Unstructured Supplementary Service Data (USSD) is a technology unique to GSM. It is a capability built into the GSM standard for support of transmitting information over the signaling channels of the GSM network. USSD provides session-based communication, enabling a variety of applications.
USSD (Unstructured Supplementary Service Data) is a menu-based system that enables interfacing with content based services. Instead of a browser, which requires an internet / GPRS connection), the USSD menu acts as browser to pull content to the phone. USSD is somewhat faster than SMS because it is a session-based communication, unlike SMS, which is transaction based.
USSD is used as an excellent technology to enable roaming with mobile prepay service .Mobile chatting and friend finder applications are another perfect use for USSD as a menu driven application enabling other applications. USSD is the front-end to these types of applications, which require a menu and fast connections for the user interface.
It is important to note that friend finder applications require location determination/management and presence/availability technologies and applications to allow the closed user group to detect if, when, and where members are available.
How does it work ?