GMDSS Maintainer: Element 9

1. A Calibrated in decibels with a sharp internal 1000 Hz bandstop filter.
2. B Calibrated in millivolts with a medium 1000 Hz bandpass filter.
3. C Calibrated in decibels with an internal 1000 Hz highpass filter.
4. D Calibrated in decibels with an internal 1000 Hz lowpass filter.

Tip: press A-D to answer