GPSMAP 496 Owner’s Manual 0MAIn Menu > celestIAl tAbSystem Alarms Sub TabSystem Alarms Sub TabClock—sets an alarm based on the unit’s clock. Select on, and thenenter a specific time that you want the alarm to sound. The unit mustbe on for the clock alarm to work.Ext. (External) Voltage—sets an alarm to sound when the externalvoltage drops below a specified amount. Select on, and then enter aspecific voltage.DgpS—sets an alarm to sound when the unit loses a differential fix.accuracy—sets an alarm to sound when GPS accuracy falls outsideof the user-set value. Select on, and then enter a specific distance.Sonar Alarms Sub Tab (Marine Mode Only)You must be receiving sonar NMEA data for Sonar alarms to work.Sonar Alarms Sub TabShallow Water and Deep Water—sets an alarm to sound when youenter an area of water that is too shallow or deep.Water temp—sets an alarm to indicate if the water temperature hasexceeded or dropped below a specific temperature, or fallen outside/inside a specific temperature range. Select above or Below and thenenter a specific temperature, or select inside or outside and enter arange of temperatures.Drift—sets an alarm to sound when you have exceeded a specifieddrift distance. Select on, and then enter a specific distance.Fish—sets alarm to sound when unit detects a fish of the specifiedsymbol size.
