What does "use USSD" mean on the mobile phone?

USSD (unstructured supplementary service data) service is a new interactive session data service based on GSM mobile communication network, and it is a new value-added service introduced by GSM mobile communication network after short message service.

The common feature of USSD service and short message service is that they both use signaling channel of GSM mobile communication network to transmit data, that is, USSD data is transmitted on logical channel using independent dedicated control channel (SDCCH) or fast associated control channel (FACCH), while short messages are transmitted using signaling channel in wired resources of GSM mobile communication network. USSD does not directly occupy the voice channel of the wireless terminal. In the non-call state, USSD and SMS SM use the same independent dedicated control channel (SDCCH), and the transmission rate is about 600 bit/s. In the call state, USSD uses fast associated control channel (FACCH), and the transmission rate is about 1000bit/s, which is about five times faster than SMS SM using slow associated control channel (SACCH).

The main difference between USSD service and short message service is that short message service SMS adopts store-and-forward mode, while USSD service system adopts connection-oriented interactive session mode and provides transparent channel, which is an ideal carrier of session service.

USSD only needs a little resource overhead in wireless. In addition, due to the interactive connection-oriented bearing characteristics of USSD, it can also be used as a good bearer for WAP, and the combination of USSD and WAP will also bring new business development opportunities for the mobile Internet.

USSD service usually has faster response speed and better real-time performance than short message service. In addition, the interactive conversation ability of USSD can be used, which is not only superior to SMS system in business development, but also mobile service operators can make corresponding services that meet the needs of local users through USSD with little impact on the original settings.

It is worth mentioning that USSD service and SMS service, as two mobile value-added services, have their own characteristics and can complement each other. And can realize seamless integrated application. SMSC and USSDC, the short message service centers in our company's comprehensive platform series of China merchants mobile value-added services, have realized seamless integration of business applications.

USSD regards the existing GSM mobile communication network as a transparent bearer entity. Mobile operators develop their own USSD services to meet the needs of local users. USSD service can provide data services for mobile users conveniently, but it is very convenient to add new services or modify existing services, thus maintaining the stability of the original system.