VDR is a simple equipment. It records the data from the equipments that are connected to it.

If it fails to record the data from any of the equipments, it will give an error with an error code. The error code can be checked from the list of errors to know the reason for the error.

For example if we switch off the echo sounder, the VDR would give an error with an alarm.

Even if there is an internal VDR error, there would still be an error with alarm.

If there is no alarm on the VDR panel, it would mean that VDR is working properly.