1, the travel code is a communication big data travel card, which is also equivalent to a health code. It is a free inquiry service provided by China Xintong Institute, China Telecom, China Mobile and China Unicom for mobile phone users nationwide160,000. Through this service, mobile phone users can query all the city information they have been to in the previous 14 days.
2. Big data is a free inquiry service provided by 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.