The trip code of the foreign place will usually disappear after 14 days. Big Data Communications trip code is one of the information that must be checked to understand the travel situation of people in multiple locations, generally after 14 days will eliminate the previous trip records for coverage of communications, Big Data Trip Card is a trip query service jointly launched by the three major carriers of China Telecom, China Mobile, China Unicom, which can provide users with proof of the regions and domestic cities visited in the past 14 days free of charge.