizhou District.
A brief history of area code development;
The area code was determined after the Cultural Revolution. At that time, there was no program-controlled telephone exchange, and there were not many municipal administrative units (mostly districts and few prefecture-level cities). When the local unit exceeds 10 but is less than 15, some areas with less long-distance telecommunication traffic share a regional exchange center, such as Huaihua City, Xiangxi Tujia and Miao Autonomous Prefecture and Zhangjiajie City, Hunan Province, which were adjacent to Chenzhou City and Hunan Province.
In the 1990s, computer-controlled program-controlled switches were widely used in China. This multi-stage tandem system for long-distance calls became a thing of the past, and local telephone networks could communicate without going through the next tandem center. However, the area code format of that year was retained. Later, the C4 network merged, and the four-digit area code was gone.
In this way, the three-digit area code with the second even number will obtain the number resources, ensuring that each municipal administrative unit has at least one three-digit area code. Except for Taiwan Province Province, all localities have used the original spare number resources to fill the vacancy of number resources.
Therefore, the numbers after 63x appear in the area codes of Shandong, Guangdong and Yunnan, and the remaining 898, 899 and 890 in the Tibet area code become Hainan area codes. By May of 20001year, Hainan Province had merged with C3 network, leaving only 898 companies. Due to the special long-distance dialing method of GSM mobile phone, the area code of Beijing has to be changed to 10.
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