Unstructured Supplementary Services Data (USSD) is a session based service unlike SMS which is a store and forward service. USSD services are provided with two different service features:
Under this feature departments are allowed to send messages to the subscribers/end users. These are simple FLASH to the handset. Subscribers cannot respond to these messages. These are non-menu based and are used just for a notification or an info flash. USSD will send an acknowledgement to the application once the flash is submitted to the handset. These acknowledgements are flash based.
Under this feature, departments have the facility to send menu to the subscribers in place of a simple flash. The department has to imitate the messages as a Push to the handset with defined menu and actions. After receiving the menu, subscribers/end-users can send the response over as a second session. Thus under USSR, a department has to have a menu and functional options for each session. These are more interactive and application related. The USSR service will be available on *166#.
Following is the USSD demo using temporary short code.