Why is the icon of SMS always displayed on the prompt bar?

A short message icon is displayed on the prompt bar to remind you that there are unread messages on your mobile phone or that the short message box is full. You can set the automatic cleaning of SMS boxes or set the size of SMS storage. It is not excluded that some mobile phones have color mailboxes. You should look at all these things or set the mailbox to be cleaned automatically, open the short message, select the setting with the menu key, and find the deleted information or the automatically cleaned information (each mobile phone is different, please find it yourself). Select the number of days or days you need (some mobile phones are set to automatically delete the number of days, while others are automatically reset when the number of short messages reaches). After setting, you can determine the maximum storage capacity of information. Open the short message, use the menu key to select Settings, and find the maximum storage capacity of information. I have always set the maximum storage capacity of SMS as the default, and some default only 20 messages. So I set myself as the maximum stored value. How to set it depends on how much you want to deposit. I suggest that it's better to clean up mobile phone messages regularly. The more text messages, the slower the mobile phone runs, which will slow it down. The meaning of short message Short message service (SMS for short) refers to the text or digital information directly sent or received 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. The process of sending and receiving short messages is a telecommunication service in digital mobile communication system. It is a non-real-time and non-voice data communication service to transmit text or digital short messages through the signaling channel and signaling network of mobile communication system. SMS can be initiated by mobile communication terminals (mobile phones), SMS platform servers of mobile network operators, and network service providers (including ICP and ISP). ) interconnected with the SMS platform of mobile operators. In the technical means to realize the function of short message service, sending and receiving point-to-point messages through mobile terminals occupies the mainstream position, but it is not the only form. Fixed telephone, PHS and Internet are becoming new tools and carriers. At the beginning of the development of short message service, the sending and receiving of short messages started from mobile phones, and finally went to mobile phones, passing through GSM network /CDMA network, short message center and other network elements; With the emergence of short message on demand and customized services, mobile phones, Internet sites and short message value-added service systems can send short messages to each other. Internet sites and short message value-added service systems have become new network elements, while GSM/CDMA networks and short message centers still maintain the core position of short message networks. With the emergence of PHS mobile phone based on fixed telephone network in China, the short message service has been extended to fixed network, and the terminal is no longer limited to mobile phone. PHS mobile phones or dedicated fixed terminals can be used as the sender and receiver of short messages, and the network foundation is no longer limited to digital mobile networks such as GSM/CDMA networks. Fixed network can also become the network foundation of short message, and the elements of short message network have changed significantly. With the extension of short messages from mobile phones to PHS and fixed terminals, and from digital mobile communication network to fixed telephone network, people's understanding of short messages is no longer just regarded as the "patent" of digital mobile phones. Business forms are changing, network elements are changing, and information content is rich. There are only two things that remain unchanged in this process: 1, and the length of the message is always less than 140 English or numeric characters, or 2. Short message sending mode-store and forward. When the user does not receive it, the short message will not be lost, but will be temporarily stored in the short message center. When the user logs on to the network again, the short message will be quickly submitted to the user's mobile phone. These innate characteristics make short messages have the advantages of being accurate, reliable, fast and timely, and also make short messages have the basic conditions that affect people's habits.