What's the matter with no sound in SMS?

Turn on mute. In the process of using the mobile phone, after turning on the mute mode, there will be no prompt sound, and there will be no sound when receiving short messages. 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.