Furuno GP-3500 - Manual (Page 109)

8. ALARMS
8-5
8.4 Proximity Alarm
The proximity alarm alerts you when your vessel nears a waypoint by the
distance set for that waypoint on the waypoints list. The distance is called the
proximity alarm radius. You can globally activate or deactivate the proximity
alarm here.
Alarm range (Radius depends on
the setting of "PRXMTY RADIUS"
in the waypoint editing window.)
000001
Proximity alarm
1. Press the [MENU] key to show the main menu.
2. Press the [6] key to show the ALARMS SETUP menu.
3. Rotate the [ENTER] knob to select PROXIMITY ALARM.
4. Press the [1] key to select “1. ON.”
5. Press the [MENU] key several times to close the menu.
Note: To deactivate the alarm, select “2. OFF” at step 4.