Backlight Timeout—sets the backlight to stay on when it is turnedon, or to time out after a selected period of time has elapsed whenusing the battery. The backlight stays on regardless of this settingwhen external power is used.Twilight Adjustment—allows the unit to adjust the backlight foroptimum viewing during twilight times.Highway Page—indicates whether the Highway Page appears in themain page sequence.XM Audio Page—indicates whether the XM Audio Page appears inthe main page sequence.Compass Page—indicates whether the Compass Page appears in themain page sequence.Backlight Intensity—turns the backlight up or down. Press right onthe ROCKER to increase the intensity or left to decrease.Sound TabUse the Sound tab to customize the sounds made by the unit.To access the Sound tab:1. Press MENU twice to open the Main Menu.2. Use the ROCKER to highlight the Sound tab.Main Menu—Sound TabBeeper—sets the beeper to chime during keypresses and alarms(Key and Alarm) or on Alarms Only.Audio Jack—sets the Audio Jack output for Headphones orLine Out.Attention Tone—turns on and off the attention tone that soundsbefore the vocal prompts.Voice Prompt—sets the vocal prompt to operate for Guidance andStatus, Route Guidance Only, or No Voice Prompts.Voice Language—sets the language for vocal prompts.Speaker Volume—sets the external speaker or headphone volume.86 GPSMAP 378/478 Owner’s ManualM AIN MENU > SOUND TAB
