Under what circumstances does SMS not show delivery?

When the text message was hacked, it did not show that it had been delivered.

Short message is text or digital information sent or received directly by users through mobile phones or other telecommunication terminals. The number of characters that users can send and receive SMS at a time is 160 English or numeric characters or 70 Chinese characters.

On April 8, 2020, China Telecom, China Mobile and China Unicom jointly issued the White Paper on 5G SMS, which made the basic SMS service in China enter a comprehensive upgrade channel, and the traditional SMS will be gradually replaced by 5G SMS (RCS service).

The inventor of mobile phone short message is Finnish. Because Nordic people are sensitive and don't like to express by phone, they invented short message on a whim. Someone on the Internet said that the inventor of short messages was marty cooper, an American who worked for Motorola, but he invented mobile phones, not short messages.

The world attributed the appearance of the first mobile phone in 1973 to marty cooper, the chief designer of Motorola. It was not until nearly 20 years later that the most valuable additional service SMS of mobile phone was published.

1992, Acision company put the first short message service center system into the market. Its initial design purpose was mainly to investigate and improve the reliability of the developing mobile phone market, and then Telenor, a Norwegian local telecommunications company, became the first signing company of SMSC.