In Huawei lithium battery cabinet alarm design, the MDU indicator and buzzer are coordinated to help O&M personnel immediately judge alarm severity without logging into a management system. Acritical alarmindicates that the battery system may no longer be in a fully safe or supported operating state and requires urgent handling, such as load protection actions, isolation, or immediate inspection. For this highest severity level, the cabinet uses the most prominent visual pattern:red with fast blinking, paired with acontinuous buzzer, to ensure the condition cannot be overlooked in an equipment room environment. Yellow indicators are reserved for lower severities such as warnings or minor/major alarms, where the system remains controllable and the required response can be scheduled. A steady red is typically used to indicate a persistent fault state or stop condition, whereasfast blinking red + continuous buzzeris the clear “critical, urgent” combination that triggers immediate on-site response and rapid fault localization (such as checking protection events, contactor status, temperature/voltage exceptions, and isolation conditions).