Why does Tencent Dawang Card always display 0m when sending SMS to query traffic?

Tencent dawang card is free of traffic, with an upper limit of 40G. When it reaches 40G, it will automatically turn off the Internet access function and turn it on automatically the next month.

SMS is a part of unified communication service plan. Users can directly send or receive text or digital information through mobile phones or other telecommunication terminals. The number of characters that users can send and receive short messages at a time is 160 English, numeric characters or 70 Chinese characters. Short message 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.

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.