Area code refers to the telephone area code commonly used in the administrative areas of major cities in the world. These numbers are mainly used for domestic and international long-distance telephone access. For example, Chinese mainland area code 86, Beijing area code 0 10, Guangzhou area code 020, etc. When using domestic long distance calls, please dial 0 first and then the area code. It is worth mentioning that people easily confuse concepts and mistakenly think that there is a 0 in front of the area code itself. In other words, because 0 is the only domestic long-distance access code, it is often used side by side with the following area code, so it is a habit. In fact, when dialing back to domestic cities from abroad, the domestic and international long-distance telephone access code is added after China's country code 86, and there is no 0 in front of the city area code. For example, the area code of Chengdu should be 28, not 028.
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 (most of them were regions and few prefecture-level cities). When the authority end is greater than 10, and the local end is less than 15, some areas with less long-distance telecommunications services adopt regional switching centers. For example, Huaihua City, Xiangxi Tujia and Miao Autonomous Prefecture, Zhangjiajie City, Hunan Province, used a regional exchange center with neighboring Chenzhou City and Loudi City, so the area code is four. However, the long-distance network also adopts the "multilevel tandem system".
In 1990s, computer-controlled program-controlled switches were widely used in China. This multi-level tandem system for long-distance calls has become a thing of the past, and calls between local telephone networks can be realized without going through the upper tandem center. However, the area code format of that year still remained, and then the C4 network merged, and the four-digit area code disappeared. In this way, the number resources can be obtained from the second even three-digit area code, ensuring that each municipal administrative unit has at least one three-digit area code. The original vacant number resources, except reserved for Taiwan Province Province, have been used to fill the vacancies of number resources in various places. 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 2006, 5438+0, 18, Hainan Province had merged C3 networks, leaving only 898. Due to the special long-distance dialing method of GSM mobile phone, the area code of Beijing has to be changed to 10.