Turning Treo on and off
You can use the Palm OS® features of your Treo 650 smartphone independently of the wireless features and applications. In other words, the screen and phone are designed to be turned off and on separately.
Turning your phone on and off
When you turn on your Treo, it connects to a mobile network so that you can make and receive phone calls and use other wireless services.
1.Press and hold Power/End 
to turn on your phone. If Sound Mode is on you’ll hear a series of ascending tones. (See “Setting the ringer switch” on page 148 for more on Sound Mode.) After your phone locates a signal, you can use the phone and Internet features (if supported by the local network).
2.Press and hold Power/End 
again to turn off your phone. If Sound Mode is on you‘ll hear a series of descending tones. When your phone is off, your Treo is not connected to any mobile network. You can still use the organizer and other Palm OS features. This is ideal for airplane flights and for maximizing battery life.
Waking up the screen
To use the Palm OS features when your phone is off, you need to wake up the screen. You can also turn off your phone’s screen without turning off your phone’s wireless features.
1.Press Power/End 
to wake up the screen.
2.Briefly press Power/End 
to turn off the screen.
The indicator light flashes green when your phone is on and you’re inside a coverage area. If you’re outside a coverage area, the indicator light flashes amber.
Your Treo 650 includes a keyboard backlight for low- light conditions. The keyboard backlight activates automatically when the screen turns on. It turns off automatically when the screen turns off and when an active call lasts longer than a minute.
You can also press any application buttons on the front of your phone to wake up the screen and go directly to the application linked to that button.