Lock your device
If you are not on a call, you can lock the keyboard to avoid pressing keys accidentally when you are playing a song or when you are not using your BlackBerry® device. If your email account uses a BlackBerry® Enterprise Server, depending on the options that your administrator sets, you might not be able to perform this task. For more information, contact your administrator.
After you finish:
To unlock your device, type your device password. Press the Enter key. To unlock the keyboard, press and hold the 
key again.
key again. Previous topic: Change the device password