Since its launch, the Communications Big Data trip card has become an important tool for epidemic prevention and control everywhere. City names marked with an asterisk indicate the presence of cities containing medium-high risk areas in your itinerary for the past 14 days, but this does not mean that you have actually visited these medium-high risk areas. These notes are only used as indicators of cities with high and medium risk areas and are not related to personal health conditions.

Principle of the travel code:

Using cell phone signaling data, the user's cell phone is located in the base station location to obtain information about the user's location. The big data of communication trip code, by the China Academy of Information and Communication Technology, China Telecom, China Mobile, China Unicom three basic telecom enterprises to use the cell phone "signaling data", through the user's cell phone is located in the base station location to obtain, for the country's cell phone users to provide free query service, cell phone users can be queried through the service, the first 14 days of my visit to all cities and towns information. The service provides free query service to all mobile phone users in China.