If the ringer switch is set to no sound, the ringer setting overrides the sound settings and all sounds are turned off.
Your Treo includes a silent alarm that can vibrate even when the ringer switch is set to Sound Mode Off.
System sound settings
You can immediately silence all sounds on your Treo, including phone ringtones, Calendar alerts, and system sounds. This does not mute the speaker on your Treo during a phone call.
Setting the ringer switch
1.Slide the ringer switch to Sound Mode Off.
2.To hear all sounds again, slide the ringer switch to Sound Mode On.
When you slide the ringer switch back to the Sound Mode On position, it restores the previous sound settings. For example, if the phone ring volume is set to 7 and you slide the ringer switch to Sound Mode Off, you will not hear the phone ring. When you move the ringer switch back to Sound Mode On, the phone ring volume is still set to 7.
A | B | A. | Sound Mode On |
|
| B. | Sound Mode Off |
Setting system volume levels
1.Go to Applications 
and select Sounds 
.
2.Select the Application pick list and select General.
3.Select the System Volume and Game Volume pick lists and select a volume level.
4.Select Done.