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USSD Unstructured Supplementary Service Data

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USSD: Unstructured Supplementary Service Data

Unstructured Supplementary Service Data (USSD) is a communication protocol used by mobile phones to send and receive text-based information between a mobile device and the service provider's computer systems. USSD is widely used for various interactive services, such as mobile banking, balance inquiries, mobile top-ups, and menu-based services.

How USSD Works:

  1. Dialing a USSD Code: To initiate a USSD session, a mobile phone user dials a specific USSD code on their device. The USSD code typically starts with a "*" (star) and ends with a "#" (hash) character. For example, *123# could be a USSD code to check account balance.
  2. Establishing the USSD Session: When the user enters the USSD code and presses the call or send button, the mobile device establishes a session with the service provider's computer systems over the mobile network.
  3. Request and Response: The mobile device sends the USSD code as a request to the service provider's USSD gateway. The USSD gateway interprets the code and processes the request. The service provider's computer systems generate a response to the request.
  4. Response Display: The response from the service provider's computer systems is sent back to the mobile device, and the user can view the response on their screen. The response usually contains text-based information or a menu with options for the user to choose from.
  5. Session Termination: After the user receives the response or takes appropriate action based on the menu options, the USSD session is terminated. The user can choose to exit the USSD session by ending the call, entering another USSD code, or the session may have a predefined timeout period.

Key Characteristics of USSD:

  1. Real-time Interaction: USSD sessions provide real-time interaction between the mobile user and the service provider's computer systems. This makes USSD useful for applications that require immediate responses, such as balance inquiries or transaction notifications.
  2. Session-Based: USSD sessions are session-based, meaning each USSD request-response exchange is treated as a single session. Once the session is terminated, the user needs to initiate a new USSD session for further interactions.
  3. Text-Based Communication: USSD uses text-based communication, which makes it compatible with even basic mobile phones that do not support data services or internet connectivity.
  4. No Storing of Data on the Mobile Device: USSD does not store any data on the mobile device, making it a secure method for certain transactions and services.
  5. Fast and Lightweight: USSD is a lightweight protocol, and its exchanges are usually faster than SMS (Short Message Service) and other communication methods, making it suitable for time-sensitive services.

Applications of USSD:

USSD is used in various applications, including:

  1. Mobile Banking: Users can check their account balances, transfer funds, pay bills, and perform other banking transactions using USSD codes.
  2. Mobile Top-ups: Users can recharge their prepaid mobile phone accounts using USSD codes.
  3. Service Activation and Deactivation: Users can activate or deactivate services like call forwarding, call waiting, and data packages using USSD.
  4. Menu-Based Services: USSD menus allow users to navigate through different options and select specific services, such as checking data usage, activating roaming, and managing subscriptions.
  5. Interactive Voting and Surveys: USSD is used for interactive voting, surveys, and polls, where users can provide their responses using USSD codes.

Conclusion:

Unstructured Supplementary Service Data (USSD) is a text-based communication protocol that allows mobile phones to interact with service provider computer systems in real-time. It is widely used for various interactive services, offering a fast, lightweight, and secure method for users to access information and perform transactions on their mobile devices. USSD plays a significant role in mobile banking, mobile top-ups, menu-based services, and other interactive applications.