These codes, typically initiated by pressing * or # keys followed by digits and then a send command, are used to interact directly with a mobile network operator. They provide a way to access hidden menus, settings, and services on a device. A common instance involves checking the account balance by dialing a specific sequence that sends a request to the carrier’s system, subsequently displaying the balance on the phone screen.
Understanding these codes enables users to manage their mobile accounts, configure device settings beyond the standard user interface, and troubleshoot basic network connectivity issues. Historically, these codes were vital for earlier mobile technologies; while some functionalities have transitioned to app-based interfaces, certain codes remain essential for specific network-level interactions or device diagnostics.