What is the business of hanging up SMS? Can the 400 number be opened?

On-hook SMS refers to the information service service that the called user will send a SMS with the called user's number to the calling user's mobile phone after the calling mobile phone user hangs up. In this service, the called user can customize the sending strategy of short messages, such as sending content, sending frequency, sending time period, blacklist, suspension of activation, etc. At the same time, the called user can manage all incoming mobile phone numbers in groups and send short messages to these mobile phone numbers in groups. B. At present, the on-hook SMS function cannot be realized on the 400 telephone of Telecom. (For example, the 400 number service is opened on the user's fixed telephone number, and this fixed telephone number can handle the on-hook SMS service. After processing, dial this fixed phone number, and the other party can receive the text message, but dial 400. ) For more service benefits, click on "official website" customer service 22 1 below to answer your questions.