Area Code 511 – Zhenjiang, Jiangsu

Geographic Coverage and Administrative Context

Area code 511 is a geographic National Destination Code (NDC) assigned to Zhenjiang, a prefecture-level city in the western part of Jiangsu Province, People's Republic of China. Under the ITU-T E.164 numbering plan, the full international dialing prefix is +86 511. Zhenjiang is a historically and economically significant city located at the confluence of the Yangtze River and the Grand Canal. The code covers the entire prefecture, including the central urban districts (Jingkou, Runzhou, Dantu) and the county-level cities of Danyang, Yangzhong, and Jurong. As a geographic code, 511 is used for fixed-line PSTN services, and its allocation is managed by the Ministry of Industry and Information Technology (MIIT) and the local telecommunications administration.

Dialing Formats and Caller Instructions

For local callers within Zhenjiang, the area code is typically omitted when dialing a local number; the subscriber number is dialed directly. For domestic long-distance calls from elsewhere in China, callers must dial the trunk prefix 0 followed by the area code and the subscriber number: 0 511 XXXX XXXX. International callers should dial the country code for China (+86), then the area code without the leading trunk prefix, followed by the subscriber number: +86 511 XXXX XXXX. For example, a local number such as 8441 0000 would be dialed as 0511 8441 0000 domestically and +86 511 8441 0000 from abroad.

Numbering Structure and Overlay Considerations

Subscriber numbers within the 511 area code are typically 7 or 8 digits long, depending on the specific exchange and the service provider. The total length of a domestic national significant number (NSN) is 11 digits (excluding the trunk prefix), while the international format includes the country code and the NSN, totaling 13 digits when including the +86. As of the current numbering plan, there is no overlay code for Zhenjiang; the 511 code is the sole geographic code for the region. However, with the growth of telecommunications services, the MIIT has implemented number portability for mobile services, but fixed-line numbers generally remain tied to the geographic location.

Service Providers and Usage

Fixed-line services under the 511 code are provided by the three major state-owned carriers: China Telecom, China Unicom, and China Mobile (which also offers fixed-line services). These services are used for residential and business landlines, as well as for broadband and VoIP services that are tied to the physical location. While mobile numbers in China are non-geographic and begin with 13x, 15x, 18x, etc., the 511 code is reserved exclusively for fixed-line and other geographic services. Callers should be aware that some businesses may use 511 numbers for customer service lines, but these are still subject to standard PSTN tariffs.