To turn on of off the chimes for your Simon XT:
Find the Up Arrow, OK button, and Down arrow to the right of the LCD screen.
Press the Down arrow 3 times until you see CHIME OFF
Press the OK button one time
Press the Down arrow one time until you see CHIME ON
Press the OK button one time
When chimes are enabled, a small black bell icon will be displayed on the Disarmed home screen to the right of the time clock