Communication big data itinerary card, commonly known as "itinerary code". It is a free query service provided by the China Academy of Information and Communications Technology (AICT) in conjunction with China Telecom, China Mobile, China Unicom and the three basic telecommunication enterprises to the nation's 1.6 billion cell phone users by using cell phone signaling data obtained through the user's cell phone's location at the base station, which allows cell phone users to query all the cities and towns they have been to in the previous 14 days.

From 20:30 on January 8, 2021, the trip card will no longer mark the names of cities and towns containing medium- and high-risk areas in red, and will change to include medium- and high-risk areas in parentheses after the city name, with the note serving only as a travel reminder, and not associated with health status.

Expanded information:

Communication big data trip card to whether the user in the local stay of four hours, etc. as the main criteria. The city of Beijing has only designated the risk area to a specific building, but why the word "Beijing" has turned red, it is not clear why, and do not yet understand the higher units of the further relevant requirements.

In 2020 this epidemic communication big data trip card played a very positive role, to achieve the purpose of dynamic monitoring of individual trips. However, in reality, the risk area is more and more refined, and the standard of communication big data travel card is still generally administrative units such as prefecture-level cities, its delimitation range is relatively large, the monitoring method is also slightly backward, the future is still further improvement and refinement of the space.