How to automatically send text messages to dialed customers after the company's landline is connected, and what information is needed?

Please refer to the following items: "On-hook SMS" refers to a product in which a mobile phone user dials Unicom's fixed telephone number, and after the call is over, he will receive a preset SMS from the enterprise, and the SMS sending number is the fixed telephone number of the enterprise. The content of the short message can be enterprise introduction, product introduction, promotion activities, holiday blessing information, etc. , and can be modified at any time. On-hook SMS is mainly accurate advertising business, and its significance to enterprises lies in advertising business, not SMS business. Specific to the local Unicom customer service reply shall prevail.