Need. Beijing latest into the business building need to sweep trip code, now in and out of the public **** places are required to sweep trip code. The full name of the trip code is communication trip big data card, through the trip code, we can see their own trip track in the past 14 days. And through the big data query, but also can be deduced, you in which areas he has how long, whether there is contact with the sick, there is no risk of infection, etc., for the prevention and control of the epidemic is a very effective measure.