NorthStar 961 Reference Manual page 260

Chapter 12 - Alarms, TideTrack, Currents, and Echo Sounding
Understanding the
alarm audio
Page 12-10
2. Press the CURSOR PAD up or down to highlight the
desired alarm setting.
To turn off an alarm setting, press the ALARM ON/OFF
key. When done, press the ACCEPT key (or press
CANCEL to leave the alarm on).
To change the distance setting for the cross-track, arrival
radius, or anchor drag alarms, highlight the desired alarm
setting, then use the KEYPAD to enter the distance at
which you want to be alerted. If necessary, press the LEFT
ARROW and RIGHT ARROW to move the cursor into the
desired decimal place. When done, press the ACCEPT key
(or press CANCEL to leave the value unchanged).
The alarm audio for most of the alarms can be turned off,
which means the alarms won't beep for any of those alarm
situations. However, even with the alarm audio off, you'll still
see the alarm messages displayed onscreen.
You can set the alarms to emit seven different levels of sound
from low to high, or else turn the alarm audio off. The
961/962 Operations and Reference Manual, Rev. A
Alarm settings screen