9.6.2 Visual Alarms

• Visual alarms should clearly differ from routine information on displays.

• Visual alarms should be flashing. The flashing display should change to steady display upon acknowledgement.

• Acknowledged alarms should be presented by steady display.

• Alarm indicators should be designed to show no light in normal conditions (no alarm) or should be nonexistent on displays.

• Flashing visual alarms should be illuminated for at least 50% of the cycle and have a pulse frequency in the range of 0.5 Hz to 1.5 Hz.

• Visual alarms on the navigating bridge should not interfere with night vision (not applicable in the ECR).

9.6.3 Audible Alarms

• Audible alarms should be used simultaneously with visual alarms.

• Audible alarms should cease upon acknowledgement.

• Audible alarms should be differentiated from routine signals, such as bells, buzzers, and normal operation noises.

• Under normal working conditions, the alarm signals should be able to be heard properly inside the wheelhouse and outside on the bridge wings, and their sound characteristics should not be inconvenient to the human ear (not applicable in the ECR). This point is underspecified, and difficult to judge whether it has been fulfilled.