Generally inquire about the mobile phone cards used in the last 14 days. If you use two mobile phone cards at the same time, then both mobile phone cards can be queried.

The communication travel card is located by the mobile phone signal. The itinerary inquiry service jointly launched by China Information and Communication Research Institute, China Telecom, China Mobile and China Unicom was opened to the public on February 13, and users can inquire about their visits for free within 14 days. The data source of location query service provided by travel card is mobile phone signaling data, which is obtained through the location of the base station where the user's mobile phone is located.

Function of travel code

Communication Big Data Travel Card is a free inquiry service provided by China Xintong Institute, China Telecom, China Mobile and China Unicom for mobile phone users in China. Mobile phone users can query all the city information they have visited in the previous 14 days through this service.

As of March 25, 2020, the cumulative number of inquiries has exceeded 450 million. From 20: 30 on 202118, the city name of the medium-high risk area is no longer marked in red on the travel card, but is marked in brackets after the city name. Precautions are only used as travel tips and have nothing to do with health status.

On March 30th, 20021year, the epidemic prevention health code of the national government service platform has integrated the relevant information of communication big data travel cards, which can show whether the user has been to medium and high-risk areas and other travel information in the health code to help the health code pass through one code.