USSD stands for Unstructured Supplementary Service Data is a Global System for all GSM phones and used to sends text between a mobile phone and an applicationprogram in the network. It is generally associated with real-time or instant messaging type phone services. There is no store and forward capability for USSD therefore response times for interactive USSD-based services are generally quickerthan those used for SMS.

 Characteristics of USSD:

 •A USSD message can be up to 182 alphanumeric characters in length 

•Unlike SMS, USSD is a session oriented service 

•Simple and easy to send.  

•There will not be any latency in request and response as we experience in SMS based services.