Issues a control command to the device's Bit Error Rate Test (BERT) engine, selecting actions such as starting, stopping, clearing results, inserting a test error, or arming a timer. The DESCRIPTION in this MIB is empty, so this reading is inferred from the object name and its enumerated command values rather than vendor text. An admin verifying a suspect circuit's error performance would set this to start(1) to begin a BERT run and later stop(2) to end it.