The phone's audible ringer can be switched off. This only affects the ring and does not affect the visual alerting.
To turn the phone's ringer on/off: (9504/9508)
1.Press the MENU button.
2.Use the up and down arrow keys to locate the option Call Settings....
3.Press the Select soft key.
4.Use the up and down arrow keys to locate the option Audible Alerting.
5.Use the left and right arrow keys or press the On/Off soft key to change the setting.
6.When completed, press the Done soft key.
7.Press the Exit soft key to exit the menus.