View of the throttle and panel A and C. The top right part of panel C has buzzer called BZ V-O-F. It can emit three tones and is used to indicate four situations - V: Vigilance warning, O: Over-speeding and F: excess airflow in brake pipe. An audible warning is also generated when a fire is detected in the machine room. The tone is at a frequency of 1170 Hz. The red indication lamp in the center is LSFI - to indicate a priority 1 fault and the yellow illuminated button below is BPFA : to indicate and acknowledge a fault.