Xi 'an Merchants Xi 'an Credit Card Center will have a ring back tone, and banks will generally take the applicant's personal basic information as the main object of investigation, and will strictly implement relevant procedures.

Back tone generally refers to background investigation, also called "verification of proof materials". It is not an investigation in the sense of traditional public security organs, but an action and behavior of verification. By consulting the applicant's former boss, colleagues, educational institutions, referees and other objects, verify the authenticity and validity of the certification materials.