How to open SMS filtering service by SMS?

hello, telecom users can edit the short message code KTDXGL and send it to 11 to open the short message filtering service.

SMS filtering service mainly aims at spam or malicious SMS harassment, and provides filtering means for users. After subscribing to this service, users can set short message filtering conditions by number, time period and keywords, and the short messages that meet the filtering conditions will be automatically filtered out by the system. In this way, users can reject spam messages and avoid malicious harassment.