The online time inquiry of Shandong health code travel card was launched on March 6, 2020. Communication Big Data Travel Card Inquiry Service Communication Big Data Travel Card is a free inquiry service for 654.388+600 million mobile phone users nationwide, which was obtained by Information China Information and Communication Research Institute in collaboration with China Telecom, China Mobile and China Unicom by using mobile phone signaling data. It was launched on March 6, 2020. Through this service, mobile phone users can query all the city information they have been to in the previous 14 days. 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.