A USSD menu that displays on a phone, is made up to 160 characters long including white Spaces, which establishes a real-time communication session between the phone and another device — typically, a network or server.

The term USSD stand for Unstructured Supplementary Service Data which works on a Global System for Mobile Communications (GSM) protocol. This mean the USSD service works on every kind and type of mobile phones, so far as it uses the GSM protocol