What is the difference between the travel codes of two mobile phone cards?

Travel itinerary code records the location according to everyone's mobile roaming records. The rule that a card can have roaming records in different places is to make phone calls in the same place more than twice a day, with an interval of more than four hours! If everyone's mobile phone is dual-card, then the two cards are in different locations. For example, one card is a home card and the other card is in a different place. If people are in different places and don't use their home cards, there may be a problem that the travel code can't find the travel data.

The communication travel card is located by the mobile phone signal. The itinerary inquiry service jointly launched by China Information and Communication Research Institute, China Telecom, China Mobile and China Unicom was opened to the public on February 13, and users can inquire about their visits for free within 14 days. The data source of location query service provided by travel card is mobile phone signaling data, which is obtained through the location of the base station where the user's mobile phone is located.

In order to ensure the continuity of communication, achieve coverage without blind areas and provide better communication service quality, the signals of base stations at the junction of administrative divisions may overlap, resulting in deviation of results. This may happen if the user lives near the city boundary or takes a long-distance self-driving car or train.

Introduction:

"Travel Card" can use this service as long as it has a mobile phone and is a user of any one of the three major operators, namely China Telecom, China Unicom and China Mobile. However, new users can use the service after 14 days.

The "Travel Card" is used to help users who have returned to work prove the areas they have been to recently. Therefore, employers and community management departments can use it when checking the itinerary of immigrants. The "Travel Card" can show that users have arrived in the past 14 days. Visit countries (regions), cities and regions that have stayed in China for more than 4 hours.