Is it accurate to send SMS delivery report to China Unicom?

Not accurate. Zhongguancun online website information shows that sending information from mobile phone card to Unicom mobile phone card involves the interconnection between mobile company and Unicom company. After the short message is sent, it needs to be transferred to the base station of another company through the channel. If the channel is busy, there will be delay or even information loss. Once the SMS is sent, the base station will send back the delivery report, which shows the information received by the base station, not the communication equipment of the other party.